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linux/io_uring/waitid.c

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io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: add wrapper type for io_req_tw_func_t arg In preparation for uring_cmd implementations to implement functions with the io_req_tw_func_t signature, introduce a wrapper struct io_tw_req to hide the struct io_kiocb * argument. The intention is for only the io_uring core to access the inner struct io_kiocb *. uring_cmd implementations should instead call a helper from io_uring/cmd.h to convert struct io_tw_req to struct io_uring_cmd *. Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-31 14:34:29 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: add async data clear/free helpers Futex recently had an issue where it mishandled how ->async_data and REQ_F_ASYNC_DATA is handled. To avoid future issues like that, add a set of helpers that either clear or clear-and-free the async data assigned to a struct io_kiocb. Convert existing manual handling of that to use the helpers. No intended functional changes in this patch. Reviewed-by: Caleb Sander Mateos <csander@purestorage.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-22 08:19:56 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: use io_is_compat() Use io_is_compat() for consistency. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Link: https://lore.kernel.org/r/28c5b5f1f1bf7f4d18869dafe6e4147ce1bbf0f5.1740400452.git.asml.silence@gmail.com Link: https://lore.kernel.org/r/20250224172337.2009871-1-csander@purestorage.com [axboe: fold in improvement from Caleb, see link] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-24 12:42:23 +00:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: have io_waitid_complete() remove wait queue entry Both callers of this need the entry potentially removed, so shift the removal into the completion side and kill it from the two callers. While at it, add a helper for removing the wait_queue_entry based on the passed in io_kiocb. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 07:33:36 -06:00
io_uring/waitid: fix KCSAN warning on io_waitid->head Storing of the iw->head entry inside the wait_queue callback, or when removing a waitid item, really should use proper load/store acquire/release semantics, and KCSAN correctly warns of that. Ensure that they do so. Reported-by: syzbot+eb441775f4f948a0902f@syzkaller.appspotmail.com Fixes: a48c0cbf28c0 ("io_uring/waitid: have io_waitid_complete() remove wait queue entry") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-19 19:46:26 -07:00
io_uring/waitid: have io_waitid_complete() remove wait queue entry Both callers of this need the entry potentially removed, so shift the removal into the completion side and kill it from the two callers. While at it, add a helper for removing the wait_queue_entry based on the passed in io_kiocb. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 07:33:36 -06:00
io_uring/waitid: fix KCSAN warning on io_waitid->head Storing of the iw->head entry inside the wait_queue callback, or when removing a waitid item, really should use proper load/store acquire/release semantics, and KCSAN correctly warns of that. Ensure that they do so. Reported-by: syzbot+eb441775f4f948a0902f@syzkaller.appspotmail.com Fixes: a48c0cbf28c0 ("io_uring/waitid: have io_waitid_complete() remove wait queue entry") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-19 19:46:26 -07:00
io_uring/waitid: have io_waitid_complete() remove wait queue entry Both callers of this need the entry potentially removed, so shift the removal into the completion side and kill it from the two callers. While at it, add a helper for removing the wait_queue_entry based on the passed in io_kiocb. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 07:33:36 -06:00
io_uring/waitid: honor task_work cancellation io_waitid_cb() may run through the fallback task_work path when task_work_add() can no longer queue work to the originating task. The fallback runs from a kworker and io_uring marks such task work as canceled through tw.cancel. io_waitid_cb() currently ignores tw.cancel and calls __do_wait(). waitid is task-context dependent: __do_wait() performs child lookup relative to current, and the retry path also uses current->signal->wait_chldexit. If the callback runs from the fallback kworker, current is therefore not the task that submitted the request. Honor tw.cancel before entering __do_wait(). Complete the request with -ECANCELED and skip the siginfo copy, since canceled task work may run without the submitting task's userspace execution context. Keep the existing siginfo handling for normal waitid completion and explicit cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-2-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:36 +08:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: have io_waitid_complete() remove wait queue entry Both callers of this need the entry potentially removed, so shift the removal into the completion side and kill it from the two callers. While at it, add a helper for removing the wait_queue_entry based on the passed in io_kiocb. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 07:33:36 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: honor task_work cancellation io_waitid_cb() may run through the fallback task_work path when task_work_add() can no longer queue work to the originating task. The fallback runs from a kworker and io_uring marks such task work as canceled through tw.cancel. io_waitid_cb() currently ignores tw.cancel and calls __do_wait(). waitid is task-context dependent: __do_wait() performs child lookup relative to current, and the retry path also uses current->signal->wait_chldexit. If the callback runs from the fallback kworker, current is therefore not the task that submitted the request. Honor tw.cancel before entering __do_wait(). Complete the request with -ECANCELED and skip the siginfo copy, since canceled task work may run without the submitting task's userspace execution context. Keep the existing siginfo handling for normal waitid completion and explicit cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-2-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:36 +08:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: avoid siginfo copy during ring teardown During ring teardown, io_ring_exit_work() cancels outstanding requests from a kworker with a NULL tctx. The waitid cancellation path eventually reaches io_waitid_finish(), which copies the stored siginfo to the userspace pointer supplied with the request. Ring-wide teardown does not run in the task context that submitted the request, so it must not access that task's userspace pointer. Depending on the address and mm state, the copy may fail with -EFAULT, but the uaccess itself is inappropriate from the teardown kworker. Use a no-copy cancellation callback when io_waitid_remove_all() is called without an owning task context. Complete the request with -ECANCELED while releasing the waitid state without touching siginfo. Keep the existing siginfo handling for explicit async cancellation and task-scoped cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-3-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:37 +08:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: have io_waitid_complete() remove wait queue entry Both callers of this need the entry potentially removed, so shift the removal into the completion side and kill it from the two callers. While at it, add a helper for removing the wait_queue_entry based on the passed in io_kiocb. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 07:33:36 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: avoid siginfo copy during ring teardown During ring teardown, io_ring_exit_work() cancels outstanding requests from a kworker with a NULL tctx. The waitid cancellation path eventually reaches io_waitid_finish(), which copies the stored siginfo to the userspace pointer supplied with the request. Ring-wide teardown does not run in the task context that submitted the request, so it must not access that task's userspace pointer. Depending on the address and mm state, the copy may fail with -EFAULT, but the uaccess itself is inappropriate from the teardown kworker. Use a no-copy cancellation callback when io_waitid_remove_all() is called without an owning task context. Complete the request with -ECANCELED while releasing the waitid state without touching siginfo. Keep the existing siginfo handling for explicit async cancellation and task-scoped cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-3-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:37 +08:00
io_uring/waitid: don't abuse io_tw_state struct io_tw_state is managed by core io_uring, and opcode handling code must never try to cheat and create their own instances, it's plain incorrect. io_waitid_complete() attempts exactly that outside of the task work context, and even though the ring is locked, there would be no one to reap the requests from the defer completion list. It only works now because luckily it's called before io_uring_try_cancel_uring_cmd(), which flushes completions. Fixes: f31ecf671ddc4 ("io_uring: add IORING_OP_WAITID support") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-12 13:33:24 +00:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: avoid siginfo copy during ring teardown During ring teardown, io_ring_exit_work() cancels outstanding requests from a kworker with a NULL tctx. The waitid cancellation path eventually reaches io_waitid_finish(), which copies the stored siginfo to the userspace pointer supplied with the request. Ring-wide teardown does not run in the task context that submitted the request, so it must not access that task's userspace pointer. Depending on the address and mm state, the copy may fail with -EFAULT, but the uaccess itself is inappropriate from the teardown kworker. Use a no-copy cancellation callback when io_waitid_remove_all() is called without an owning task context. Complete the request with -ECANCELED while releasing the waitid state without touching siginfo. Keep the existing siginfo handling for explicit async cancellation and task-scoped cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-3-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:37 +08:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: avoid siginfo copy during ring teardown During ring teardown, io_ring_exit_work() cancels outstanding requests from a kworker with a NULL tctx. The waitid cancellation path eventually reaches io_waitid_finish(), which copies the stored siginfo to the userspace pointer supplied with the request. Ring-wide teardown does not run in the task context that submitted the request, so it must not access that task's userspace pointer. Depending on the address and mm state, the copy may fail with -EFAULT, but the uaccess itself is inappropriate from the teardown kworker. Use a no-copy cancellation callback when io_waitid_remove_all() is called without an owning task context. Complete the request with -ECANCELED while releasing the waitid state without touching siginfo. Keep the existing siginfo handling for explicit async cancellation and task-scoped cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-3-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:37 +08:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: move cancelations to be io_uring_task based Right now the task_struct pointer is used as the key to match a task, but in preparation for some io_kiocb changes, move it to using struct io_uring_task instead. No functional changes intended in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-03 10:22:43 -07:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: avoid siginfo copy during ring teardown During ring teardown, io_ring_exit_work() cancels outstanding requests from a kworker with a NULL tctx. The waitid cancellation path eventually reaches io_waitid_finish(), which copies the stored siginfo to the userspace pointer supplied with the request. Ring-wide teardown does not run in the task context that submitted the request, so it must not access that task's userspace pointer. Depending on the address and mm state, the copy may fail with -EFAULT, but the uaccess itself is inappropriate from the teardown kworker. Use a no-copy cancellation callback when io_waitid_remove_all() is called without an owning task context. Complete the request with -ECANCELED while releasing the waitid state without touching siginfo. Keep the existing siginfo handling for explicit async cancellation and task-scoped cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-3-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:37 +08:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: use io_waitid_remove_wq() consistently Use it everywhere that the wait_queue_entry is removed from the head, and be a bit more cautious in zeroing out iw->head whenever the entry is removed from the list. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 10:55:08 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: add wrapper type for io_req_tw_func_t arg In preparation for uring_cmd implementations to implement functions with the io_req_tw_func_t signature, introduce a wrapper struct io_tw_req to hide the struct io_kiocb * argument. The intention is for only the io_uring core to access the inner struct io_kiocb *. uring_cmd implementations should instead call a helper from io_uring/cmd.h to convert struct io_tw_req to struct io_uring_cmd *. Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-31 14:34:29 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: add wrapper type for io_req_tw_func_t arg In preparation for uring_cmd implementations to implement functions with the io_req_tw_func_t signature, introduce a wrapper struct io_tw_req to hide the struct io_kiocb * argument. The intention is for only the io_uring core to access the inner struct io_kiocb *. uring_cmd implementations should instead call a helper from io_uring/cmd.h to convert struct io_tw_req to struct io_uring_cmd *. Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-31 14:34:29 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: introduce type alias for io_tw_state In preparation for changing how io_tw_state is passed, introduce a type alias io_tw_token_t for struct io_tw_state *. This allows for changing the representation in one place, without having to update the many functions that just forward their struct io_tw_state * argument. Also add a comment to struct io_tw_state to explain its purpose. Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Link: https://lore.kernel.org/r/20250217022511.1150145-1-csander@purestorage.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-16 19:25:04 -07:00
