From 9c61e789546810ee63708568737cb990d2b86605 Mon Sep 17 00:00:00 2001 From: Christian König Date: Wed, 5 May 2021 11:40:54 +0200 Subject: dma-buf: some dma_fence_chain improvements MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The callback and the irq work are never used at the same time. Putting them into an union saves us 24 bytes and makes the structure only 120 bytes in size. Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210611120301.10595-2-christian.koenig@amd.com --- include/linux/dma-fence-chain.h | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h index 10462a029da2..c6eb3aa45668 100644 --- a/include/linux/dma-fence-chain.h +++ b/include/linux/dma-fence-chain.h @@ -16,21 +16,36 @@ /** * struct dma_fence_chain - fence to represent an node of a fence chain * @base: fence base class - * @lock: spinlock for fence handling * @prev: previous fence of the chain * @prev_seqno: original previous seqno before garbage collection * @fence: encapsulated fence - * @cb: callback structure for signaling - * @work: irq work item for signaling + * @lock: spinlock for fence handling */ struct dma_fence_chain { struct dma_fence base; - spinlock_t lock; struct dma_fence __rcu *prev; u64 prev_seqno; struct dma_fence *fence; - struct dma_fence_cb cb; - struct irq_work work; + union { + /** + * @cb: callback for signaling + * + * This is used to add the callback for signaling the + * complection of the fence chain. Never used at the same time + * as the irq work. + */ + struct dma_fence_cb cb; + + /** + * @work: irq work item for signaling + * + * Irq work structure to allow us to add the callback without + * running into lock inversion. Never used at the same time as + * the callback. + */ + struct irq_work work; + }; + spinlock_t lock; }; extern const struct dma_fence_ops dma_fence_chain_ops; -- cgit v1.2.3 From 440d0f12b52a920f4c78376b3ce7039ba59244c5 Mon Sep 17 00:00:00 2001 From: Christian König Date: Wed, 5 May 2021 13:38:12 +0200 Subject: dma-buf: add dma_fence_chain_alloc/free v3 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a common allocation helper. Cleaning up the mix of kzalloc/kmalloc and some unused code in the selftest. v2: polish kernel doc a bit v3: polish kernel doc even a bit more Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210611120301.10595-3-christian.koenig@amd.com --- drivers/dma-buf/st-dma-fence-chain.c | 16 ++++------------ drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 4 ++-- drivers/gpu/drm/drm_syncobj.c | 6 +++--- drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 6 ++---- drivers/gpu/drm/msm/msm_gem_submit.c | 6 ++---- include/linux/dma-fence-chain.h | 25 +++++++++++++++++++++++++ 6 files changed, 38 insertions(+), 25 deletions(-) (limited to 'include/linux') diff --git a/drivers/dma-buf/st-dma-fence-chain.c b/drivers/dma-buf/st-dma-fence-chain.c index 9525f7f56119..8ce1ea59d31b 100644 --- a/drivers/dma-buf/st-dma-fence-chain.c +++ b/drivers/dma-buf/st-dma-fence-chain.c @@ -58,28 +58,20 @@ static struct dma_fence *mock_fence(void) return &f->base; } -static inline struct mock_chain { - struct dma_fence_chain base; -} *to_mock_chain(struct dma_fence *f) { - return container_of(f, struct mock_chain, base.base); -} - static struct dma_fence *mock_chain(struct dma_fence *prev, struct dma_fence *fence, u64 seqno) { - struct mock_chain *f; + struct dma_fence_chain *f; - f = kmalloc(sizeof(*f), GFP_KERNEL); + f = dma_fence_chain_alloc(); if (!f) return NULL; - dma_fence_chain_init(&f->base, - dma_fence_get(prev), - dma_fence_get(fence), + dma_fence_chain_init(f, dma_fence_get(prev), dma_fence_get(fence), seqno); - return &f->base.base; + return &f->base; } static int sanitycheck(void *arg) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c index 1476236f5c7c..9ce649a1a8d3 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c @@ -1109,7 +1109,7 @@ static int amdgpu_cs_process_syncobj_timeline_out_dep(struct amdgpu_cs_parser *p dep->chain = NULL; if (syncobj_deps[i].point) { - dep->chain = kmalloc(sizeof(*dep->chain), GFP_KERNEL); + dep->chain = dma_fence_chain_alloc(); if (!dep->chain) return -ENOMEM; } @@ -1117,7 +1117,7 @@ static int amdgpu_cs_process_syncobj_timeline_out_dep(struct amdgpu_cs_parser *p dep->syncobj = drm_syncobj_find(p->filp, syncobj_deps[i].handle); if (!dep->syncobj) { - kfree(dep->chain); + dma_fence_chain_free(dep->chain); return -EINVAL; } dep->point = syncobj_deps[i].point; diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index fdd2ec87cdd1..1c5b9ef6da37 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -861,7 +861,7 @@ static int drm_syncobj_transfer_to_timeline(struct drm_file *file_private, &fence); if (ret) goto err; - chain = kzalloc(sizeof(struct dma_fence_chain), GFP_KERNEL); + chain = dma_fence_chain_alloc(); if (!chain) { ret = -ENOMEM; goto err1; @@ -1402,10 +1402,10 @@ drm_syncobj_timeline_signal_ioctl(struct drm_device *dev, void *data, goto err_points; } for (i = 0; i < args->count_handles; i++) { - chains[i] = kzalloc(sizeof(struct dma_fence_chain), GFP_KERNEL); + chains[i] = dma_fence_chain_alloc(); if (!chains[i]) { for (j = 0; j < i; j++) - kfree(chains[j]); + dma_fence_chain_free(chains[j]); ret = -ENOMEM; goto err_chains; } diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index a8abc9af5ff4..8e195fa7626a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -2983,7 +2983,7 @@ __free_fence_array(struct eb_fence *fences, unsigned int n) while (n--) { drm_syncobj_put(ptr_mask_bits(fences[n].syncobj, 2)); dma_fence_put(fences[n].dma_fence); - kfree(fences[n].chain_fence); + dma_fence_chain_free(fences[n].chain_fence); } kvfree(fences); } @@ -3097,9 +3097,7 @@ add_timeline_fence_array(struct i915_execbuffer *eb, return -EINVAL; } - f->chain_fence = - kmalloc(sizeof(*f->chain_fence), - GFP_KERNEL); + f->chain_fence = dma_fence_chain_alloc(); if (!f->chain_fence) { drm_syncobj_put(syncobj); dma_fence_put(fence); diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c index 5480852bdeda..6ff6df6c4791 100644 --- a/drivers/gpu/drm/msm/msm_gem_submit.c +++ b/drivers/gpu/drm/msm/msm_gem_submit.c @@ -586,9 +586,7 @@ static struct msm_submit_post_dep *msm_parse_post_deps(struct drm_device *dev, break; } - post_deps[i].chain = - kmalloc(sizeof(*post_deps[i].chain), - GFP_KERNEL); + post_deps[i].chain = dma_fence_chain_alloc(); if (!post_deps[i].chain) { ret = -ENOMEM; break; @@ -605,7 +603,7 @@ static struct msm_submit_post_dep *msm_parse_post_deps(struct drm_device *dev, if (ret) { for (j = 0; j <= i; ++j) { - kfree(post_deps[j].chain); + dma_fence_chain_free(post_deps[j].chain); if (post_deps[j].syncobj) drm_syncobj_put(post_deps[j].syncobj); } diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h index c6eb3aa45668..54fe3443fd2c 100644 --- a/include/linux/dma-fence-chain.h +++ b/include/linux/dma-fence-chain.h @@ -12,6 +12,7 @@ #include #include +#include /** * struct dma_fence_chain - fence to represent an node of a fence chain @@ -66,6 +67,30 @@ to_dma_fence_chain(struct dma_fence *fence) return container_of(fence, struct dma_fence_chain, base); } +/** + * dma_fence_chain_alloc + * + * Returns a new struct dma_fence_chain object or NULL on failure. + */ +static inline struct dma_fence_chain *dma_fence_chain_alloc(void) +{ + return kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL); +}; + +/** + * dma_fence_chain_free + * @chain: chain node to free + * + * Frees up an allocated but not used struct dma_fence_chain object. This + * doesn't need an RCU grace period since the fence was never initialized nor + * published. After dma_fence_chain_init() has been called the fence must be + * released by calling dma_fence_put(), and not through this function. + */ +static inline void dma_fence_chain_free(struct dma_fence_chain *chain) +{ + kfree(chain); +}; + /** * dma_fence_chain_for_each - iterate over all fences in chain * @iter: current fence -- cgit v1.2.3 From bdb8d06dfefd666d5981d884b535b04105869fcc Mon Sep 17 00:00:00 2001 From: Hridya Valsaraju Date: Thu, 3 Jun 2021 14:47:51 -0700 Subject: dmabuf: Add the capability to expose DMA-BUF stats in sysfs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Overview ======== The patch adds DMA-BUF statistics to /sys/kernel/dmabuf/buffers. It allows statistics to be enabled for each DMA-BUF in sysfs by enabling the config CONFIG_DMABUF_SYSFS_STATS. The following stats will be exposed by the interface: /sys/kernel/dmabuf/buffers//exporter_name /sys/kernel/dmabuf/buffers//size /sys/kernel/dmabuf/buffers//attachments//device /sys/kernel/dmabuf/buffers//attachments//map_counter The inode_number is unique for each DMA-BUF and was added earlier [1] in order to allow userspace to track DMA-BUF usage across different processes. Use Cases ========= The interface provides a way to gather DMA-BUF per-buffer statistics from production devices. These statistics will be used to derive DMA-BUF per-exporter stats and per-device usage stats for Android Bug reports. The corresponding userspace changes can be found at [2]. Telemetry tools will also capture this information(along with other memory metrics) periodically as well as on important events like a foreground app kill (which might have been triggered by Low Memory Killer). It will also contribute to provide a snapshot of the system memory usage on other events such as OOM kills and Application Not Responding events. Background ========== Currently, there are two existing interfaces that provide information about DMA-BUFs. 1) /sys/kernel/debug/dma_buf/bufinfo debugfs is however unsuitable to be mounted in production systems and cannot be considered as an alternative to the sysfs interface being proposed. 