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2023-06-23io_uring: make io_cq_unlock_post staticPavel Begunkov1-2/+0
io_cq_unlock_post() is exclusively used in io_uring/io_uring.c, mark it static and don't expose to other files. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3dc8127dda4514e1dd24bb32035faac887c5fa37.1687518903.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-23io_uring: remove IOU_F_TWQ_FORCE_NORMALPavel Begunkov1-4/+1
Extract a function for non-local task_work_add, and use it directly from io_move_task_work_from_local(). Now we don't use IOU_F_TWQ_FORCE_NORMAL and it can be killed. As a small positive side effect we don't grab task->io_uring in io_req_normal_work_add anymore, which is not needed for io_req_local_work_add(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2e55571e8ff2927ae3cc12da606d204e2485525b.1687518903.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-20io_uring: remove io_req_ffs_setChristoph Hellwig1-5/+0
Just checking the flag directly makes it a lot more obvious what is going on here. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230620113235.920399-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-07io_uring: cleanup io_aux_cqe() APIJens Axboe1-1/+1
Everybody is passing in the request, so get rid of the io_ring_ctx and explicit user_data pass-in. Both the ctx and user_data can be deduced from the request at hand. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-16io_uring: Add io_uring_setup flag to pre-register ring fd and never install itJosh Triplett1-0/+3
With IORING_REGISTER_USE_REGISTERED_RING, an application can register the ring fd and use it via registered index rather than installed fd. This allows using a registered ring for everything *except* the initial mmap. With IORING_SETUP_NO_MMAP, io_uring_setup uses buffers allocated by the user, rather than requiring a subsequent mmap. The combination of the two allows a user to operate *entirely* via a registered ring fd, making it unnecessary to ever install the fd in the first place. So, add a flag IORING_SETUP_REGISTERED_FD_ONLY to make io_uring_setup register the fd and return a registered index, without installing the fd. This allows an application to avoid touching the fd table at all, and allows a library to never even momentarily install a file descriptor. This splits out an io_ring_add_registered_file helper from io_ring_add_registered_fd, for use by io_uring_setup. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Link: https://lore.kernel.org/r/bc8f431bada371c183b95a83399628b605e978a3.1682699803.git.josh@joshtriplett.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-04io_uring: Create a helper to return the SQE sizeBreno Leitao1-0/+10
Create a simple helper that returns the size of the SQE. The SQE could have two size, depending of the flags. If IO_URING_SETUP_SQE128 flag is set, then return a double SQE, otherwise returns the sizeof of io_uring_sqe (64 bytes). Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20230504121856.904491-2-leitao@debian.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-12io_uring: add irq lockdep checksPavel Begunkov1-0/+2
We don't post CQEs from the IRQ context, add a check catching that. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/f23f7a24dbe8027b3d37873fece2b6488f878b31.1681210788.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-07io_uring: reduce scheduling due to twPavel Begunkov1-0/+9
Every task_work will try to wake the task to be executed, which causes excessive scheduling and additional overhead. For some tw it's justified, but others won't do much but post a single CQE. When a task waits for multiple cqes, every such task_work will wake it up. Instead, the task may give a hint about how many cqes it waits for, io_req_local_work_add() will compare against it and skip wake ups if #cqes + #tw is not enough to satisfy the waiting condition. Task_work that uses the optimisation should be simple enough and never post more than one CQE. It's also ignored for non DEFER_TASKRUN rings. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d2b77e99d1e86624d8a69f7037d764b739dcd225.1680782017.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-07io_uring: add tw add flagsPavel Begunkov1-2/+7
We pass 'allow_local' into io_req_task_work_add() but will need more flags. Replace it with a flags bit field and name this allow_local flag. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/4c0f01e7ef4e6feebfb199093cc995af7a19befa.1680782017.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-07io_uring: refactor io_cqring_wake()Pavel Begunkov1-9/+2
Instead of smp_mb() + __io_cqring_wake() in __io_cq_unlock_post_flush() use equivalent io_cqring_wake(). With that we can clean it up further and remove __io_cqring_wake(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/662ee5d898168ac206be06038525e97b64072a46.1680782017.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-03io_uring: cap io_sqring_entries() at SQ ring sizeJens Axboe1-1/+3