io_uring/waitid: honor task_work cancellation io_waitid_cb() may run through the fallback task_work path when task_work_add() can no longer queue work to the originating task. The fallback runs from a kworker and io_uring marks such task work as canceled through tw.cancel. io_waitid_cb() currently ignores tw.cancel and calls __do_wait(). waitid is task-context dependent: __do_wait() performs child lookup relative to current, and the retry path also uses current->signal->wait_chldexit. If the callback runs from the fallback kworker, current is therefore not the task that submitted the request. Honor tw.cancel before entering __do_wait(). Complete the request with -ECANCELED and skip the siginfo copy, since canceled task work may run without the submitting task's userspace execution context. Keep the existing siginfo handling for normal waitid completion and explicit cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-2-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:36 +08:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: have io_waitid_complete() remove wait queue entry Both callers of this need the entry potentially removed, so shift the removal into the completion side and kill it from the two callers. While at it, add a helper for removing the wait_queue_entry based on the passed in io_kiocb. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 07:33:36 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: honor task_work cancellation io_waitid_cb() may run through the fallback task_work path when task_work_add() can no longer queue work to the originating task. The fallback runs from a kworker and io_uring marks such task work as canceled through tw.cancel. io_waitid_cb() currently ignores tw.cancel and calls __do_wait(). waitid is task-context dependent: __do_wait() performs child lookup relative to current, and the retry path also uses current->signal->wait_chldexit. If the callback runs from the fallback kworker, current is therefore not the task that submitted the request. Honor tw.cancel before entering __do_wait(). Complete the request with -ECANCELED and skip the siginfo copy, since canceled task work may run without the submitting task's userspace execution context. Keep the existing siginfo handling for normal waitid completion and explicit cancellation. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org Signed-off-by: Hui Su <sh_def@163.com> Link: https://patch.msgid.link/20260818103336.1922818-2-sh_def@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-18 18:33:36 +08:00
io_uring: add wrapper type for io_req_tw_func_t arg In preparation for uring_cmd implementations to implement functions with the io_req_tw_func_t signature, introduce a wrapper struct io_tw_req to hide the struct io_kiocb * argument. The intention is for only the io_uring core to access the inner struct io_kiocb *. uring_cmd implementations should instead call a helper from io_uring/cmd.h to convert struct io_tw_req to struct io_uring_cmd *. Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-31 14:34:29 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: always prune wait queue entry in io_waitid_wait() For a successful return, always remove our entry from the wait queue entry list. Previously this was skipped if a cancelation was in progress, but this can race with another invocation of the wait queue entry callback. Cc: stable@vger.kernel.org Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Reported-by: syzbot+b9e83021d9c642a33d8c@syzkaller.appspotmail.com Tested-by: syzbot+b9e83021d9c642a33d8c@syzkaller.appspotmail.com Link: https://lore.kernel.org/io-uring/68e5195e.050a0220.256323.001f.GAE@google.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-07 07:46:00 -06:00
io_uring/waitid: fix KCSAN warning on io_waitid->head Storing of the iw->head entry inside the wait_queue callback, or when removing a waitid item, really should use proper load/store acquire/release semantics, and KCSAN correctly warns of that. Ensure that they do so. Reported-by: syzbot+eb441775f4f948a0902f@syzkaller.appspotmail.com Fixes: a48c0cbf28c0 ("io_uring/waitid: have io_waitid_complete() remove wait queue entry") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-19 19:46:26 -07:00
io_uring/waitid: always prune wait queue entry in io_waitid_wait() For a successful return, always remove our entry from the wait queue entry list. Previously this was skipped if a cancelation was in progress, but this can race with another invocation of the wait queue entry callback. Cc: stable@vger.kernel.org Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Reported-by: syzbot+b9e83021d9c642a33d8c@syzkaller.appspotmail.com Tested-by: syzbot+b9e83021d9c642a33d8c@syzkaller.appspotmail.com Link: https://lore.kernel.org/io-uring/68e5195e.050a0220.256323.001f.GAE@google.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-07 07:46:00 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: defer eventfd signaling when queued from a wakeup handler io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline. Fixes: 21a091b970cd ("io_uring: signal registered eventfd to process deferred task work") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20260813133843.2933127-1-4ncienth@gmail.com/ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-08-14 06:58:43 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: setup async data in the prep handler This is the idiomatic way that opcodes should setup their async data, so that it's always valid inside ->issue() without issue needing to do that. Fixes: f31ecf671ddc4 ("io_uring: add IORING_OP_WAITID support") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-12 15:52:54 -07:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: setup async data in the prep handler This is the idiomatic way that opcodes should setup their async data, so that it's always valid inside ->issue() without issue needing to do that. Fixes: f31ecf671ddc4 ("io_uring: add IORING_OP_WAITID support") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-12 15:52:54 -07:00