2) proc//fdinfo/ The proc//fdinfo/ files expose information about DMA-BUF fds. However, the existing procfs interfaces can only provide information about the buffers for which processes hold fds or have the buffers mmapped into their address space. Since the procfs interfaces alone cannot provide a full picture of all DMA-BUFs in the system, there is the need for an alternate interface to provide this information on production systems. The patch contains the following major improvements over v1: 1) Each attachment is represented by its own directory to allow creating a symlink to the importing device and to also provide room for future expansion. 2) The number of distinct mappings of each attachment is exposed in a separate file. 3) The per-buffer statistics are now in /sys/kernel/dmabuf/buffers inorder to make the interface expandable in future. All of the improvements above are based on suggestions/feedback from Daniel Vetter and Christian König. A shell script that can be run on a classic Linux environment to read out the DMA-BUF statistics can be found at [3](suggested by John Stultz). [1]: https://lore.kernel.org/patchwork/patch/1088791/ [2]: https://android-review.googlesource.com/q/topic:%22dmabuf-sysfs%22+(status:open%20OR%20status:merged) [3]: https://android-review.googlesource.com/c/platform/system/memory/libmeminfo/+/1549734 Reviewed-by: Greg Kroah-Hartman Signed-off-by: Hridya Valsaraju Reported-by: kernel test robot Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210603214758.2955251-1-hridya@google.com --- .../ABI/testing/sysfs-kernel-dmabuf-buffers | 52 ++++ Documentation/driver-api/dma-buf.rst | 5 + drivers/dma-buf/Kconfig | 11 + drivers/dma-buf/Makefile | 1 + drivers/dma-buf/dma-buf-sysfs-stats.c | 337 +++++++++++++++++++++ drivers/dma-buf/dma-buf-sysfs-stats.h | 62 ++++ drivers/dma-buf/dma-buf.c | 37 +++ include/linux/dma-buf.h | 20 ++ 8 files changed, 525 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers create mode 100644 drivers/dma-buf/dma-buf-sysfs-stats.c create mode 100644 drivers/dma-buf/dma-buf-sysfs-stats.h (limited to 'include/linux') diff --git a/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers b/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers new file mode 100644 index 000000000000..a243984ed420 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers @@ -0,0 +1,52 @@ +What: /sys/kernel/dmabuf/buffers +Date: May 2021 +KernelVersion: v5.13 +Contact: Hridya Valsaraju +Description: The /sys/kernel/dmabuf/buffers directory contains a + snapshot of the internal state of every DMA-BUF. + /sys/kernel/dmabuf/buffers/ will contain the + statistics for the DMA-BUF with the unique inode number + +Users: kernel memory tuning/debugging tools + +What: /sys/kernel/dmabuf/buffers//exporter_name +Date: May 2021 +KernelVersion: v5.13 +Contact: Hridya Valsaraju +Description: This file is read-only and contains the name of the exporter of + the DMA-BUF. + +What: /sys/kernel/dmabuf/buffers//size +Date: May 2021 +KernelVersion: v5.13 +Contact: Hridya Valsaraju +Description: This file is read-only and specifies the size of the DMA-BUF in + bytes. + +What: /sys/kernel/dmabuf/buffers//attachments +Date: May 2021 +KernelVersion: v5.13 +Contact: Hridya Valsaraju +Description: This directory will contain subdirectories representing every + attachment of the DMA-BUF. + +What: /sys/kernel/dmabuf/buffers//attachments/ +Date: May 2021 +KernelVersion: v5.13 +Contact: Hridya Valsaraju +Description: This directory will contain information on the attached device + and the number of current distinct device mappings. + +What: /sys/kernel/dmabuf/buffers//attachments//device +Date: May 2021 +KernelVersion: v5.13 +Contact: Hridya Valsaraju +Description: This file is read-only and is a symlink to the attached device's + sysfs entry. + +What: /sys/kernel/dmabuf/buffers//attachments//map_counter +Date: May 2021 +KernelVersion: v5.13 +Contact: Hridya Valsaraju +Description: This file is read-only and contains a map_counter indicating the + number of distinct device mappings of the attachment. diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst index 7f21425d9435..84aab65c4962 100644 --- a/Documentation/driver-api/dma-buf.rst +++ b/Documentation/driver-api/dma-buf.rst @@ -106,6 +106,11 @@ Implicit Fence Poll Support .. kernel-doc:: drivers/dma-buf/dma-buf.c :doc: implicit fence polling +DMA-BUF statistics +~~~~~~~~~~~~~~~~~~ +.. kernel-doc:: drivers/dma-buf/dma-buf-sysfs-stats.c + :doc: overview + Kernel Functions and Structures Reference ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index 4e16c71c24b7..9561e3d2d428 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -72,6 +72,17 @@ menuconfig DMABUF_HEAPS allows userspace to allocate dma-bufs that can be shared between drivers. +menuconfig DMABUF_SYSFS_STATS + bool "DMA-BUF sysfs statistics" + select DMA_SHARED_BUFFER + help + Choose this option to enable DMA-BUF sysfs statistics + in location /sys/kernel/dmabuf/buffers. + + /sys/kernel/dmabuf/buffers/ will contain + statistics for the DMA-BUF with the unique inode number + . + source "drivers/dma-buf/heaps/Kconfig" endmenu diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index 995e05f609ff..40d81f23cacf 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_DMABUF_HEAPS) += heaps/ obj-$(CONFIG_SYNC_FILE) += sync_file.o obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o obj-$(CONFIG_UDMABUF) += udmabuf.o +obj-$(CONFIG_DMABUF_SYSFS_STATS) += dma-buf-sysfs-stats.o dmabuf_selftests-y := \ selftest.o \ diff --git a/drivers/dma-buf/dma-buf-sysfs-stats.c b/drivers/dma-buf/dma-buf-sysfs-stats.c new file mode 100644 index 000000000000..a2638e84199c --- /dev/null +++ b/drivers/dma-buf/dma-buf-sysfs-stats.c @@ -0,0 +1,337 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * DMA-BUF sysfs statistics. + * + * Copyright (C) 2021 Google LLC. + */ + +#include +#include +#include +#include +#include +#include + +#include "dma-buf-sysfs-stats.h" + +#define to_dma_buf_entry_from_kobj(x) container_of(x, struct dma_buf_sysfs_entry, kobj) + +/** + * DOC: overview + * + * ``/sys/kernel/debug/dma_buf/bufinfo`` provides an overview of every DMA-BUF + * in the system. However, since debugfs is not safe to be mounted in + * production, procfs and sysfs can be used to gather DMA-BUF statistics on + * production systems. + * + * The ``/proc//fdinfo/`` files in procfs can be used to gather + * information about DMA-BUF fds. Detailed documentation about the interface + * is present in Documentation/filesystems/proc.rst. + * + * Unfortunately, the existing procfs interfaces can only provide information + * about the DMA-BUFs for which processes hold fds or have the buffers mmapped + * into their address space. This necessitated the creation of the DMA-BUF sysfs + * statistics interface to provide per-buffer information on production systems. + * + * The interface at ``/sys/kernel/dma-buf/buffers`` exposes information about + * every DMA-BUF when ``CONFIG_DMABUF_SYSFS_STATS`` is enabled. + * + * The following stats are exposed by the interface: + * + * * ``/sys/kernel/dmabuf/buffers//exporter_name`` + * * ``/sys/kernel/dmabuf/buffers//size`` + * * ``/sys/kernel/dmabuf/buffers//attachments//device`` + * * ``/sys/kernel/dmabuf/buffers//attachments//map_counter`` + * + * The information in the interface can also be used to derive per-exporter and + * per-device usage statistics. The data from the interface can be gathered + * on error conditions or other important events to provide a snapshot of + * DMA-BUF usage. It can also be collected periodically by telemetry to monitor + * various metrics. + * + * Detailed documentation about the interface is present in + * Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers. + */ + +struct dma_buf_stats_attribute { + struct attribute attr; + ssize_t (*show)(struct dma_buf *dmabuf, + struct dma_buf_stats_attribute *attr, char *buf); +}; +#define to_dma_buf_stats_attr(x) container_of(x, struct dma_buf_stats_attribute, attr) + +static ssize_t dma_buf_stats_attribute_show(struct kobject *kobj, + struct attribute *attr, + char *buf) +{ + struct dma_buf_stats_attribute *attribute; + struct dma_buf_sysfs_entry *sysfs_entry; + struct dma_buf *dmabuf; + + attribute = to_dma_buf_stats_attr(attr); + sysfs_entry = to_dma_buf_entry_from_kobj(kobj); + dmabuf = sysfs_entry->dmabuf; + + if (!dmabuf || !attribute->show) + return -EIO; + + return attribute->show(dmabuf, attribute, buf); +} + +static const struct sysfs_ops dma_buf_stats_sysfs_ops = { + .show = dma_buf_stats_attribute_show, +}; + +static ssize_t exporter_name_show(struct dma_buf *dmabuf, + struct dma_buf_stats_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%s\n", dmabuf->exp_name); +} + +static ssize_t size_show(struct dma_buf *dmabuf, + struct dma_buf_stats_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%zu\n", dmabuf->size); +} + +static struct dma_buf_stats_attribute exporter_name_attribute = + __ATTR_RO(exporter_name); +static struct dma_buf_stats_attribute size_attribute = __ATTR_RO(size); + +static struct attribute *dma_buf_stats_default_attrs[] = { + &exporter_name_attribute.attr, + &size_attribute.attr, + NULL, +}; +ATTRIBUTE_GROUPS(dma_buf_stats_default); + +static void dma_buf_sysfs_release(struct kobject *kobj) +{ + struct dma_buf_sysfs_entry *sysfs_entry; + + sysfs_entry = to_dma_buf_entry_from_kobj(kobj); + kfree(sysfs_entry); +} + +static struct kobj_type dma_buf_ktype = { + .sysfs_ops = &dma_buf_stats_sysfs_ops, + .release = dma_buf_sysfs_release, + .default_groups = dma_buf_stats_default_groups, +}; + +#define to_dma_buf_attach_entry_from_kobj(x) container_of(x, struct dma_buf_attach_sysfs_entry, kobj) + +struct dma_buf_attach_stats_attribute { + struct attribute attr; + ssize_t (*show)(struct dma_buf_attach_sysfs_entry *sysfs_entry, + struct dma_buf_attach_stats_attribute *attr, char *buf); +}; +#define to_dma_buf_attach_stats_attr(x) container_of(x, struct dma_buf_attach_stats_attribute, attr) + +static ssize_t dma_buf_attach_stats_attribute_show(struct kobject *kobj, + struct attribute *attr, + char *buf) +{ + struct dma_buf_attach_stats_attribute *attribute; + struct dma_buf_attach_sysfs_entry *sysfs_entry; + + attribute = to_dma_buf_attach_stats_attr(attr); + sysfs_entry = to_dma_buf_attach_entry_from_kobj(kobj); + + if (!attribute->show) + return -EIO; + + return attribute->show(sysfs_entry, attribute, buf); +} + +static const struct sysfs_ops dma_buf_attach_stats_sysfs_ops = { + .show = dma_buf_attach_stats_attribute_show, +}; + +static ssize_t map_counter_show(struct dma_buf_attach_sysfs_entry *sysfs_entry, + struct dma_buf_attach_stats_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%u\n", sysfs_entry->map_counter); +} + +static struct dma_buf_attach_stats_attribute map_counter_attribute = + __ATTR_RO(map_counter); + +static struct attribute *dma_buf_attach_stats_default_attrs[] = { + &map_counter_attribute.attr, + NULL, +}; +ATTRIBUTE_GROUPS(dma_buf_attach_stats_default); + +static void dma_buf_attach_sysfs_release(struct kobject *kobj) +{ + struct dma_buf_attach_sysfs_entry *sysfs_entry; + + sysfs_entry = to_dma_buf_attach_entry_from_kobj(kobj); + kfree(sysfs_entry); +} + +static struct kobj_type dma_buf_attach_ktype = { + .sysfs_ops = &dma_buf_attach_stats_sysfs_ops, + .release = dma_buf_attach_sysfs_release, + .default_groups = dma_buf_attach_stats_default_groups, +}; + +void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach) +{ + struct dma_buf_attach_sysfs_entry *sysfs_entry; + + sysfs_entry = attach->sysfs_entry; + if (!sysfs_entry) + return; + + sysfs_delete_link(&sysfs_entry->kobj, &attach->dev->kobj, "device"); + + kobject_del(&sysfs_entry->kobj); + kobject_put(&sysfs_entry->kobj); +} + +int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach, + unsigned int uid) +{ + struct dma_buf_attach_sysfs_entry *sysfs_entry; + int ret; + struct dma_buf *dmabuf; + + if (!attach) + return -EINVAL; + + dmabuf = attach->dmabuf; + + sysfs_entry = kzalloc(sizeof(struct dma_buf_attach_sysfs_entry), + GFP_KERNEL); + if (!sysfs_entry) + return -ENOMEM; + + sysfs_entry->kobj.kset = dmabuf->sysfs_entry->attach_stats_kset; + + attach->sysfs_entry = sysfs_entry; + + ret = kobject_init_and_add(&sysfs_entry->kobj, &dma_buf_attach_ktype, + NULL, "%u", uid); + if (ret) + goto kobj_err; + + ret = sysfs_create_link(&sysfs_entry->kobj, &attach->dev->kobj, + "device"); + if (ret) + goto link_err; + + return 0; + +link_err: + kobject_del(&sysfs_entry->kobj); +kobj_err: + kobject_put(&sysfs_entry->kobj); + attach->sysfs_entry = NULL; + + return ret; +} +void dma_buf_stats_teardown(struct dma_buf *dmabuf) +{ + struct dma_buf_sysfs_entry *sysfs_entry; + + sysfs_entry = dmabuf->sysfs_entry; + if (!sysfs_entry) + return; + + kset_unregister(sysfs_entry->attach_stats_kset); + kobject_del(&sysfs_entry->kobj); + kobject_put(&sysfs_entry->kobj); +} + + +/* Statistics files do not need to send uevents. */ +static int dmabuf_sysfs_uevent_filter(struct kset *kset, struct kobject *kobj) +{ + return 0; +} + +static const struct kset_uevent_ops dmabuf_sysfs_no_uevent_ops = { + .filter = dmabuf_sysfs_uevent_filter, +}; + +static struct kset *dma_buf_stats_kset; +static struct kset *dma_buf_per_buffer_stats_kset; +int dma_buf_init_sysfs_statistics(void) +{ + dma_buf_stats_kset = kset_create_and_add("dmabuf", + &dmabuf_sysfs_no_uevent_ops, + kernel_kobj); + if (!dma_buf_stats_kset) + return -ENOMEM; + + dma_buf_per_buffer_stats_kset = kset_create_and_add("buffers", + &dmabuf_sysfs_no_uevent_ops, + &dma_buf_stats_kset->kobj); + if (!dma_buf_per_buffer_stats_kset) { + kset_unregister(dma_buf_stats_kset); + return -ENOMEM; + } + + return 0; +} + +void dma_buf_uninit_sysfs_statistics(void) +{ + kset_unregister(dma_buf_per_buffer_stats_kset); + kset_unregister(dma_buf_stats_kset); +} + +int dma_buf_stats_setup(struct dma_buf *dmabuf) +{ + struct dma_buf_sysfs_entry *sysfs_entry; + int ret; + struct kset *attach_stats_kset; + + if (!dmabuf || !dmabuf->file) + return -EINVAL; + + if (!dmabuf->exp_name) { + pr_err("exporter name must not be empty if stats needed\n"); + return -EINVAL; + } + + sysfs_entry = kzalloc(sizeof(struct dma_buf_sysfs_entry), GFP_KERNEL); + if (!sysfs_entry) + return -ENOMEM; + + sysfs_entry->kobj.kset = dma_buf_per_buffer_stats_kset; + sysfs_entry->dmabuf = dmabuf; + + dmabuf->sysfs_entry = sysfs_entry; + + /* create the directory for buffer stats */ + ret = kobject_init_and_add(&sysfs_entry->kobj, &dma_buf_ktype, NULL, + "%lu", file_inode(dmabuf->file)->i_ino); + if (ret) + goto err_sysfs_dmabuf; + + /* create the directory for attachment stats */ + attach_stats_kset = kset_create_and_add("attachments", + &dmabuf_sysfs_no_uevent_ops, + &sysfs_entry->kobj); + if (!attach_stats_kset) { + ret = -ENOMEM; + goto err_sysfs_attach; + } + + sysfs_entry->attach_stats_kset = attach_stats_kset; + + return 0; + +err_sysfs_attach: + kobject_del(&sysfs_entry->kobj); +err_sysfs_dmabuf: + kobject_put(&sysfs_entry->kobj); + dmabuf->sysfs_entry = NULL; + return ret; +} diff --git a/drivers/dma-buf/dma-buf-sysfs-stats.h b/drivers/dma-buf/dma-buf-sysfs-stats.h new file mode 100644 index 000000000000..5f4703249117 --- /dev/null +++ b/drivers/dma-buf/dma-buf-sysfs-stats.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * DMA-BUF sysfs statistics. + * + * Copyright (C) 2021 Google LLC. + */ + +#ifndef _DMA_BUF_SYSFS_STATS_H +#define _DMA_BUF_SYSFS_STATS_H + +#ifdef CONFIG_DMABUF_SYSFS_STATS + +int dma_buf_init_sysfs_statistics(void); +void dma_buf_uninit_sysfs_statistics(void); + +int dma_buf_stats_setup(struct dma_buf *dmabuf); +int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach, + unsigned int uid); +static inline void dma_buf_update_attachment_map_count(struct dma_buf_attachment *attach, + int delta) +{ + struct dma_buf_attach_sysfs_entry *entry = attach->sysfs_entry; + + entry->map_counter += delta; +} +void dma_buf_stats_teardown(struct dma_buf *dmabuf); +void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach); +static inline unsigned int dma_buf_update_attach_uid(struct dma_buf *dmabuf) +{ + struct dma_buf_sysfs_entry *entry = dmabuf->sysfs_entry; + + return entry->attachment_uid++; +} +#else + +static inline int dma_buf_init_sysfs_statistics(void) +{ + return 0; +} + +static inline void dma_buf_uninit_sysfs_statistics(void) {} + +static inline int dma_buf_stats_setup(struct dma_buf *dmabuf) +{ + return 0; +} +static inline int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach, + unsigned int uid) +{ + return 0; +} + +static inline void dma_buf_stats_teardown(struct dma_buf *dmabuf) {} +static inline void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach) {} +static inline void dma_buf_update_attachment_map_count(struct dma_buf_attachment *attach, + int delta) {} +static inline unsigned int dma_buf_update_attach_uid(struct dma_buf *dmabuf) +{ + return 0; +} +#endif +#endif // _DMA_BUF_SYSFS_STATS_H diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 511fe0d217a0..d0121402c58c 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -29,6 +29,8 @@ #include #include +#include "dma-buf-sysfs-stats.h" + static inline int is_dma_buf_file(struct file *); struct dma_buf_list { @@ -79,6 +81,7 @@ static void dma_buf_release(struct dentry *dentry) if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) dma_resv_fini(dmabuf->resv); + dma_buf_stats_teardown(dmabuf); module_put(dmabuf->owner); kfree(dmabuf->name); kfree(dmabuf); @@ -580,6 +583,10 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) file->f_mode |= FMODE_LSEEK; dmabuf->file = file; + ret = dma_buf_stats_setup(dmabuf); + if (ret) + goto err_sysfs; + mutex_init(&dmabuf->lock); INIT_LIST_HEAD(&dmabuf->attachments); @@ -589,6 +596,14 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) return dmabuf; +err_sysfs: + /* + * Set file->f_path.dentry->d_fsdata to NULL so that when + * dma_buf_release() gets invoked by dentry_ops, it exits + * early before calling the release() dma_buf op. + */ + file->f_path.dentry->d_fsdata = NULL; + fput(file); err_dmabuf: kfree(dmabuf); err_module: @@ -723,6 +738,7 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, { struct dma_buf_attachment *attach; int ret; + unsigned int attach_uid; if (WARN_ON(!dmabuf || !dev)) return ERR_PTR(-EINVAL); @@ -748,8 +764,13 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, } dma_resv_lock(dmabuf->resv, NULL); list_add(&attach->node, &dmabuf->attachments); + attach_uid = dma_buf_update_attach_uid(dmabuf); dma_resv_unlock(dmabuf->resv); + ret = dma_buf_attach_stats_setup(attach, attach_uid); + if (ret) + goto err_sysfs; + /* When either the importer or the exporter can't handle dynamic * mappings we cache the mapping here to avoid issues with the * reservation object lock. @@ -776,6 +797,7 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, dma_resv_unlock(attach->dmabuf->resv); attach->sgt = sgt; attach->dir = DMA_BIDIRECTIONAL; + dma_buf_update_attachment_map_count(attach, 1 /* delta */); } return attach; @@ -792,6 +814,7 @@ err_unlock: if (dma_buf_is_dynamic(attach->dmabuf)) dma_resv_unlock(attach->dmabuf->resv); +err_sysfs: dma_buf_detach(dmabuf, attach); return ERR_PTR(ret); } @@ -841,6 +864,7 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) dma_resv_lock(attach->dmabuf->resv, NULL); __unmap_dma_buf(attach, attach->sgt, attach->dir); + dma_buf_update_attachment_map_count(attach, -1 /* delta */); if (dma_buf_is_dynamic(attach->dmabuf)) { dmabuf->ops->unpin(attach); @@ -854,6 +878,7 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) if (dmabuf->ops->detach) dmabuf->ops->detach(dmabuf, attach); + dma_buf_attach_stats_teardown(attach); kfree(attach); } EXPORT_SYMBOL_GPL(dma_buf_detach); @@ -993,6 +1018,9 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, } #endif /* CONFIG_DMA_API_DEBUG */ + if (!IS_ERR(sg_table)) + dma_buf_update_attachment_map_count(attach, 1 /* delta */); + return sg_table; } EXPORT_SYMBOL_GPL(dma_buf_map_attachment); @@ -1030,6 +1058,8 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, if (dma_buf_is_dynamic(attach->dmabuf) && !