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-rw-r--r--io_uring/io_uring.c31
-rw-r--r--io_uring/kbuf.c118
-rw-r--r--io_uring/kbuf.h8
-rw-r--r--io_uring/rw.c9
4 files changed, 73 insertions, 93 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 5d4b448fdc50..4521c2b66b98 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -147,6 +147,7 @@ static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
static void io_queue_sqe(struct io_kiocb *req);
struct kmem_cache *req_cachep;
+static struct workqueue_struct *iou_wq __ro_after_init;
static int __read_mostly sysctl_io_uring_disabled;
static int __read_mostly sysctl_io_uring_group = -1;
@@ -350,7 +351,6 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
err:
kfree(ctx->cancel_table.hbs);
kfree(ctx->cancel_table_locked.hbs);
- kfree(ctx->io_bl);
xa_destroy(&ctx->io_bl_xa);
kfree(ctx);
return NULL;
@@ -1982,10 +1982,15 @@ fail:
err = -EBADFD;
if (!io_file_can_poll(req))
goto fail;
- err = -ECANCELED;
- if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
- goto fail;
- return;
+ if (req->file->f_flags & O_NONBLOCK ||
+ req->file->f_mode & FMODE_NOWAIT) {
+ err = -ECANCELED;
+ if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
+ goto fail;
+ return;
+ } else {
+ req->flags &= ~REQ_F_APOLL_MULTISHOT;
+ }
}
if (req->flags & REQ_F_FORCE_ASYNC) {
@@ -2926,7 +2931,6 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
io_napi_free(ctx);
kfree(ctx->cancel_table.hbs);
kfree(ctx->cancel_table_locked.hbs);
- kfree(ctx->io_bl);
xa_destroy(&ctx->io_bl_xa);
kfree(ctx);
}
@@ -3161,7 +3165,7 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
* noise and overhead, there's no discernable change in runtime
* over using system_wq.
*/
- queue_work(system_unbound_wq, &ctx->exit_work);
+ queue_work(iou_wq, &ctx->exit_work);
}
static int io_uring_release(struct inode *inode, struct file *file)
@@ -3443,14 +3447,15 @@ static void *io_uring_validate_mmap_request(struct file *file,
ptr = ctx->sq_sqes;
break;
case IORING_OFF_PBUF_RING: {
+ struct io_buffer_list *bl;
unsigned int bgid;
bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
- rcu_read_lock();
- ptr = io_pbuf_get_address(ctx, bgid);
- rcu_read_unlock();
- if (!ptr)
- return ERR_PTR(-EINVAL);
+ bl = io_pbuf_get_bl(ctx, bgid);
+ if (IS_ERR(bl))
+ return bl;
+ ptr = bl->buf_ring;
+ io_put_bl(ctx, bl);
break;
}
default:
@@ -4185,6 +4190,8 @@ static int __init io_uring_init(void)
io_buf_cachep = KMEM_CACHE(io_buffer,
SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);
+ iou_wq = alloc_workqueue("iou_exit", WQ_UNBOUND, 64);
+
#ifdef CONFIG_SYSCTL
register_sysctl_init("kernel", kernel_io_uring_disabled_table);
#endif
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 693c26da4ee1..3aa16e27f509 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -17,8 +17,6 @@
#define IO_BUFFER_LIST_BUF_PER_PAGE (PAGE_SIZE / sizeof(struct io_uring_buf))
-#define BGID_ARRAY 64
-
/* BIDs are addressed by a 16-bit field in a CQE */
#define MAX_BIDS_PER_BGID (1 << 16)
@@ -40,13 +38,9 @@ struct io_buf_free {
int inuse;
};
-static struct io_buffer_list *__io_buffer_get_list(struct io_ring_ctx *ctx,
- struct io_buffer_list *bl,
- unsigned int bgid)
+static inline struct io_buffer_list *__io_buffer_get_list(struct io_ring_ctx *ctx,
+ unsigned int bgid)
{
- if (bl && bgid < BGID_ARRAY)
- return &bl[bgid];
-
return xa_load(&ctx->io_bl_xa, bgid);
}
@@ -55,7 +49,7 @@ static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx,
{
lockdep_assert_held(&ctx->uring_lock);
- return __io_buffer_get_list(ctx, ctx->io_bl, bgid);
+ return __io_buffer_get_list(ctx, bgid);
}
static int io_buffer_add_list(struct io_ring_ctx *ctx,
@@ -67,11 +61,7 @@ static int io_buffer_add_list(struct io_ring_ctx *ctx,
* always under the ->uring_lock, but the RCU lookup from mmap does.