io_uring: fix incorrect unlikely() usage in io_waitid_prep() The negation operator is incorrectly placed outside the unlikely() macro: if (!unlikely(iwa)) This inverts the compiler branch prediction hint, marking the NULL case as likely instead of unlikely. The intent is to indicate that allocation failures are rare, consistent with common kernel patterns. Moving the negation inside unlikely(): if (unlikely(!iwa)) Fixes: 2b4fc4cd43f2 ("io_uring/waitid: setup async data in the prep handler") Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com> Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Reviewed-by: Caleb Sander Mateos <csander@purestorage.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-18 12:32:54 -07:00
io_uring/waitid: setup async data in the prep handler This is the idiomatic way that opcodes should setup their async data, so that it's always valid inside ->issue() without issue needing to do that. Fixes: f31ecf671ddc4 ("io_uring: add IORING_OP_WAITID support") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-12 15:52:54 -07:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: use io_waitid_remove_wq() consistently Use it everywhere that the wait_queue_entry is removed from the head, and be a bit more cautious in zeroing out iw->head whenever the entry is removed from the list. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 10:55:08 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: clear waitid info before copying it to userspace IORING_OP_WAITID stores its result fields in struct io_waitid::info and later copies them to userspace siginfo. The prep path initializes the request arguments, but it does not initialize info itself. If the wait operation completes without reporting a child event, the common wait code can return without writing wo_info. In that case io_waitid_finish() still copies iw->info to userspace, exposing stale bytes from the reused io_kiocb command storage. Clear the result storage during prep so the io_uring path matches the regular waitid syscall, which uses a zero-initialized struct waitid_info. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org # 6.7+ Signed-off-by: Heechan Kang <gganji11@naver.com> Link: https://patch.msgid.link/20260516184709.852814-1-gganji11@naver.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-17 03:47:09 +09:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: setup async data in the prep handler This is the idiomatic way that opcodes should setup their async data, so that it's always valid inside ->issue() without issue needing to do that. Fixes: f31ecf671ddc4 ("io_uring: add IORING_OP_WAITID support") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-12 15:52:54 -07:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: use io_waitid_remove_wq() consistently Use it everywhere that the wait_queue_entry is removed from the head, and be a bit more cautious in zeroing out iw->head whenever the entry is removed from the list. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 10:55:08 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: move struct io_kiocb from task_struct to io_uring_task Rather than store the task_struct itself in struct io_kiocb, store the io_uring specific task_struct. The life times are the same in terms of io_uring, and this avoids doing some dereferences through the task_struct. For the hot path of putting local task references, we can deref req->tctx instead, which we'll need anyway in that function regardless of whether it's local or remote references. This is mostly straight forward, except the original task PF_EXITING check needs a bit of tweaking. task_work is _always_ run from the originating task, except in the fallback case, where it's run from a kernel thread. Replace the potentially racy (in case of fallback work) checks for req->task->flags with current->flags. It's either the still the original task, in which case PF_EXITING will be sane, or it has PF_KTHREAD set, in which case it's fallback work. Both cases should prevent moving forward with the given request. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-03 10:23:38 -07:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring/waitid: use io_waitid_remove_wq() consistently Use it everywhere that the wait_queue_entry is removed from the head, and be a bit more cautious in zeroing out iw->head whenever the entry is removed from the list. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-09 10:55:08 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00
io_uring: finish IOU_OK -> IOU_COMPLETE transition IOU_COMPLETE is more descriptive, in that it explicitly says that the return value means "please post a completion for this request". This patch completes the transition from IOU_OK to IOU_COMPLETE, replacing existing IOU_OK users. This is a purely mechanical change. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-08 14:48:33 -06:00
io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-10 16:14:37 -06:00