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) dma_buf_unpin(attach); + + dma_buf_update_attachment_map_count(attach, -1 /* delta */); } EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); @@ -1469,6 +1499,12 @@ static inline void dma_buf_uninit_debugfs(void) static int __init dma_buf_init(void) { + int ret; + + ret = dma_buf_init_sysfs_statistics(); + if (ret) + return ret; + dma_buf_mnt = kern_mount(&dma_buf_fs_type); if (IS_ERR(dma_buf_mnt)) return PTR_ERR(dma_buf_mnt); @@ -1484,5 +1520,6 @@ static void __exit dma_buf_deinit(void) { dma_buf_uninit_debugfs(); kern_unmount(dma_buf_mnt); + dma_buf_uninit_sysfs_statistics(); } __exitcall(dma_buf_deinit); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index efdc56b9d95f..342585bd6dff 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -295,6 +295,9 @@ struct dma_buf_ops { * @poll: for userspace poll support * @cb_excl: for userspace poll support * @cb_shared: for userspace poll support + * @sysfs_entry: for exposing information about this buffer in sysfs. + * The attachment_uid member of @sysfs_entry is protected by dma_resv lock + * and is incremented on each attach. * * This represents a shared buffer, created by calling dma_buf_export(). The * userspace representation is a normal file descriptor, which can be created by @@ -330,6 +333,15 @@ struct dma_buf { __poll_t active; } cb_excl, cb_shared; +#ifdef CONFIG_DMABUF_SYSFS_STATS + /* for sysfs stats */ + struct dma_buf_sysfs_entry { + struct kobject kobj; + struct dma_buf *dmabuf; + unsigned int attachment_uid; + struct kset *attach_stats_kset; + } *sysfs_entry; +#endif }; /** @@ -379,6 +391,7 @@ struct dma_buf_attach_ops { * @importer_ops: importer operations for this attachment, if provided * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held. * @importer_priv: importer specific attachment data. + * @sysfs_entry: For exposing information about this attachment in sysfs. * * This structure holds the attachment information between the dma_buf buffer * and its user device(s). The list contains one attachment struct per device @@ -399,6 +412,13 @@ struct dma_buf_attachment { const struct dma_buf_attach_ops *importer_ops; void *importer_priv; void *priv; +#ifdef CONFIG_DMABUF_SYSFS_STATS + /* for sysfs stats */ + struct dma_buf_attach_sysfs_entry { + struct kobject kobj; + unsigned int map_counter; + } *sysfs_entry; +#endif }; /** -- cgit v1.2.3 From 89bcadc8f94bd6e6361b5c803ec6f40132e8bace Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Mon, 21 Jun 2021 17:17:58 +0200 Subject: dma-buf: Document non-dynamic exporter expectations better MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Christian and me realized we have a pretty massive disconnect about different interpretations of what dma_resv is used for by different drivers. The discussion is much, much bigger than this change here, but this is an important one: Non-dynamic exporters must guarantee that the memory they return is ready for use. They cannot expect importers to wait for the exclusive fence. Only dynamic importers are required to obey the dma_resv fences strictly (and more patches are needed to define exactly what this means). Christian has patches to update nouvea, radeon and amdgpu. The only other driver using both ttm and supporting dma-buf export is qxl, which only uses synchronous ttm_bo_move. v2: To hammer this in document that dynamic importers _must_ wait for the exclusive fence after having called dma_buf_map_attachment. Reviewed-by: Christian König Cc: Christian König Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210621151758.2347474-1-daniel.vetter@ffwll.ch --- drivers/dma-buf/dma-buf.c | 3 +++ include/linux/dma-buf.h | 15 +++++++++++++++ 2 files changed, 18 insertions(+) (limited to 'include/linux') diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index d0121402c58c..510b42771974 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -951,6 +951,9 @@ EXPORT_SYMBOL_GPL(dma_buf_unpin); * the underlying backing storage is pinned for as long as a mapping exists, * therefore users/importers should not hold onto a mapping for undue amounts of * time. + * + * Important: Dynamic importers must wait for the exclusive fence of the struct + * dma_resv attached to the DMA-BUF first. */ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, enum dma_data_direction direction) diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 342585bd6dff..92eec38a03aa 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -96,6 +96,12 @@ struct dma_buf_ops { * This is called automatically for non-dynamic importers from * dma_buf_attach(). * + * Note that similar to non-dynamic exporters in their @map_dma_buf + * callback the driver must guarantee that the memory is available for + * use and cleared of any old data by the time this function returns. + * Drivers which pipeline their buffer moves internally must wait for + * all moves and clears to complete. + * * Returns: * * 0 on success, negative error code on failure. @@ -144,6 +150,15 @@ struct dma_buf_ops { * This is always called with the dmabuf->resv object locked when * the dynamic_mapping flag is true. * + * Note that for non-dynamic exporters the driver must guarantee that + * that the memory is available for use and cleared of any old data by + * the time this function returns. Drivers which pipeline their buffer + * moves internally must wait for all moves and clears to complete. + * Dynamic exporters do not need to follow this rule: For non-dynamic + * importers the buffer is already pinned through @pin, which has the + * same requirements. Dynamic importers otoh are required to obey the + * dma_resv fences. + * * Returns: * * A &sg_table scatter list of or the backing storage of the DMA buffer, -- cgit v1.2.3 From 2254e49cef7015d7697bd1617d19e620e2788ec5 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 22 Jun 2021 18:54:57 +0200 Subject: dma-resv: Fix kerneldoc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Oversight from commit 6edbd6abb783d54f6ac4c3ed5cd9e50cff6c15e9 Author: Christian König Date: Mon May 10 16:14:09 2021 +0200 dma-buf: rename and cleanup dma_resv_get_excl v3 Reviewed-by: Alex Deucher Reviewed-by: Christian König Signed-off-by: Daniel Vetter Cc: Sumit Semwal Cc: "Christian König" Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210622165511.3169559-2-daniel.vetter@ffwll.ch --- include/linux/dma-resv.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 562b885cf9c3..e1ca2080a1ff 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -212,7 +212,7 @@ static inline void dma_resv_unlock(struct dma_resv *obj) } /** - * dma_resv_exclusive - return the object's exclusive fence + * dma_resv_excl_fence - return the object's exclusive fence * @obj: the reservation object * * Returns the exclusive fence (if any). Caller must either hold the objects -- cgit v1.2.3 From d6abed2ad168dbc3f9aac986b3b89ba6d3535e01 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 23 Jun 2021 18:17:12 +0200 Subject: dma-buf: Switch to inline kerneldoc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Also review & update everything while we're at it. This is prep work to smash a ton of stuff into the kerneldoc for @resv. v2: Move the doc for sysfs_entry.attachment_uid to the right place too (Sam) Reviewed-by: Sam Ravnborg Acked-by: Christian König Cc: Sam Ravnborg Reviewed-by: Alex Deucher Signed-off-by: Daniel Vetter Cc: Sumit Semwal Cc: "Christian König" Cc: Alex Deucher Cc: Daniel Vetter Cc: Dave Airlie Cc: Nirmoy Das Cc: Deepak R Varma Cc: Chen Li Cc: Kevin Wang Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20210623161712.3370885-1-daniel.vetter@ffwll.ch --- include/linux/dma-buf.h | 116 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 90 insertions(+), 26 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 92eec38a03aa..81cebf414505 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -289,30 +289,6 @@ struct dma_buf_ops { /** * struct dma_buf - shared buffer object - * @size: size of the buffer; invariant over the lifetime of the buffer. - * @file: file pointer used for sharing buffers across, and for refcounting. - * @attachments: list of dma_buf_attachment that