*/
bl->bgid = bgid;
- smp_store_release(&bl->is_ready, 1);
-
- if (bgid < BGID_ARRAY)
- return 0;
-
+ atomic_set(&bl->refs, 1);
return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL));
}
@@ -208,24 +198,6 @@ void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
return ret;
}
-static __cold int io_init_bl_list(struct io_ring_ctx *ctx)
-{
- struct io_buffer_list *bl;
- int i;
-
- bl = kcalloc(BGID_ARRAY, sizeof(struct io_buffer_list), GFP_KERNEL);
- if (!bl)
- return -ENOMEM;
-
- for (i = 0; i < BGID_ARRAY; i++) {
- INIT_LIST_HEAD(&bl[i].buf_list);
- bl[i].bgid = i;
- }
-
- smp_store_release(&ctx->io_bl, bl);
- return 0;
-}
-
/*
* Mark the given mapped range as free for reuse
*/
@@ -294,24 +266,24 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx,
return i;
}
+void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl)
+{
+ if (atomic_dec_and_test(&bl->refs)) {
+ __io_remove_buffers(ctx, bl, -1U);
+ kfree_rcu(bl, rcu);
+ }
+}
+
void io_destroy_buffers(struct io_ring_ctx *ctx)
{
struct io_buffer_list *bl;
struct list_head *item, *tmp;
struct io_buffer *buf;
unsigned long index;
- int i;
-
- for (i = 0; i < BGID_ARRAY; i++) {
- if (!ctx->io_bl)
- break;
- __io_remove_buffers(ctx, &ctx->io_bl[i], -1U);
- }
xa_for_each(&ctx->io_bl_xa, index, bl) {
xa_erase(&ctx->io_bl_xa, bl->bgid);
- __io_remove_buffers(ctx, bl, -1U);
- kfree_rcu(bl, rcu);
+ io_put_bl(ctx, bl);
}
/*
@@ -489,12 +461,6 @@ int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
io_ring_submit_lock(ctx, issue_flags);
- if (unlikely(p->bgid < BGID_ARRAY && !ctx->io_bl)) {
- ret = io_init_bl_list(ctx);
- if (ret)
- goto err;
- }
-
bl = io_buffer_get_list(ctx, p->bgid);
if (unlikely(!bl)) {
bl = kzalloc(sizeof(*bl), GFP_KERNEL_ACCOUNT);
@@ -507,14 +473,9 @@ int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
if (ret) {
/*
* Doesn't need rcu free as it was never visible, but
- * let's keep it consistent throughout. Also can't
- * be a lower indexed array group, as adding one
- * where lookup failed cannot happen.
+ * let's keep it consistent throughout.
