kernel/linux.git/drivers/char/virtio_console.c, branch v5.9.12

virtio: virtio_console: fix DMA memory allocation for rproc serial

2020-11-18T18:22:26+00:00

commit 9d516aa82b7d4fbe7f6303348697960ba03a530b upstream. Since commit 086d08725d34 ("remoteproc: create vdev subdevice with specific dma memory pool"), every remoteproc has a DMA subdevice ("remoteprocX#vdevYbuffer") for each virtio device, which inherits DMA capabilities from the corresponding platform device. This allowed to associate different DMA pools with each vdev, and required from virtio drivers to perform DMA operations with the parent device (vdev->dev.parent) instead of grandparent (vdev->dev.parent->parent). virtio_rpmsg_bus was already changed in the same merge cycle with commit d999b622fcfb ("rpmsg: virtio: allocate buffer from parent"), but virtio_console did not. In fact, operations using the grandparent worked fine while the grandparent was the platform device, but since commit c774ad010873 ("remoteproc: Fix and restore the parenting hierarchy for vdev") this was changed, and now the grandparent device is the remoteproc device without any DMA capabilities. So, starting v5.8-rc1 the following warning is observed: [ 2.483925] ------------[ cut here ]------------ [ 2.489148] WARNING: CPU: 3 PID: 101 at kernel/dma/mapping.c:427 0x80e7eee8 [ 2.489152] Modules linked in: virtio_console(+) [ 2.503737] virtio_rpmsg_bus rpmsg_core [ 2.508903] [ 2.528898] [ 2.913043] [ 2.914907] ---[ end trace 93ac8746beab612c ]--- [ 2.920102] virtio-ports vport1p0: Error allocating inbufs kernel/dma/mapping.c:427 is: WARN_ON_ONCE(!dev->coherent_dma_mask); obviously because the grandparent now is remoteproc dev without any DMA caps: [ 3.104943] Parent: remoteproc0#vdev1buffer, grandparent: remoteproc0 Fix this the same way as it was for virtio_rpmsg_bus, using just the parent device (vdev->dev.parent, "remoteprocX#vdevYbuffer") for DMA operations. This also allows now to reserve DMA pools/buffers for rproc serial via Device Tree. Fixes: c774ad010873 ("remoteproc: Fix and restore the parenting hierarchy for vdev") Cc: stable@vger.kernel.org # 5.1+ Reviewed-by: Mathieu Poirier Acked-by: Jason Wang Signed-off-by: Alexander Lobakin Date: Thu, 5 Nov 2020 11:10:24 +0800 Link: https://lore.kernel.org/r/AOKowLclCbOCKxyiJ71WeNyuAAj2q8EUtxrXbyky5E@cp7-web-042.plabs.ch Signed-off-by: Greg Kroah-Hartman

Merge v5.8-rc6 into char-misc-next

2020-07-20T07:43:40+00:00

We need the char/misc fixes in here as well. Signed-off-by: Greg Kroah-Hartman

virtio: virtio_console: add missing MODULE_DEVICE_TABLE() for rproc serial

2020-07-10T13:12:48+00:00

rproc_serial_id_table lacks an exposure to module devicetable, so when remoteproc firmware requests VIRTIO_ID_RPROC_SERIAL, no uevent is generated and no module autoloading occurs. Add missing MODULE_DEVICE_TABLE() annotation and move the existing one for VIRTIO_ID_CONSOLE right to the table itself. Fixes: 1b6370463e88 ("virtio_console: Add support for remoteproc serial") Cc: # v3.8+ Signed-off-by: Alexander Lobakin Reviewed-by: Amit Shah Link: https://lore.kernel.org/r/x7C_CbeJtoGMy258nwAXASYz3xgFMFpyzmUvOyZzRnQrgWCREBjaqBOpAUS7ol4NnZYvSVwmTsCG0Ohyfvta-ygw6HMHcoeKK0C3QFiAO_Q=@pm.me Signed-off-by: Greg Kroah-Hartman

virtio_console: Constify some static variables

2020-07-10T12:50:51+00:00

The id_table and feature_table pointers in struct virtio_driver are pointers to const. Mark the corresponding static variables const to allow the compiler to put them in read-only memory. Before: text data bss dec hex filename 25447 713 76 26236 667c drivers/char/virtio_console.o After: text data bss dec hex filename 25488 673 76 26237 667d drivers/char/virtio_console.o Signed-off-by: Rikard Falkeborn Acked-by: Arnd Bergmann Reviewed-by: Amit Shah Link: https://lore.kernel.org/r/20200701200950.30314-6-rikard.falkeborn@gmail.com Signed-off-by: Greg Kroah-Hartman

fs: rename pipe_buf ->steal to ->try_steal

2020-05-20T16:14:10+00:00

And replace the arcane return value convention with a simple bool where true means success and false means failure. [AV: braino fix folded in] Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

char: virtio: Replace zero-length array with flexible-array member

2020-02-14T17:16:01+00:00

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertenly introduced[3] to the codebase from now on. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Link: https://lore.kernel.org/r/20200211222941.GA7657@embeddedor Signed-off-by: Greg Kroah-Hartman