denotes all devices attached, - * protected by dma_resv lock. - * @ops: dma_buf_ops associated with this buffer object. - * @lock: used internally to serialize list manipulation, attach/detach and - * vmap/unmap - * @vmapping_counter: used internally to refcnt the vmaps - * @vmap_ptr: the current vmap ptr if vmapping_counter > 0 - * @exp_name: name of the exporter; useful for debugging. - * @name: userspace-provided name; useful for accounting and debugging, - * protected by @resv. - * @name_lock: spinlock to protect name access - * @owner: pointer to exporter module; used for refcounting when exporter is a - * kernel module. - * @list_node: node for dma_buf accounting and debugging. - * @priv: exporter specific private data for this buffer object. - * @resv: reservation object linked to this dma-buf - * @poll: for userspace poll support - * @cb_excl: for userspace poll support - * @cb_shared: for userspace poll support - * @sysfs_entry: for exposing information about this buffer in sysfs. - * The attachment_uid member of @sysfs_entry is protected by dma_resv lock - * and is incremented on each attach. * * This represents a shared buffer, created by calling dma_buf_export(). The * userspace representation is a normal file descriptor, which can be created by @@ -324,24 +300,100 @@ struct dma_buf_ops { * Device DMA access is handled by the separate &struct dma_buf_attachment. */ struct dma_buf { + /** + * @size: + * + * Size of the buffer; invariant over the lifetime of the buffer. + */ size_t size; + + /** + * @file: + * + * File pointer used for sharing buffers across, and for refcounting. + * See dma_buf_get() and dma_buf_put(). + */ struct file *file; + + /** + * @attachments: + * + * List of dma_buf_attachment that denotes all devices attached, + * protected by &dma_resv lock @resv. + */ struct list_head attachments; + + /** @ops: dma_buf_ops associated with this buffer object. */ const struct dma_buf_ops *ops; + + /** + * @lock: + * + * Used internally to serialize list manipulation, attach/detach and + * vmap/unmap. Note that in many cases this is superseeded by + * dma_resv_lock() on @resv. + */ struct mutex lock; + + /** + * @vmapping_counter: + * + * Used internally to refcnt the vmaps returned by dma_buf_vmap(). + * Protected by @lock. + */ unsigned vmapping_counter; + + /** + * @vmap_ptr: + * The current vmap ptr if @vmapping_counter > 0. Protected by @lock. + */ struct dma_buf_map vmap_ptr; + + /** + * @exp_name: + * + * Name of the exporter; useful for debugging. See the + * DMA_BUF_SET_NAME IOCTL. + */ const char *exp_name; + + /** + * @name: + * + * Userspace-provided name; useful for accounting and debugging, + * protected by dma_resv_lock() on @resv and @name_lock for read access. + */ const char *name; + + /** @name_lock: Spinlock to protect name acces for read access. */ spinlock_t name_lock; + + /** + * @owner: + * + * Pointer to exporter module; used for refcounting when exporter is a + * kernel module. + */ struct module *owner; + + /** @list_node: node for dma_buf accounting and debugging. */ struct list_head list_node; + + /** @priv: exporter specific private data for this buffer object. */ void *priv; + + /** + * @resv: + * + * Reservation object linked to this dma-buf. + */ struct dma_resv *resv; - /* poll support */ + /** @poll: for userspace poll support */ wait_queue_head_t poll; + /** @cb_excl: for userspace poll support */ + /** @cb_shared: for userspace poll support */ struct dma_buf_poll_cb_t { struct dma_fence_cb cb; wait_queue_head_t *poll; @@ -349,10 +401,22 @@ struct dma_buf { __poll_t active; } cb_excl, cb_shared; #ifdef CONFIG_DMABUF_SYSFS_STATS - /* for sysfs stats */ + /** + * @sysfs_entry: + * + * For exposing information about this buffer in sysfs. See also + * `DMA-BUF statistics`_ for the uapi this enables. + */ struct dma_buf_sysfs_entry { struct kobject kobj; struct dma_buf *dmabuf; + + /** + * @sysfs_entry.attachment_uid: + * + * This is protected by the dma_resv_lock() on @resv and is + * incremented on each attach. + */ unsigned int attachment_uid; struct kset *attach_stats_kset; } *sysfs_entry; -- cgit v1.2.3 From 05459351ce307f6ba0e0221968b1e15b97d3b075 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 24 Jun 2021 14:52:46 +0200 Subject: dma-buf: Document dma-buf implicit fencing/resv fencing rules MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Docs for struct dma_resv are fairly clear: "A reservation object can have attached one exclusive fence (normally associated with write operations) or N shared fences (read operations)." https://dri.freedesktop.org/docs/drm/driver-api/dma-buf.html#reservation-objects Furthermore a review across all of upstream. First of render drivers and how they set implicit fences: - nouveau follows this contract, see in validate_fini_no_ticket() nouveau_bo_fence(nvbo, fence, !!b->write_domains); and that last boolean controls whether the exclusive or shared fence slot is used. - radeon follows this contract by setting p->relocs[i].tv.num_shared = !r->write_domain; in radeon_cs_parser_relocs(), which ensures that the call to ttm_eu_fence_buffer_objects() in radeon_cs_parser_fini() will do the right thing. - vmwgfx seems to follow this contract with the shotgun approach of always setting ttm_val_buf->num_shared = 0, which means ttm_eu_fence_buffer_objects() will only use the exclusive slot. - etnaviv follows this contract, as can be trivially seen by looking at submit_attach_object_fences() - i915 is a bit a convoluted maze with multiple paths leading to i915_vma_move_to_active(). Which sets the exclusive flag if EXEC_OBJECT_WRITE is set. This can either come as a buffer flag for softpin mode, or through the write_domain when using relocations. It follows this contract. - lima follows this contract, see lima_gem_submit() which sets the exclusive fence when the LIMA_SUBMIT_BO_WRITE flag is set for that bo - msm follows this contract, see msm_gpu_submit() which sets the exclusive flag when the MSM_SUBMIT_BO_WRITE is set for that buffer - panfrost follows this contract with the shotgun approach of just always setting the exclusive fence, see panfrost_attach_object_fences(). Benefits of a single engine I guess - v3d follows this contract with the same shotgun approach in v3d_attach_fences_and_unlock_reservation(), but it has at least an XXX comment that maybe this should be improved - v4c uses the same shotgun approach of always setting an exclusive fence, see vc4_update_bo_seqnos() - vgem also follows this contract, see vgem_fence_attach_ioctl() and the VGEM_FENCE_WRITE. This is used in some igts to validate prime sharing with i915.ko without the need of a 2nd gpu - vritio follows this contract again with the shotgun approach of always setting an exclusive fence, see virtio_gpu_array_add_fence() This covers the setting of the exclusive fences when writing. Synchronizing against the exclusive fence is a lot more tricky, and I only spot checked a few: - i915 does it, with the optional EXEC_OBJECT_ASYNC to skip all implicit dependencies (which is used by vulkan) - etnaviv does this. Implicit dependencies are collected in submit_fence_sync(), again with an opt-out flag ETNA_SUBMIT_NO_IMPLICIT. These are then picked up in etnaviv_sched_dependency which is the drm_sched_backend_ops->dependency callback. - v4c seems to not do much here, maybe gets away with it by not having a scheduler and only a single engine. Since all newer broadcom chips than the OG vc4 use v3d for rendering, which follows this contract, the impact of this issue is fairly small. - v3d does this using the drm_gem_fence_array_add_implicit() helper, which then it's drm_sched_backend_ops->dependency callback v3d_job_dependency() picks up. - panfrost is nice here and tracks the implicit fences in panfrost_job->implicit_fences, which again the drm_sched_backend_ops->dependency callback panfrost_job_dependency() picks up. It is mildly questionable though since it only picks up exclusive fences in panfrost_acquire_object_fences(), but not buggy in practice because it also always sets the exclusive fence. It should pick up both sets of fences, just in case there's ever going to be a 2nd gpu in a SoC with a mali gpu. Or maybe a mali SoC with a pcie port and a real gpu, which might actually happen eventually. A bug, but easy to fix. Should probably use the drm_gem_fence_array_add_implicit() helper. - lima is nice an easy, uses drm_gem_fence_array_add_implicit() and the same schema as v3d. - msm is mildly entertaining. It also supports MSM_SUBMIT_NO_IMPLICIT, but because it doesn't use the drm/scheduler it handles fences from the wrong context with a synchronous dma_fence_wait. See submit_fence_sync() leading to msm_gem_sync_object(). Investing into a scheduler might be a good idea. - all the remaining drivers are ttm based, where I hope they do appropriately obey implicit fences already. I didn't do the full audit there because a) not follow the contract would confuse ttm quite well and b) reading non-standard scheduler and submit code which isn't based on drm/scheduler is a pain. Onwards to the display side. - Any driver using the drm_gem_plane_helper_prepare_fb() helper will correctly. Overwhelmingly most drivers get this right, except a few totally dont. I'll follow up with a patch to make this the default and avoid a bunch of bugs. - I didn't audit the ttm drivers, but given that dma_resv started there I hope they get this right. In conclusion this IS the contract, both as documented