We already do this manually for the !SQPOLL case, do it in general and we can also dump the ugly min3() in io_submit_sqes(). Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-03io_uring: encapsulate task_work statePavel Begunkov1-7/+7
For task works we're passing around a bool pointer for whether the current ring is locked or not, let's wrap it in a structure, that will make it more opaque preventing abuse and will also help us to pass more info in the future if needed. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/1ecec9483d58696e248d1bfd52cf62b04442df1d.1679931367.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-06io_uring: mark task TASK_RUNNING before handling resume/task workJens Axboe1-1/+3
Just like for task_work, set the task mode to TASK_RUNNING before doing any potential resume work. We're not holding any locks at this point, but we may have already set the task state to TASK_INTERRUPTIBLE in preparation for going to sleep waiting for events. Ensure that we set it back to TASK_RUNNING if we have work to process, to avoid warnings on calling blocking operations with !TASK_RUNNING. Fixes: b5d3ae202fbf ("io_uring: handle TIF_NOTIFY_RESUME when checking for task_work") Reported-by: kernel test robot <oliver.sang@intel.com> Link: https://lore.kernel.org/oe-lkp/202302062208.24d3e563-oliver.sang@intel.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: refactor req allocationPavel Begunkov1-8/+11
Follow the io_get_sqe pattern returning the result via a pointer and hide request cache refill inside io_alloc_req(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8c37c2e8a3cb5e4cd6a8ae3b91371227a92708a6.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: Enable KASAN for request cacheBreno Leitao1-3/+8
Every io_uring request is represented by struct io_kiocb, which is cached locally by io_uring (not SLAB/SLUB) in the list called submit_state.freelist. This patch simply enabled KASAN for this free list. This list is initially created by KMEM_CACHE, but later, managed by io_uring. This patch basically poisons the objects that are not used (i.e., they are the free list), and unpoisons it when the object is allocated/removed from the list. Touching these poisoned objects while in the freelist will cause a KASAN warning. Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: handle TIF_NOTIFY_RESUME when checking for task_workJens Axboe1-0/+8
If TIF_NOTIFY_RESUME is set, then we need to call resume_user_mode_work() for PF_IO_WORKER threads. They never return to usermode, hence never get a chance to process any items that are marked by this flag. Most notably this includes the final put of files, but also any throttling markers set by block cgroups. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: don't export io_put_task()Pavel Begunkov1-10/+0
io_put_task() is only used in uring.c so enclose it there together with __io_put_task(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/43c7f9227e2ab215f1a6069dadbc5382bed346fe.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: add lazy poll_wq activationPavel Begunkov1-4/+3
Even though io_poll_wq_wake()'s waitqueue_active reuses a barrier we do for another waitqueue, it's not going to be the case in the future and so we want to have a fast path for it when the ring has never been polled. Move poll_wq wake ups into __io_commit_cqring_flush() using a new flag called ->poll_activated. The idea behind the flag is to set it when the ring was polled for the first time. This requires additional sync to not miss events, which is done here by using task_work for ->task_complete rings, and by default enabling the flag for all other types of rings. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/060785e8e9137a920b232c0c7f575b131af19cac.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: separate wq for ring pollingPavel Begunkov1-0/+9
Don't use ->cq_wait for ring polling but add a separate wait queue for it. We need it for following patches. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/dea0be0bf990503443c5c6c337fc66824af7d590.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: move io_run_local_work_lockedPavel Begunkov1-17/+0
io_run_local_work_locked() is only used in io_uring.c, move it there. With that we can also make __io_run_local_work() static. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/91757bcb33e5774e49fed6f2b6e058630608119b.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: mark io_run_local_work staticPavel Begunkov1-1/+0
io_run_local_work is enclosed in io_uring.c, we don't need to export it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b477fb81f5e77044f724a06fe245d5c078659364.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: move defer tw task checksPavel Begunkov1-0/+5