Merge tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

2019-11-30T22:12:13+00:00

Pull pipe rework from David Howells: "This is my set of preparatory patches for building a general notification queue on top of pipes. It makes a number of significant changes: - It removes the nr_exclusive argument from __wake_up_sync_key() as this is always 1. This prepares for the next step: - Adds wake_up_interruptible_sync_poll_locked() so that poll can be woken up from a function that's holding the poll waitqueue spinlock. - Change the pipe buffer ring to be managed in terms of unbounded head and tail indices rather than bounded index and length. This means that reading the pipe only needs to modify one index, not two. - A selection of helper functions are provided to query the state of the pipe buffer, plus a couple to apply updates to the pipe indices. - The pipe ring is allowed to have kernel-reserved slots. This allows many notification messages to be spliced in by the kernel without allowing userspace to pin too many pages if it writes to the same pipe. - Advance the head and tail indices inside the pipe waitqueue lock and use wake_up_interruptible_sync_poll_locked() to poke poll without having to take the lock twice. - Rearrange pipe_write() to preallocate the buffer it is going to write into and then drop the spinlock. This allows kernel notifications to then be added the ring whilst it is filling the buffer it allocated. The read side is stalled because the pipe mutex is still held. - Don't wake up readers on a pipe if there was already data in it when we added more. - Don't wake up writers on a pipe if the ring wasn't full before we removed a buffer" * tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: pipe: Remove sync on wake_ups pipe: Increase the writer-wakeup threshold to reduce context-switch count pipe: Check for ring full inside of the spinlock in pipe_write() pipe: Remove redundant wakeup from pipe_write() pipe: Rearrange sequence in pipe_write() to preallocate slot pipe: Conditionalise wakeup in pipe_read() pipe: Advance tail pointer inside of wait spinlock in pipe_read() pipe: Allow pipes to have kernel-reserved slots pipe: Use head and tail pointers for the ring, not cursor and length Add wake_up_interruptible_sync_poll_locked() Remove the nr_exclusive argument from __wake_up_sync_key() pipe: Reduce #inclusion of pipe_fs_i.h

virtio_console: allocate inbufs in add_port() only if it is needed

2019-11-19T10:13:49+00:00

When we hot unplug a virtserialport and then try to hot plug again, it fails: (qemu) chardev-add socket,id=serial0,path=/tmp/serial0,server,nowait (qemu) device_add virtserialport,bus=virtio-serial0.0,nr=2,\ chardev=serial0,id=serial0,name=serial0 (qemu) device_del serial0 (qemu) device_add virtserialport,bus=virtio-serial0.0,nr=2,\ chardev=serial0,id=serial0,name=serial0 kernel error: virtio-ports vport2p2: Error allocating inbufs qemu error: virtio-serial-bus: Guest failure in adding port 2 for device \ virtio-serial0.0 This happens because buffers for the in_vq are allocated when the port is added but are not released when the port is unplugged. They are only released when virtconsole is removed (see a7a69ec0d8e4) To avoid the problem and to be symmetric, we could allocate all the buffers in init_vqs() as they are released in remove_vqs(), but it sounds like a waste of memory. Rather than that, this patch changes add_port() logic to ignore ENOSPC error in fill_queue(), which means queue has already been filled. Fixes: a7a69ec0d8e4 ("virtio_console: free buffers after reset") Cc: mst@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Laurent Vivier Signed-off-by: Michael S. Tsirkin

pipe: Use head and tail pointers for the ring, not cursor and length

2019-10-31T15:12:34+00:00

Convert pipes to use head and tail pointers for the buffer ring rather than pointer and length as the latter requires two atomic ops to update (or a combined op) whereas the former only requires one. (1) The head pointer is the point at which production occurs and points to the slot in which the next buffer will be placed. This is equivalent to pipe->curbuf + pipe->nrbufs. The head pointer belongs to the write-side. (2) The tail pointer is the point at which consumption occurs. It points to the next slot to be consumed. This is equivalent to pipe->curbuf. The tail pointer belongs to the read-side. (3) head and tail are allowed to run to UINT_MAX and wrap naturally. They are only masked off when the array is being accessed, e.g.: pipe->bufs[head & mask] This means that it is not necessary to have a dead slot in the ring as head == tail isn't ambiguous. (4) The ring is empty if "head == tail". A helper, pipe_empty(), is provided for this. (5) The occupancy of the ring is "head - tail". A helper, pipe_occupancy(), is provided for this. (6) The number of free slots in the ring is "pipe->ring_size - occupancy". A helper, pipe_space_for_user() is provided to indicate how many slots userspace may use. (7) The ring is full if "head - tail >= pipe->ring_size". A helper, pipe_full(), is provided for this. Signed-off-by: David Howells

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman