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linux/io_uring/tw.c

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io_uring: split out task work code into tw.c Move the task work handling code out of io_uring.c into a new tw.c file. This includes the local work, normal work, and fallback work handling infrastructure. The associated tw.h header contains io_should_terminate_tw() as a static inline helper, along with the necessary function declarations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:55:45 -07:00
io_uring: split out CQ waiting code into wait.c Move the completion queue waiting and scheduling code out of io_uring.c into a dedicated wait.c file. This further removes code out of the main io_uring C and header file, and into a topical new file. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:40:19 -07:00
io_uring: split out task work code into tw.c Move the task work handling code out of io_uring.c into a new tw.c file. This includes the local work, normal work, and fallback work handling infrastructure. The associated tw.h header contains io_should_terminate_tw() as a static inline helper, along with the necessary function declarations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:55:45 -07:00
io_uring: ensure ctx->rings is stable for task work flags manipulation If DEFER_TASKRUN | SETUP_TASKRUN is used and task work is added while the ring is being resized, it's possible for the OR'ing of IORING_SQ_TASKRUN to happen in the small window of swapping into the new rings and the old rings being freed. Prevent this by adding a 2nd ->rings pointer, ->rings_rcu, which is protected by RCU. The task work flags manipulation is inside RCU already, and if the resize ring freeing is done post an RCU synchronize, then there's no need to add locking to the fast path of task work additions. Note: this is only done for DEFER_TASKRUN, as that's the only setup mode that supports ring resizing. If this ever changes, then they too need to use the io_ctx_mark_taskrun() helper. Link: https://lore.kernel.org/io-uring/20260309062759.482210-1-naup96721@gmail.com/ Cc: stable@vger.kernel.org Fixes: 79cfe9e59c2a ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS") Reported-by: Hao-Yu Yang <naup96721@gmail.com> Suggested-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 14:21:37 -06:00
io_uring: split out task work code into tw.c Move the task work handling code out of io_uring.c into a new tw.c file. This includes the local work, normal work, and fallback work handling infrastructure. The associated tw.h header contains io_should_terminate_tw() as a static inline helper, along with the necessary function declarations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:55:45 -07:00
io_uring: ensure ctx->rings is stable for task work flags manipulation If DEFER_TASKRUN | SETUP_TASKRUN is used and task work is added while the ring is being resized, it's possible for the OR'ing of IORING_SQ_TASKRUN to happen in the small window of swapping into the new rings and the old rings being freed. Prevent this by adding a 2nd ->rings pointer, ->rings_rcu, which is protected by RCU. The task work flags manipulation is inside RCU already, and if the resize ring freeing is done post an RCU synchronize, then there's no need to add locking to the fast path of task work additions. Note: this is only done for DEFER_TASKRUN, as that's the only setup mode that supports ring resizing. If this ever changes, then they too need to use the io_ctx_mark_taskrun() helper. Link: https://lore.kernel.org/io-uring/20260309062759.482210-1-naup96721@gmail.com/ Cc: stable@vger.kernel.org Fixes: 79cfe9e59c2a ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS") Reported-by: Hao-Yu Yang <naup96721@gmail.com> Suggested-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 14:21:37 -06:00
io_uring: mark known and harmless racy ctx->int_flags uses There are a few of these, where flags are read outside of the uring_lock, yet it's harmless to race on them. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-14 08:46:17 -06:00
io_uring: split out task work code into tw.c Move the task work handling code out of io_uring.c into a new tw.c file. This includes the local work, normal work, and fallback work handling infrastructure. The associated tw.h header contains io_should_terminate_tw() as a static inline helper, along with the necessary function declarations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:55:45 -07:00
io_uring: ensure ctx->rings is stable for task work flags manipulation If DEFER_TASKRUN | SETUP_TASKRUN is used and task work is added while the ring is being resized, it's possible for the OR'ing of IORING_SQ_TASKRUN to happen in the small window of swapping into the new rings and the old rings being freed. Prevent this by adding a 2nd ->rings pointer, ->rings_rcu, which is protected by RCU. The task work flags manipulation is inside RCU already, and if the resize ring freeing is done post an RCU synchronize, then there's no need to add locking to the fast path of task work additions. Note: this is only done for DEFER_TASKRUN, as that's the only setup mode that supports ring resizing. If this ever changes, then they too need to use the io_ctx_mark_taskrun() helper. Link: https://lore.kernel.org/io-uring/20260309062759.482210-1-naup96721@gmail.com/ Cc: stable@vger.kernel.org Fixes: 79cfe9e59c2a ("io_uring/register: add IORING_REGISTER_RESIZE_RINGS") Reported-by: Hao-Yu Yang <naup96721@gmail.com> Suggested-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09 14:21:37 -06:00
io_uring: split out task work code into tw.c Move the task work handling code out of io_uring.c into a new tw.c file. This includes the local work, normal work, and fallback work handling infrastructure. The associated tw.h header contains io_should_terminate_tw() as a static inline helper, along with the necessary function declarations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:55:45 -07:00
io_uring/tw: serialize ctx->retry_llist with ->uring_lock The DEFER_TASKRUN local task work paths all run under ctx->uring_lock, which serializes them with each other and with the rest of the ring's hot paths. io_move_task_work_from_local() is the exception - it's called from io_ring_exit_work() on a kworker without holding the lock and from the iopoll cancelation side right after dropping it. ->work_llist is fine with this, as it's only ever updated via the expected paths. But the ->retry_llist is updated while runing, and hence it could potentially race between normal task_work running and the task-has-exited shutdown path. Simply grab ->uring_lock while moving the local work to the fallback list for exit purposes, which nicely serializes it across both the normal additions and the exit prune path. Cc: stable@vger.kernel.org Fixes: f46b9cdb22f7 ("io_uring: limit local tw done") Reported-by: Robert Femmer <robert.femmer@x41-dsec.de> Reported-by: Christian Reitter <invd@inhq.net> Reported-by: Michael Rodler <michael.rodler@x41-dsec.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-27 14:29:02 -06:00
io_uring: split out task work code into tw.c Move the task work handling code out of io_uring.c into a new tw.c file. This includes the local work, normal work, and fallback work handling infrastructure. The associated tw.h header contains io_should_terminate_tw() as a static inline helper, along with the necessary function declarations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:55:45 -07:00
io_uring/tw: serialize ctx->retry_llist with ->uring_lock The DEFER_TASKRUN local task work paths all run under ctx->uring_lock, which serializes them with each other and with the rest of the ring's hot paths. io_move_task_work_from_local() is the exception - it's called from io_ring_exit_work() on a kworker without holding the lock and from the iopoll cancelation side right after dropping it. ->work_llist is fine with this, as it's only ever updated via the expected paths. But the ->retry_llist is updated while runing, and hence it could potentially race between normal task_work running and the task-has-exited shutdown path. Simply grab ->uring_lock while moving the local work to the fallback list for exit purposes, which nicely serializes it across both the normal additions and the exit prune path. Cc: stable@vger.kernel.org Fixes: f46b9cdb22f7 ("io_uring: limit local tw done") Reported-by: Robert Femmer <robert.femmer@x41-dsec.de> Reported-by: Christian Reitter <invd@inhq.net> Reported-by: Michael Rodler <michael.rodler@x41-dsec.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-27 14:29:02 -06:00
io_uring: split out task work code into tw.c Move the task work handling code out of io_uring.c into a new tw.c file. This includes the local work, normal work, and fallback work handling infrastructure. The associated tw.h header contains io_should_terminate_tw() as a static inline helper, along with the necessary function declarations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 08:55:45 -07:00