and overwhelmingly implemented, specically as implemented by all render drivers except amdgpu. Amdgpu tried to fix this already in commit 049aca4363d8af87cab8d53de5401602db3b9999 Author: Christian König Date: Wed Sep 19 16:54:35 2018 +0200 drm/amdgpu: fix using shared fence for exported BOs v2 but this fix falls short on a number of areas: - It's racy, by the time the buffer is shared it might be too late. To make sure there's definitely never a problem we need to set the fences correctly for any buffer that's potentially exportable. - It's breaking uapi, dma-buf fds support poll() and differentitiate between, which was introduced in commit 9b495a5887994a6d74d5c261d012083a92b94738 Author: Maarten Lankhorst Date: Tue Jul 1 12:57:43 2014 +0200 dma-buf: add poll support, v3 - Christian König wants to nack new uapi building further on this dma_resv contract because it breaks amdgpu, quoting "Yeah, and that is exactly the reason why I will NAK this uAPI change. "This doesn't works for amdgpu at all for the reasons outlined above." https://lore.kernel.org/dri-devel/f2eb6751-2f82-9b23-f57e-548de5b729de@gmail.com/ Rejecting new development because your own driver is broken and violates established cross driver contracts and uapi is really not how upstream works. Now this patch will have a severe performance impact on anything that runs on multiple engines. So we can't just merge it outright, but need a bit a plan: - amdgpu needs a proper uapi for handling implicit fencing. The funny thing is that to do it correctly, implicit fencing must be treated as a very strange IPC mechanism for transporting fences, where both setting the fence and dependency intercepts must be handled explicitly. Current best practices is a per-bo flag to indicate writes, and a per-bo flag to to skip implicit fencing in the CS ioctl as a new chunk. - Since amdgpu has been shipping with broken behaviour we need an opt-out flag from the butchered implicit fencing model to enable the proper explicit implicit fencing model. - for kernel memory fences due to bo moves at least the i915 idea is to use ttm_bo->moving. amdgpu probably needs the same. - since the current p2p dma-buf interface assumes the kernel memory fence is in the exclusive dma_resv fence slot we need to add a new fence slot for kernel fences, which must never be ignored. Since currently only amdgpu supports this there's no real problem here yet, until amdgpu gains a NO_IMPLICIT CS flag. - New userspace needs to ship in enough desktop distros so that users wont notice the perf impact. I think we can ignore LTS distros who upgrade their kernels but not their mesa3d snapshot. - Then when this is all in place we can merge this patch here. What is not a solution to this problem here is trying to make the dma_resv rules in the kernel more clever. The fundamental issue here is that the amdgpu CS uapi is the least expressive one across all drivers (only equalled by panfrost, which has an actual excuse) by not allowing any userspace control over how implicit sync is conducted. Until this is fixed it's completely pointless to make the kernel more clever to improve amdgpu, because all we're doing is papering over this uapi design issue. amdgpu needs to attain the status quo established by other drivers first, once that's achieved we can tackle the remaining issues in a consistent way across drivers. v2: Bas pointed me at AMDGPU_GEM_CREATE_EXPLICIT_SYNC, which I entirely missed. This is great because it means the amdgpu specific piece for proper implicit fence handling exists already, and that since a while. The only thing that's now missing is - fishing the implicit fences out of a shared object at the right time - setting the exclusive implicit fence slot at the right time. Jason has a patch series to fill that gap with a bunch of generic ioctl on the dma-buf fd: https://lore.kernel.org/dri-devel/20210520190007.534046-1-jason@jlekstrand.net/ v3: Since Christian has fixed amdgpu now in commit 8c505bdc9c8b955223b054e34a0be9c3d841cd20 (drm-misc/drm-misc-next) Author: Christian König Date: Wed Jun 9 13:51:36 2021 +0200 drm/amdgpu: rework dma_resv handling v3 Use the audit covered in this commit message as the excuse to update the dma-buf docs around dma_buf.resv usage across drivers. Since dynamic importers have different rules also hammer these in again while we're at it. v4: - Add the missing "through the device" in the dynamic section that I overlooked. - Fix a kerneldoc markup mistake, the link didn't connect v5: - A few s/should/must/ to make clear what must be done (if the driver does implicit sync) and what's more a maybe (Daniel Stone) - drop all the example api discussion, that needs to be expanded, clarified and put into a new chapter in drm-uapi.rst (Daniel Stone) Cc: Daniel Stone Acked-by: Daniel Stone Reviewed-by: Dave Airlie (v4) Reviewed-by: Christian König (v3) Cc: mesa-dev@lists.freedesktop.org Cc: Bas Nieuwenhuizen Cc: Dave Airlie Cc: Rob Clark Cc: Kristian H. Kristensen Cc: Michel Dänzer Cc: Daniel Stone Cc: Sumit Semwal Cc: "Christian König" Cc: Alex Deucher Cc: Daniel Vetter Cc: Deepak R Varma Cc: Chen Li Cc: Kevin Wang Cc: Dennis Li Cc: Luben Tuikov Cc: linaro-mm-sig@lists.linaro.org Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210624125246.166721-1-daniel.vetter@ffwll.ch --- include/linux/dma-buf.h | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'include/linux') diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 81cebf414505..2b814fde0d11 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -386,6 +386,40 @@ struct dma_buf { * @resv: * * Reservation object linked to this dma-buf. + * + * IMPLICIT SYNCHRONIZATION RULES: + * + * Drivers which support implicit synchronization of buffer access as + * e.g. exposed in `Implicit Fence Poll Support`_ must follow the + * below rules. + * + * - Drivers must add a shared fence through dma_resv_add_shared_fence() + * for anything the userspace API considers a read access. This highly + * depends upon the API and window system. + * + * - Similarly drivers must set the exclusive fence through + * dma_resv_add_excl_fence() for anything the userspace API considers + * write access. + * + * - Drivers may just always set the exclusive fence, since that only + * causes unecessarily synchronization, but no correctness issues. + * + * - Some drivers only expose a synchronous userspace API with no + * pipelining across drivers. These do not set any fences for their + * access. An example here is v4l. + * + * DYNAMIC IMPORTER RULES: + * + * Dynamic importers, see dma_buf_attachment_is_dynamic(), have + * additional constraints on how they set up fences: + * + * - Dynamic importers must obey the exclusive fence and wait for it to + * signal before allowing access to the buffer's underlying storage + * through the device. + * + * - Dynamic importers should set fences for any access that they can't + * disable immediately from their &dma_buf_attach_ops.move_notify + * callback. */ struct dma_resv *resv; -- cgit v1.2.3 From 0189cb57b96ff92f75e3680b3710a46dacd6509f Mon Sep 17 00:00:00 2001 From: Xiyu Yang Date: Mon, 19 Jul 2021 13:59:45 +0800 Subject: fbmem: Convert from atomic_t to refcount_t on fb_info->count refcount_t type and corresponding API can protect refcounters from accidental underflow and overflow and further use-after-free situations. Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/1626674392-55857-1-git-send-email-xiyuyang19@fudan.edu.cn --- drivers/video/fbdev/core/fbmem.c | 6 +++--- include/linux/fb.h | 3 ++- 2 files changed, 5 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 072780b0e570..1598736e3bcf 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -67,7 +67,7 @@ static struct fb_info *get_fb_info(unsigned int idx) mutex_lock(®istration_lock); fb_info = registered_fb[idx]; if (fb_info) - atomic_inc(&fb_info->count); + refcount_inc(&fb_info->count); mutex_unlock(®istration_lock); return fb_info; @@ -75,7 +75,7 @@ static struct fb_info *get_fb_info(unsigned int idx) static void put_fb_info(struct fb_info *fb_info) { - if (!atomic_dec_and_test(&fb_info->count)) + if (!refcount_dec_and_test(&fb_info->count)) return; if (fb_info->fbops->fb_destroy) fb_info->fbops->fb_destroy(fb_info); @@ -1590,7 +1590,7 @@ static int do_register_framebuffer(struct fb_info *fb_info) if (!registered_fb[i]) break; fb_info->node = i; - atomic_set(&fb_info->count, 1); + refcount_set(&fb_info->count, 1); mutex_init(&fb_info->lock); mutex_init(&fb_info->mm_lock); diff --git a/include/linux/fb.h b/include/linux/fb.h index a8dccd23c249..9023739e9a42 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -2,6 +2,7 @@ #ifndef _LINUX_FB_H #define _LINUX_FB_H +#include #include #include @@ -435,7 +436,7 @@ struct fb_tile_ops { struct fb_info { - atomic_t count; + refcount_t count; int node; int flags; /* -- cgit v1.2.3 From c715def51591a874a9fcfdc9a05d543e8797e697 Mon Sep 17 00:00:00 2001 From: Hridya Valsaraju Date: Mon, 12 Jul 2021 21:07:38 -0700 Subject: dma-buf: Delete the DMA-BUF attachment sysfs statistics MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The DMA-BUF attachment statistics form a subset of the DMA-BUF sysfs statistics that recently merged to the drm-misc tree. They are not UABI yet since they have not merged to the upstream Linux kernel. Since there has been a reported a performance regression due to the overhead of sysfs directory creation/teardown during dma_buf_attach()/dma_buf_detach(), this patch deletes the