6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavel Begunkov <asml.silence@xxxxxxxxx> Commit 8d09a88ef9d3cb7d21d45c39b7b7c31298d23998 upstream. Conditional locking is never great, in case of __io_cqring_overflow_flush(), which is a slow path, it's not justified. Don't handle IOPOLL separately, always grab uring_lock for overflow flushing. Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> Link: https://lore.kernel.org/r/162947df299aa12693ac4b305dacedab32ec7976.1712708261.git.asml.silence@xxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- io_uring/io_uring.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -593,6 +593,8 @@ static bool __io_cqring_overflow_flush(s bool all_flushed; size_t cqe_size = sizeof(struct io_uring_cqe); + lockdep_assert_held(&ctx->uring_lock); + if (!force && __io_cqring_events(ctx) == ctx->cq_entries) return false; @@ -647,12 +649,9 @@ static bool io_cqring_overflow_flush(str bool ret = true; if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) { - /* iopoll syncs against uring_lock, not completion_lock */ - if (ctx->flags & IORING_SETUP_IOPOLL) - mutex_lock(&ctx->uring_lock); + mutex_lock(&ctx->uring_lock); ret = __io_cqring_overflow_flush(ctx, false); - if (ctx->flags & IORING_SETUP_IOPOLL) - mutex_unlock(&ctx->uring_lock); + mutex_unlock(&ctx->uring_lock); } return ret; @@ -1405,6 +1404,8 @@ static int io_iopoll_check(struct io_rin int ret = 0; unsigned long check_cq; + lockdep_assert_held(&ctx->uring_lock); + if (!io_allowed_run_tw(ctx)) return -EEXIST;
