6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jens Axboe axboe@kernel.dk
commit 73eaa2b583493b680c6f426531d6736c39643bfb upstream.
Rather than use the system unbound event workqueue, use an io_uring specific one. This avoids dependencies with the tty, which also uses the system_unbound_wq, and issues flushes of said workqueue from inside its poll handling.
Cc: stable@vger.kernel.org Reported-by: Rasmus Karlsson rasmus.karlsson@pajlada.com Tested-by: Rasmus Karlsson rasmus.karlsson@pajlada.com Tested-by: Iskren Chernev me@iskren.info Link: https://github.com/axboe/liburing/issues/1113 Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- io_uring/io_uring.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -148,6 +148,7 @@ static bool io_uring_try_cancel_requests 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; @@ -3180,7 +3181,7 @@ static __cold void io_ring_ctx_wait_and_ * 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) @@ -4664,6 +4665,8 @@ static int __init io_uring_init(void) offsetof(struct io_kiocb, cmd.data), sizeof_field(struct io_kiocb, cmd.data), NULL);
+ iou_wq = alloc_workqueue("iou_exit", WQ_UNBOUND, 64); + #ifdef CONFIG_SYSCTL register_sysctl_init("kernel", kernel_io_uring_disabled_table); #endif