Most places that want to run local tw explicitly and in advance check if they are allowed to do so. Don't rely on a similar check in __io_run_local_work(), leave it as a just-in-case warning and make sure callers checks capabilities themselves. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/990fe0e8e70fd4d57e43625e5ce8fba584821d1a.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: kill io_run_task_work_ctxPavel Begunkov1-20/+0
There is only one user of io_run_task_work_ctx(), inline it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/40953c65f7c88fb00cdc4d870ca5d5319fb3d7ea.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: rearrange defer list checksPavel Begunkov1-1/+1
There should be nothing in the ->work_llist for non DEFER_TASKRUN rings, so we can skip flag checks and test the list emptiness directly. Also move it out of io_run_local_work() for inlining. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/331d63fd15ca79b35b95c82a82d9246110686392.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-04io_uring: lockdep annotate CQ lockingPavel Begunkov1-0/+15
Locking around CQE posting is complex and depends on options the ring is created with, add more thorough lockdep annotations checking all invariants. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/aa3770b4eacae3915d782cc2ab2f395a99b4b232.1672795976.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-17io_uring: don't use TIF_NOTIFY_SIGNAL to test for availability of task_workJens Axboe1-2/+1
Use task_work_pending() as a better test for whether we have task_work or not, TIF_NOTIFY_SIGNAL is only valid if the any of the task_work items had been queued with TWA_SIGNAL as the notification mechanism. Hence task_work_pending() is a more reliable check. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-14io_uring: revise completion_lock lockingPavel Begunkov1-11/+0
io_kill_timeouts() doesn't post any events but queues everything to task_work. Locking there is needed for protecting linked requests traversing, we should grab completion_lock directly instead of using io_cq_[un]lock helpers. Same goes for __io_req_find_next_prep(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/88e75d481a65dc295cb59722bb1cf76402d1c06b.1670002973.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-07io_uring: skip spinlocking for ->task_completePavel Begunkov1-1/+9
->task_complete was added to serialised CQE posting by doing it from the task context only (or fallback wq when the task is dead), and now we can use that to avoid taking ->completion_lock while filling CQ entries. The patch skips spinlocking only in two spots, __io_submit_flush_completions() and flushing in io_aux_cqe, it's safer and covers all cases we care about. Extra care is taken to force taking the lock while queueing overflow entries. It fundamentally relies on SINGLE_ISSUER to have only one task posting events. It also need to take into account overflowed CQEs, flushing of which happens in the cq wait path, and so this implementation also needs DEFER_TASKRUN to limit waiters. For the same reason we disable it for SQPOLL, and for IOPOLL as it won't benefit from it in any case. DEFER_TASKRUN, SQPOLL and IOPOLL requirement may be relaxed in the future. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2a8c91fd82cfcdcc1d2e5bac7051fe2c183bda73.1670384893.git.asml.silence@gmail.com [axboe: modify to apply] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-30io_uring: don't raw spin unlock to match cq_lockPavel Begunkov1-0/+5
There is one newly added place when we lock ring with io_cq_lock() but unlocking is hand coded calling spin_unlock directly. It's ugly and troublesome in the long run. Make it consistent with the other completion locking. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/4ca4f0564492b90214a190cd5b2a6c76522de138.1669821213.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-29Merge branch 'for-6.2/io_uring' into for-6.2/io_uring-nextJens Axboe1-14/+29
* for-6.2/io_uring: (41 commits) io_uring: keep unlock_post inlined in hot path io_uring: don't use complete_post in kbuf io_uring: spelling fix io_uring: remove io_req_complete_post_tw io_uring: allow multishot polled reqs to defer completion io_uring: remove overflow param from io_post_aux_cqe io_uring: add lockdep assertion in io_fill_cqe_aux io_uring: make io_fill_cqe_aux static io_uring: add io_aux_cqe which allows deferred completion io_uring: allow defer completion for aux posted cqes io_uring: defer all io_req_complete_failed io_uring: always lock in io_apoll_task_func io_uring: remove iopoll spinlock io_uring: iopoll protect complete_post io_uring: inline __io_req_complete_put() io_uring: remove io_req_tw_post_queue io_uring: use io_req_task_complete() in timeout io_uring: hold locks for io_req_complete_failed io_uring: add completion locking for iopoll io_uring: kill io_cqring_ev_posted() and __io_cq_unlock_post() ...
