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 --- 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 3974b4f124b6..5ba312ab9978 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)