*/
- if (p->bgid >= BGID_ARRAY)
- kfree_rcu(bl, rcu);
- else
- WARN_ON_ONCE(1);
+ kfree_rcu(bl, rcu);
goto err;
}
}
@@ -679,12 +640,6 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
if (reg.ring_entries >= 65536)
return -EINVAL;
- if (unlikely(reg.bgid < BGID_ARRAY && !ctx->io_bl)) {
- int ret = io_init_bl_list(ctx);
- if (ret)
- return ret;
- }
-
bl = io_buffer_get_list(ctx, reg.bgid);
if (bl) {
/* if mapped buffer ring OR classic exists, don't allow */
@@ -733,11 +688,8 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
if (!bl->is_buf_ring)
return -EINVAL;
- __io_remove_buffers(ctx, bl, -1U);
- if (bl->bgid >= BGID_ARRAY) {
- xa_erase(&ctx->io_bl_xa, bl->bgid);
- kfree_rcu(bl, rcu);
- }
+ xa_erase(&ctx->io_bl_xa, bl->bgid);
+ io_put_bl(ctx, bl);
return 0;
}
@@ -767,23 +719,35 @@ int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg)
return 0;
}
-void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
+struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx,
+ unsigned long bgid)
{
struct io_buffer_list *bl;
+ bool ret;
- bl = __io_buffer_get_list(ctx, smp_load_acquire(&ctx->io_bl), bgid);
-
- if (!bl || !bl->is_mmap)
- return NULL;
/*
- * Ensure the list is fully setup. Only strictly needed for RCU lookup
- * via mmap, and in that case only for the array indexed groups. For
- * the xarray lookups, it's either visible and ready, or not at all.
+ * We have to be a bit careful here - we're inside mmap and cannot grab
+ * the uring_lock. This means the buffer_list could be simultaneously
+ * going away, if someone is trying to be sneaky. Look it up under rcu
+ * so we know it's not going away, and attempt to grab a reference to
+ * it. If the ref is already zero, then fail the mapping. If successful,
+ * the caller will call io_put_bl() to drop the the reference at at the
+ * end. This may then safely free the buffer_list (and drop the pages)
+ * at that point, vm_insert_pages() would've already grabbed the
+ * necessary vma references.
*/
- if (!smp_load_acquire(&bl->is_ready))
- return NULL;
-
- return bl->buf_ring;
+ rcu_read_lock();
+ bl = xa_load(&ctx->io_bl_xa, bgid);
+ /* must be a mmap'able buffer ring and have pages */
+ ret = false;
+ if (bl && bl->is_mmap)
+ ret = atomic_inc_not_zero(&bl->refs);
+ rcu_read_unlock();
+
+ if (ret)
+ return bl;
+
+ return ERR_PTR(-EINVAL);
}
/*
diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
index 1c7b654ee726..df365b8860cf 100644
--- a/io_uring/kbuf.h
+++ b/io_uring/kbuf.h
@@ -25,12 +25,12 @@ struct io_buffer_list {
__u16 head;
__u16 mask;
+ atomic_t refs;
+
/* ring mapped provided buffers */
__u8 is_buf_ring;
/* ring mapped provided buffers, but mmap'ed by application */
__u8 is_mmap;
- /* bl is visible from an RCU point of view for lookup */
- __u8 is_ready;
};
struct io_buffer {
@@ -61,7 +61,9 @@ void __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
-void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid);
+void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl);
+struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx,
+ unsigned long bgid);
static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
{
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 0585ebcc9773..c8d48287439e 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -937,6 +937,13 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
ret = __io_read(req, issue_flags);
/*
+ * If the file doesn't support proper NOWAIT, then disable multishot
+ * and stay in single shot mode.
+ */
+ if (!io_file_supports_nowait(req))
+ req->flags &= ~REQ_F_APOLL_MULTISHOT;
+
+ /*
* If we get -EAGAIN, recycle our buffer and just let normal poll
* handling arm it.
*/
@@ -955,7 +962,7 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
/*
* Any successful return value will keep the multishot read armed.
*/
- if (ret > 0) {
+ if (ret > 0 && req->flags & REQ_F_APOLL_MULTISHOT) {
/*
* Put our buffer and post a CQE. If we fail to post a CQE, then
* jump to the termination path. This request is then done.
generated by cgit v1.2.3 (git 2.39.0) at 2025-02-25 19:25:05 +0300