| Message ID | 94c83c0a7fe468260ee2ec31bdb0095d6e874ba2.1662652536.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | defer tw fixes and other cleanups | expand |
On Thu, 2022-09-08 at 16:56 +0100, Pavel Begunkov wrote: > 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: dacbb30102689 ("io_uring: add IORING_SETUP_DEFER_TASKRUN") > Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> > --- > io_uring/io_uring.c | 6 ++++++ > io_uring/io_uring.h | 11 +++++++++++ > 2 files changed, 17 insertions(+) > > diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c > index 0482087b7c64..dc6f64ecd926 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)) > @@ -2386,6 +2389,9 @@ 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 Reviewed-by: Dylan Yudaken <dylany@fb.com>
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 0482087b7c64..dc6f64ecd926 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)) @@ -2386,6 +2389,9 @@ 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
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: dacbb30102689 ("io_uring: add IORING_SETUP_DEFER_TASKRUN") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- io_uring/io_uring.c | 6 ++++++ io_uring/io_uring.h | 11 +++++++++++ 2 files changed, 17 insertions(+)