2022-11-25io_uring: clear TIF_NOTIFY_SIGNAL if set and task_work not availableJens Axboe1-2/+7
With how task_work is added and signaled, we can have TIF_NOTIFY_SIGNAL set and no task_work pending as it got run in a previous loop. Treat TIF_NOTIFY_SIGNAL like get_signal(), always clear it if set regardless of whether or not task_work is pending to run. Cc: stable@vger.kernel.org Fixes: 46a525e199e4 ("io_uring: don't gate task_work run on TIF_NOTIFY_SIGNAL") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-25io_uring: remove io_req_complete_post_twDylan Yudaken1-7/+0
It's only used in one place. Inline it. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20221125103412.1425305-2-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-25io_uring: remove overflow param from io_post_aux_cqeDylan Yudaken1-2/+1
The only call sites which would not allow overflow are also call sites which would use the io_aux_cqe as they care about ordering. So remove this parameter from io_post_aux_cqe. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20221124093559.3780686-9-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-25io_uring: make io_fill_cqe_aux staticDylan Yudaken1-2/+0
This is only used in io_uring.c Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20221124093559.3780686-7-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-25io_uring: add io_aux_cqe which allows deferred completionDylan Yudaken1-0/+2
Use the just introduced deferred post cqe completion state when possible in io_aux_cqe. If not possible fallback to io_post_aux_cqe. This introduces a complication because of allow_overflow. For deferred completions we cannot know without locking the completion_lock if it will overflow (and even if we locked it, another post could sneak in and cause this cqe to be in overflow). However since overflow protection is mostly a best effort defence in depth to prevent infinite loops of CQEs for poll, just checking the overflow bit is going to be good enough and will result in at most 16 (array size of deferred cqes) overflows. Suggested-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20221124093559.3780686-6-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-25io_uring: defer all io_req_complete_failedDylan Yudaken1-1/+1
All failures happen under lock now, and can be deferred. To be consistent when the failure has happened after some multishot cqe has been deferred (and keep ordering), always defer failures. To make this obvious at the caller (and to help prevent a future bug) rename io_req_complete_failed to io_req_defer_failed. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20221124093559.3780686-4-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-23io_uring: iopoll protect complete_postPavel Begunkov1-2/+8
io_req_complete_post() may be used by iopoll enabled rings, grab locks in this case. That requires to pass issue_flags to propagate the locking state. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/cc6d854065c57c838ca8e8806f707a226b70fd2d.1669203009.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-23io_uring: remove io_req_tw_post_queuePavel Begunkov1-1/+7
Remove io_req_tw_post() and io_req_tw_post_queue(), we can use io_req_task_complete() instead. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b9b73c08022c7f1457023ac841f35c0100e70345.1669203009.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-22io_uring: pass in EPOLL_URING_WAKE for eventfd signaling and wakeupsJens Axboe1-4/+11
Pass in EPOLL_URING_WAKE when signaling eventfd or doing poll related wakups, so that we can check for a circular event dependency between eventfd and epoll. If this flag is set when our wakeup handlers are called, then we know we have a dependency that needs to terminate multishot requests. eventfd and epoll are the only such possible dependencies. Cc: stable@vger.kernel.org # 6.0 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21io_uring: inline __io_req_complete_post()Pavel Begunkov1-1/+0
There is only one user of __io_req_complete_post(), inline it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/ef4c9059950a3da5cf68df00f977f1fd13bd9306.1668597569.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21io_uring: inline io_req_task_work_add()Pavel Begunkov1-1/+6
