[PATCH 5.10 003/103] io_uring: limit {io|sq}poll submit locking scope
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-01-15 12:48:16
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Pavel Begunkov <asml.silence@gmail.com> commit 89448c47b8452b67c146dc6cad6f737e004c5caf upstream We don't need to take uring_lock for SQPOLL|IOPOLL to do io_cqring_overflow_flush() when cq_overflow_list is empty, remove it from the hot path. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/io_uring.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 3974b4f124b6a..5ba312ab99786 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c@@ -9024,10 +9024,13 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, */ ret = 0; if (ctx->flags & IORING_SETUP_SQPOLL) { - io_ring_submit_lock(ctx, (ctx->flags & IORING_SETUP_IOPOLL)); - if (!list_empty_careful(&ctx->cq_overflow_list)) + if (!list_empty_careful(&ctx->cq_overflow_list)) { + bool needs_lock = ctx->flags & IORING_SETUP_IOPOLL; + + io_ring_submit_lock(ctx, needs_lock); io_cqring_overflow_flush(ctx, false, NULL, NULL); - io_ring_submit_unlock(ctx, (ctx->flags & IORING_SETUP_IOPOLL)); + io_ring_submit_unlock(ctx, needs_lock); + } if (flags & IORING_ENTER_SQ_WAKEUP) wake_up(&ctx->sq_data->wait); if (flags & IORING_ENTER_SQ_WAIT)
--
2.27.0