DMA-BUF attachment statistics from sysfs. Fixes: bdb8d06dfefd ("dmabuf: Add the capability to expose DMA-BUF stats in sysfs") Signed-off-by: Hridya Valsaraju Reviewed-by: Christian König Reviewed-by: Greg Kroah-Hartman Link: https://patchwork.freedesktop.org/patch/msgid/20210713040742.2680135-1-hridya@google.com Signed-off-by: Christian König --- .../ABI/testing/sysfs-kernel-dmabuf-buffers | 28 ----- drivers/dma-buf/dma-buf-sysfs-stats.c | 140 +-------------------- drivers/dma-buf/dma-buf-sysfs-stats.h | 27 ---- drivers/dma-buf/dma-buf.c | 16 --- include/linux/dma-buf.h | 17 --- 5 files changed, 4 insertions(+), 224 deletions(-) (limited to 'include/linux') diff --git a/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers b/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers index a243984ed420..5d3bc997dc64 100644 --- a/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers +++ b/Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers @@ -22,31 +22,3 @@ KernelVersion: v5.13 Contact: Hridya Valsaraju Description: This file is read-only and specifies the size of the DMA-BUF in bytes. - -What: /sys/kernel/dmabuf/buffers//attachments -Date: May 2021 -KernelVersion: v5.13 -Contact: Hridya Valsaraju -Description: This directory will contain subdirectories representing every - attachment of the DMA-BUF. - -What: /sys/kernel/dmabuf/buffers//attachments/ -Date: May 2021 -KernelVersion: v5.13 -Contact: Hridya Valsaraju -Description: This directory will contain information on the attached device - and the number of current distinct device mappings. - -What: /sys/kernel/dmabuf/buffers//attachments//device -Date: May 2021 -KernelVersion: v5.13 -Contact: Hridya Valsaraju -Description: This file is read-only and is a symlink to the attached device's - sysfs entry. - -What: /sys/kernel/dmabuf/buffers//attachments//map_counter -Date: May 2021 -KernelVersion: v5.13 -Contact: Hridya Valsaraju -Description: This file is read-only and contains a map_counter indicating the - number of distinct device mappings of the attachment. diff --git a/drivers/dma-buf/dma-buf-sysfs-stats.c b/drivers/dma-buf/dma-buf-sysfs-stats.c index a2638e84199c..053baadcada9 100644 --- a/drivers/dma-buf/dma-buf-sysfs-stats.c +++ b/drivers/dma-buf/dma-buf-sysfs-stats.c @@ -40,14 +40,11 @@ * * * ``/sys/kernel/dmabuf/buffers//exporter_name`` * * ``/sys/kernel/dmabuf/buffers//size`` - * * ``/sys/kernel/dmabuf/buffers//attachments//device`` - * * ``/sys/kernel/dmabuf/buffers//attachments//map_counter`` * - * The information in the interface can also be used to derive per-exporter and - * per-device usage statistics. The data from the interface can be gathered - * on error conditions or other important events to provide a snapshot of - * DMA-BUF usage. It can also be collected periodically by telemetry to monitor - * various metrics. + * The information in the interface can also be used to derive per-exporter + * statistics. The data from the interface can be gathered on error conditions + * or other important events to provide a snapshot of DMA-BUF usage. + * It can also be collected periodically by telemetry to monitor various metrics. * * Detailed documentation about the interface is present in * Documentation/ABI/testing/sysfs-kernel-dmabuf-buffers. @@ -121,120 +118,6 @@ static struct kobj_type dma_buf_ktype = { .default_groups = dma_buf_stats_default_groups, }; -#define to_dma_buf_attach_entry_from_kobj(x) container_of(x, struct dma_buf_attach_sysfs_entry, kobj) - -struct dma_buf_attach_stats_attribute { - struct attribute attr; - ssize_t (*show)(struct dma_buf_attach_sysfs_entry *sysfs_entry, - struct dma_buf_attach_stats_attribute *attr, char *buf); -}; -#define to_dma_buf_attach_stats_attr(x) container_of(x, struct dma_buf_attach_stats_attribute, attr) - -static ssize_t dma_buf_attach_stats_attribute_show(struct kobject *kobj, - struct attribute *attr, - char *buf) -{ - struct dma_buf_attach_stats_attribute *attribute; - struct dma_buf_attach_sysfs_entry *sysfs_entry; - - attribute = to_dma_buf_attach_stats_attr(attr); - sysfs_entry = to_dma_buf_attach_entry_from_kobj(kobj); - - if (!attribute->show) - return -EIO; - - return attribute->show(sysfs_entry, attribute, buf); -} - -static const struct sysfs_ops dma_buf_attach_stats_sysfs_ops = { - .show = dma_buf_attach_stats_attribute_show, -}; - -static ssize_t map_counter_show(struct dma_buf_attach_sysfs_entry *sysfs_entry, - struct dma_buf_attach_stats_attribute *attr, - char *buf) -{ - return sysfs_emit(buf, "%u\n", sysfs_entry->map_counter); -} - -static struct dma_buf_attach_stats_attribute map_counter_attribute = - __ATTR_RO(map_counter); - -static struct attribute *dma_buf_attach_stats_default_attrs[] = { - &map_counter_attribute.attr, - NULL, -}; -ATTRIBUTE_GROUPS(dma_buf_attach_stats_default); - -static void dma_buf_attach_sysfs_release(struct kobject *kobj) -{ - struct dma_buf_attach_sysfs_entry *sysfs_entry; - - sysfs_entry = to_dma_buf_attach_entry_from_kobj(kobj); - kfree(sysfs_entry); -} - -static struct kobj_type dma_buf_attach_ktype = { - .sysfs_ops = &dma_buf_attach_stats_sysfs_ops, - .release = dma_buf_attach_sysfs_release, - .default_groups = dma_buf_attach_stats_default_groups, -}; - -void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach) -{ - struct dma_buf_attach_sysfs_entry *sysfs_entry; - - sysfs_entry = attach->sysfs_entry; - if (!sysfs_entry) - return; - - sysfs_delete_link(&sysfs_entry->kobj, &attach->dev->kobj, "device"); - - kobject_del(&sysfs_entry->kobj); - kobject_put(&sysfs_entry->kobj); -} - -int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach, - unsigned int uid) -{ - struct dma_buf_attach_sysfs_entry *sysfs_entry; - int ret; - struct dma_buf *dmabuf; - - if (!attach) - return -EINVAL; - - dmabuf = attach->dmabuf; - - sysfs_entry = kzalloc(sizeof(struct dma_buf_attach_sysfs_entry), - GFP_KERNEL); - if (!sysfs_entry) - return -ENOMEM; - - sysfs_entry->kobj.kset = dmabuf->sysfs_entry->attach_stats_kset; - - attach->sysfs_entry = sysfs_entry; - - ret = kobject_init_and_add(&sysfs_entry->kobj, &dma_buf_attach_ktype, - NULL, "%u", uid); - if (ret) - goto kobj_err; - - ret = sysfs_create_link(&sysfs_entry->kobj, &attach->dev->kobj, - "device"); - if (ret) - goto link_err; - - return 0; - -link_err: - kobject_del(&sysfs_entry->kobj); -kobj_err: - kobject_put(&sysfs_entry->kobj); - attach->sysfs_entry = NULL; - - return ret; -} void dma_buf_stats_teardown(struct dma_buf *dmabuf) { struct dma_buf_sysfs_entry *sysfs_entry; @@ -243,7 +126,6 @@ void dma_buf_stats_teardown(struct dma_buf *dmabuf) if (!sysfs_entry) return; - kset_unregister(sysfs_entry->attach_stats_kset); kobject_del(&sysfs_entry->kobj); kobject_put(&sysfs_entry->kobj); } @@ -290,7 +172,6 @@ int dma_buf_stats_setup(struct dma_buf *dmabuf) { struct dma_buf_sysfs_entry *sysfs_entry; int ret; - struct kset *attach_stats_kset; if (!dmabuf || !dmabuf->file) return -EINVAL; @@ -315,21 +196,8 @@ int dma_buf_stats_setup(struct dma_buf *dmabuf) if (ret) goto err_sysfs_dmabuf; - /* create the directory for attachment stats */ - attach_stats_kset = kset_create_and_add("attachments", - &dmabuf_sysfs_no_uevent_ops, - &sysfs_entry->kobj); - if (!attach_stats_kset) { - ret = -ENOMEM; - goto err_sysfs_attach; - } - - sysfs_entry->attach_stats_kset = attach_stats_kset; - return 0; -err_sysfs_attach: - kobject_del(&sysfs_entry->kobj); err_sysfs_dmabuf: kobject_put(&sysfs_entry->kobj); dmabuf->sysfs_entry = NULL; diff --git a/drivers/dma-buf/dma-buf-sysfs-stats.h b/drivers/dma-buf/dma-buf-sysfs-stats.h index 5f4703249117..a49c6e2650cc 100644 --- a/drivers/dma-buf/dma-buf-sysfs-stats.h +++ b/drivers/dma-buf/dma-buf-sysfs-stats.h @@ -14,23 +14,8 @@ int dma_buf_init_sysfs_statistics(void); void dma_buf_uninit_sysfs_statistics(void); int dma_buf_stats_setup(struct dma_buf *dmabuf); -int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach, - unsigned int uid); -static inline void dma_buf_update_attachment_map_count(struct dma_buf_attachment *attach, - int delta) -{ - struct dma_buf_attach_sysfs_entry *entry = attach->sysfs_entry; - entry->map_counter += delta; -} void dma_buf_stats_teardown(struct dma_buf *dmabuf); -void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach); -static inline unsigned int dma_buf_update_attach_uid(struct dma_buf *dmabuf) -{ - struct dma_buf_sysfs_entry *entry = dmabuf->sysfs_entry; - - return entry->attachment_uid++; -} #else static inline int dma_buf_init_sysfs_statistics(void) @@ -44,19 +29,7 @@ static inline int dma_buf_stats_setup(struct dma_buf *dmabuf) { return 0; } -static inline int dma_buf_attach_stats_setup(struct dma_buf_attachment *attach, - unsigned int uid) -{ - return 0; -} static inline void dma_buf_stats_teardown(struct dma_buf *dmabuf) {} -static inline void dma_buf_attach_stats_teardown(struct dma_buf_attachment *attach) {} -static inline void dma_buf_update_attachment_map_count(struct dma_buf_attachment *attach, - int delta) {} -static inline unsigned int dma_buf_update_attach_uid(struct dma_buf *dmabuf) -{ - return 0; -} #endif #endif // _DMA_BUF_SYSFS_STATS_H diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 510b42771974..b1a6db71c656 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -738,7 +738,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, { struct dma_buf_attachment *attach; int ret; - unsigned int attach_uid; if (WARN_ON(!dmabuf || !dev)) return ERR_PTR(-EINVAL); @@ -764,13 +763,8 