diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2022-09-08 16:56:52 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-09-21 13:14:46 -0600 |
| commit | 76de6749d1bc1817367fedda94cd7c5d325df6c4 (patch) | |
| tree | f51fef426073ca174c3e6baab5bb0e400eb6a0ae /io_uring | |
| parent | ac9e5784bbe72f4f603d1af84760ec09bc0b5ccd (diff) | |
io_uring: further limit non-owner defer-tw cq waiting
In case of DEFER_TASK_WORK we try to restrict waiters to only one task,
which is also the only submitter; however, we don't do it reliably,
which might be very confusing and backfire in the future. E.g. we
currently allow multiple tasks in io_iopoll_check().
Fixes: c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/94c83c0a7fe468260ee2ec31bdb0095d6e874ba2.1662652536.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 6 | ||||
| -rw-r--r-- | io_uring/io_uring.h | 11 |
2 files changed, 17 insertions, 0 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index b5245c5d102c..e95877398b57 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1398,6 +1398,9 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min) int ret = 0; unsigned long check_cq; + if (!io_allowed_run_tw(ctx)) + return -EEXIST; + check_cq = READ_ONCE(ctx->check_cq); if (unlikely(check_cq)) { if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)) @@ -2382,6 +2385,9 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, ktime_t timeout = KTIME_MAX; int ret; + if (!io_allowed_run_tw(ctx)) + return -EEXIST; + do { /* always run at least 1 task work to process local work */ ret = io_run_task_work_ctx(ctx); diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index 9d89425292b7..4eea0836170e 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -329,4 +329,15 @@ static inline struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx) return container_of(node, struct io_kiocb, comp_list); } +static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx) +{ + if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) + return true; + if (unlikely(ctx->submitter_task != current)) { + /* maybe this is before any submissions */ + return !ctx->submitter_task; + } + return true; +} + #endif |