__io_req_task_work_add() is huge but marked inline, that makes compilers to generate lots of garbage. Inline the wrapper caller io_req_task_work_add() instead. before and after: text data bss dec hex filename 47347 16248 8 63603 f873 io_uring/io_uring.o text data bss dec hex filename 45303 16248 8 61559 f077 io_uring/io_uring.o Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/26dc8c28ca0160e3269ef3e55c5a8b917c4d4450.1668162751.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-17io_uring: fix multishot accept request leaksPavel Begunkov1-2/+2
Having REQ_F_POLLED set doesn't guarantee that the request is executed as a multishot from the polling path. Fortunately for us, if the code thinks it's multishot issue when it's not, it can only ask to skip completion so leaking the request. Use issue_flags to mark multipoll issues. Cc: stable@vger.kernel.org Fixes: 390ed29b5e425 ("io_uring: add IORING_ACCEPT_MULTISHOT for accept") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/7700ac57653f2823e30b34dc74da68678c0c5f13.1668710222.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-27io_uring: unlock if __io_run_local_work locked insideDylan Yudaken1-2/+11
It is possible for tw to lock the ring, and this was not propogated out to io_run_local_work. This can cause an unlock to be missed. Instead pass a pointer to locked into __io_run_local_work. Fixes: 8ac5d85a89b4 ("io_uring: add local task_work run helper that is entered locked") Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20221027144429.3971400-3-dylany@meta.com [axboe: WARN_ON() -> WARN_ON_ONCE() and add a minor comment] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-13io_uring: optimise locking for local tw with submit_waitPavel Begunkov1-0/+7
Running local task_work requires taking uring_lock, for submit + wait we can try to run them right after submit while we still hold the lock and save one lock/unlokc pair. The optimisation was implemented in the first local tw patches but got dropped for simplicity. Suggested-by: Dylan Yudaken <dylany@fb.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/281fc79d98b5d91fe4778c5137a17a2ab4693e5c.1665088876.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-13io_uring: remove redundant memory barrier in io_req_local_work_addPavel Begunkov1-2/+9
io_cqring_wake() needs a barrier for the waitqueue_active() check. However, in the case of io_req_local_work_add(), we call llist_add() first, which implies an atomic. Hence we can replace smb_mb() with smp_mb__after_atomic(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/43983bc8bc507172adda7a0f00cab1aff09fd238.1665018309.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-30io_uring: don't gate task_work run on TIF_NOTIFY_SIGNALJens Axboe1-4/+4
This isn't a reliable mechanism to tell if we have task_work pending, we really should be looking at whether we have any items queued. This is problematic if forward progress is gated on running said task_work. One such example is reading from a pipe, where the write side has been closed right before the read is started. The fput() of the file queues TWA_RESUME task_work, and we need that task_work to be run before ->release() is called for the pipe. If ->release() isn't called, then the read will sit forever waiting on data that will never arise. Fix this by io_run_task_work() so it checks if we have task_work pending rather than rely on TIF_NOTIFY_SIGNAL for that. The latter obviously doesn't work for task_work that is queued without TWA_SIGNAL. Reported-by: Christiano Haesbaert <haesbaert@haesbaert.org> Cc: stable@vger.kernel.org Link: https://github.com/axboe/liburing/issues/665 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-24io_uring: fix CQE reorderingPavel Begunkov1-3/+9
Overflowing CQEs may result in reordering, which is buggy in case of links, F_MORE and so on. If we guarantee that we don't reorder for the unlikely event of a CQ ring overflow, then we can further extend this to not have to terminate multishot requests if it happens. For other operations, like zerocopy sends, we have no choice but to honor CQE ordering. Reported-by: Dylan Yudaken <dylany@fb.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/ec3bc55687b0768bbe20fb62d7d06cfced7d7e70.1663892031.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-21io_uring: disallow defer-tw run w/ no submittersPavel Begunkov1-7/+2
We try to restrict CQ waiters when IORING_SETUP_DEFER_TASKRUN is set, but if nothing has been submitted yet it'll allow any waiter, which violates the contract. 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/b4f0d3f14236d7059d08c5abe2661ef0b78b5528.1662652536.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-21io_uring: further limit non-owner defer-tw cq waitingPavel Begunkov1-0/+11
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>
2022-09-21io_uring: ensure iopoll runs local task work as wellJens Axboe1-0/+6
Combine the two checks we have for task_work running and whether or not we need to shuffle the mutex into one, so we unify how task_work is run in the iopoll loop. This helps ensure that local task_work is run when needed, and also optimizes that path to avoid a mutex shuffle if it's not needed. Signed-off-by: Jens Axboe <axboe@kernel.dk>
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