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, } dma_resv_lock(dmabuf->resv, NULL); list_add(&attach->node, &dmabuf->attachments); - attach_uid = dma_buf_update_attach_uid(dmabuf); dma_resv_unlock(dmabuf->resv); - ret = dma_buf_attach_stats_setup(attach, attach_uid); - if (ret) - goto err_sysfs; - /* When either the importer or the exporter can't handle dynamic * mappings we cache the mapping here to avoid issues with the * reservation object lock. @@ -797,7 +791,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, dma_resv_unlock(attach->dmabuf->resv); attach->sgt = sgt; attach->dir = DMA_BIDIRECTIONAL; - dma_buf_update_attachment_map_count(attach, 1 /* delta */); } return attach; @@ -814,7 +807,6 @@ err_unlock: if (dma_buf_is_dynamic(attach->dmabuf)) dma_resv_unlock(attach->dmabuf->resv); -err_sysfs: dma_buf_detach(dmabuf, attach); return ERR_PTR(ret); } @@ -864,7 +856,6 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) dma_resv_lock(attach->dmabuf->resv, NULL); __unmap_dma_buf(attach, attach->sgt, attach->dir); - dma_buf_update_attachment_map_count(attach, -1 /* delta */); if (dma_buf_is_dynamic(attach->dmabuf)) { dmabuf->ops->unpin(attach); @@ -878,7 +869,6 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) if (dmabuf->ops->detach) dmabuf->ops->detach(dmabuf, attach); - dma_buf_attach_stats_teardown(attach); kfree(attach); } EXPORT_SYMBOL_GPL(dma_buf_detach); @@ -1020,10 +1010,6 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, } } #endif /* CONFIG_DMA_API_DEBUG */ - - if (!IS_ERR(sg_table)) - dma_buf_update_attachment_map_count(attach, 1 /* delta */); - return sg_table; } EXPORT_SYMBOL_GPL(dma_buf_map_attachment); @@ -1061,8 +1047,6 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, if (dma_buf_is_dynamic(attach->dmabuf) && !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) dma_buf_unpin(attach); - - dma_buf_update_attachment_map_count(attach, -1 /* delta */); } EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 2b814fde0d11..678b2006be78 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -444,15 +444,6 @@ struct dma_buf { struct dma_buf_sysfs_entry { struct kobject kobj; struct dma_buf *dmabuf; - - /** - * @sysfs_entry.attachment_uid: - * - * This is protected by the dma_resv_lock() on @resv and is - * incremented on each attach. - */ - unsigned int attachment_uid; - struct kset *attach_stats_kset; } *sysfs_entry; #endif }; @@ -504,7 +495,6 @@ struct dma_buf_attach_ops { * @importer_ops: importer operations for this attachment, if provided * dma_buf_map/unmap_attachment() must be called with the dma_resv lock held. * @importer_priv: importer specific attachment data. - * @sysfs_entry: For exposing information about this attachment in sysfs. * * This structure holds the attachment information between the dma_buf buffer * and its user device(s). The list contains one attachment struct per device @@ -525,13 +515,6 @@ struct dma_buf_attachment { const struct dma_buf_attach_ops *importer_ops; void *importer_priv; void *priv; -#ifdef CONFIG_DMABUF_SYSFS_STATS - /* for sysfs stats */ - struct dma_buf_attach_sysfs_entry { - struct kobject kobj; - unsigned int map_counter; - } *sysfs_entry; -#endif }; /** -- cgit v1.2.3 From 77e21b50acab326173716830ef15a2f237f2d198 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 16 Jul 2021 08:16:28 +0200 Subject: vgaarb: remove VGA_DEFAULT_DEVICE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The define is entirely unused. Signed-off-by: Christoph Hellwig Link: https://patchwork.freedesktop.org/patch/msgid/20210716061634.2446357-2-hch@lst.de Acked-by: Christian König Signed-off-by: Christian König --- include/linux/vgaarb.h | 6 ------ 1 file changed, 6 deletions(-) (limited to 'include/linux') diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h index dc6ddce92066..26ec8a057d2a 100644 --- a/include/linux/vgaarb.h +++ b/include/linux/vgaarb.h @@ -42,12 +42,6 @@ #define VGA_RSRC_NORMAL_IO 0x04 #define VGA_RSRC_NORMAL_MEM 0x08 -/* Passing that instead of a pci_dev to use the system "default" - * device, that is the one used by vgacon. Archs will probably - * have to provide their own vga_default_device(); - */ -#define VGA_DEFAULT_DEVICE (NULL) - struct pci_dev; /* For use by clients */ -- cgit v1.2.3 From b0b514abc4cf2841ee1e0833252b2e8a78401276 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 16 Jul 2021 08:16:29 +0200 Subject: vgaarb: remove vga_conflicts MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit vga_conflicts only has a single caller and none of the arch overrides mentioned in the comment. Just remove it and the thus dead check in the caller. Signed-off-by: Christoph Hellwig Link: https://patchwork.freedesktop.org/patch/msgid/20210716061634.2446357-3-hch@lst.de Acked-by: Christian König Signed-off-by: Christian König --- drivers/gpu/vga/vgaarb.c | 6 ------ include/linux/vgaarb.h | 12 ------------ 2 files changed, 18 deletions(-) (limited to 'include/linux') diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c index 949fde433ea2..fccc7ef5153a 100644 --- a/drivers/gpu/vga/vgaarb.c +++ b/drivers/gpu/vga/vgaarb.c @@ -284,12 +284,6 @@ static struct vga_device *__vga_tryget(struct vga_device *vgadev, if (vgadev == conflict) continue; - /* Check if the architecture allows a conflict between those - * 2 devices or if they are on separate domains - */ - if (!vga_conflicts(vgadev->pdev, conflict->pdev)) - continue; - /* We have a possible conflict. before we go further, we must * check if we sit on the same bus as the conflicting device. * if we don't, then we must tie both IO and MEM resources diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h index 26ec8a057d2a..ca5160218538 100644 --- a/include/linux/vgaarb.h +++ b/include/linux/vgaarb.h @@ -122,18 +122,6 @@ static inline void vga_set_default_device(struct pci_dev *pdev) { } static inline int vga_remove_vgacon(struct pci_dev *pdev) { return 0; } #endif -/* - * Architectures should define this if they have several - * independent PCI domains that can afford concurrent VGA - * decoding - */ -#ifndef __ARCH_HAS_VGA_CONFLICT -static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2) -{ - return 1; -} -#endif - #if defined(CONFIG_VGA_ARB) int vga_client_register(struct pci_dev *pdev, void *cookie, void (*irq_set_state)(void *cookie, bool state), -- cgit v1.2.3 From 45549c00d3ff05735e7ceb89b20e302301cd6b14 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 16 Jul 2021 08:16:30 +0200 Subject: vgaarb: move the kerneldoc for vga_set_legacy_decoding to vgaarb.c MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Kerneldoc comments should be at the implementation side, not in the header just declaring the prototype. Signed-off-by: Christoph Hellwig Link: https://patchwork.freedesktop.org/patch/msgid/20210716061634.2446357-4-hch@lst.de Acked-by: Christian König Signed-off-by: Christian König --- drivers/gpu/vga/vgaarb.c | 11 +++++++++++ include/linux/vgaarb.h | 13 ------------- 2 files changed, 11 insertions(+), 13 deletions(-) (limited to 'include/linux') diff --git a/drivers/gpu/vga/vgaarb.c b/drivers/gpu/vga/vgaarb.c index fccc7ef5153a..3ed3734f66d9 100644 --- a/drivers/gpu/vga/vgaarb.c +++ b/drivers/gpu/vga/vgaarb.c @@ -834,6 +834,17 @@ bail: spin_unlock_irqrestore(&vga_lock, flags); } +/** + * vga_set_legacy_decoding + * @pdev: pci device of the VGA card + * @decodes: bit mask of what legacy regions the card decodes + * + * Indicates to the arbiter if the card decodes legacy VGA IOs, legacy VGA + * Memory, both, or none. All cards default to both, the card driver (fbdev for + * example) should tell the arbiter if it has disabled legacy decoding, so the + * card can be left out of the arbitration process (and can be safe to take + * interrupts at any time. + */ void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes) { __vga_set_legacy_decoding(pdev, decodes, false); diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h index ca5160218538..fdce9007d57e 100644 --- a/include/linux/vgaarb.h +++ b/include/linux/vgaarb.h @@ -46,19 +46,6 @@ struct pci_dev; /* For use by clients */ -/** - * vga_set_legacy_decoding - * - * @pdev: pci device of the VGA card - * @decodes: bit mask of what legacy regions the card decodes - * - * Indicates to the arbiter if the card decodes legacy VGA IOs, - * legacy VGA Memory, both, or none. All cards default to both, - * the card driver (fbdev for example) should tell the arbiter - * if it has disabled legacy decoding, so the card can be left - * out of the arbitration process (and can be safe to take - * interrupts at any time. - */ #if defined(CONFIG_VGA_ARB) extern void vga_set_legacy_decoding(struct pci_dev *pdev, unsigned int decodes); -- cgit v1.2.3 From 6609176f56ad895ba25d4c120c707fb15f45aa4e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 16 Jul 2021 08:16:31 +0200 Subject: vgaarb: cleanup vgaarb.h MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Merge the different CONFIG_VGA_ARB ifdef blocks, remove superflous externs, and regularize the stubs for !CONFIG_VGA_ARB. Signed-off-by: Christoph Hellwig Link: https://patchwork.freedesktop.org/patch/msgid/20210716061634.2446357-5-hch@lst.de Acked-by: Christian König Signed-off-by: Christian König --- include/linux/vgaarb.h | 90 +++++++++++++++++++++++--------------------------- 1 file changed, 42 insertions(+), 48 deletions(-) (limited to 'include/linux') diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h index fdce9007d57e..05171fc7e26a 100644 --- a/include/linux/vgaarb.h +++ b/include/linux/vgaarb.h @@ -33,6 +33,8 @@ #include