summaryrefslogtreecommitdiff
AgeCommit message (Collapse)Author
2021-02-18io_uring: split sqe-prep and async setupPavel Begunkov
There are two kinds of opcode-specific preparations we do. The first is just initialising req with what is always needed for an opcode and reading all non-generic SQE fields. And the second is copying some of the stuff like iovec preparing to punt a request to somewhere async, e.g. to io-wq or for draining. For requests that have tried an inline execution but still needing to be punted, the second prep type is done by the opcode handler itself. Currently, we don't explicitly split those preparation steps, but combining both of them into io_*_prep(), altering the behaviour by allocating ->async_data. That's pretty messy and hard to follow and also gets in the way of some optimisations. Split the steps, leave the first type as where it is now, and put the second into a new io_req_prep_async() helper. It may make us to do opcode switch twice, but it's worth it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-18io_uring: don't submit link on errorPavel Begunkov
If we get an error in io_init_req() for a request that would have been linked, we break the submission but still issue a partially composed link, that's nasty, fail it instead. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-18io_uring: move req link into submit_statePavel Begunkov
Move struct io_submit_link into submit_state, which is a part of a submission state and so belongs to it. It saves us from explicitly passing it, and init/deinit is now nicely hidden in io_submit_state_[start,end]. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-18io_uring: move io_init_req() into io_submit_sqe()Pavel Begunkov
Behaves identically, just move io_init_req() call into the beginning of io_submit_sqes(). That looks better unloads io_submit_sqes(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-18io_uring: move io_init_req()'s definitionPavel Begunkov
A preparation patch, symbol to symbol move io_init_req() + io_check_restriction() a bit up. The submission path is pretty settled down, so don't worry about backports and move the functions instead of relying on forward declarations in the future. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-18io_uring: don't duplicate ->file check in sfrPavel Begunkov
IORING_OP_SYNC_FILE_RANGE is marked as .needs_file, so the common path will take care of assigning and validating req->file, no need to duplicate it in io_sfr_prep(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-18io_uring: keep io_*_prep() naming consistentPavel Begunkov
Follow io_*_prep() naming pattern, there are only fsync and sfr that don't do that. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-18io_uring: kill fictitious submit iteration indexPavel Begunkov
@i and @submitted are very much coupled together, and there is no need to keep them both. Remove @i, it doesn't change generated binary but helps to keep a single source of truth. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-17io_uring: fix read memory leakPavel Begunkov
Don't forget to free iovec read inline completion and bunch of other cases that do "goto done" before setting up an async context. Fixes: 5ea5dd45844d ("io_uring: inline io_read()'s iovec freeing") Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-16io_uring: tctx->task_lock should be IRQ safeJens Axboe
We add task_work from any context, hence we need to ensure that we can tolerate it being from IRQ context as well. Fixes: 7cbf1722d5fc ("io_uring: provide FIFO ordering for task_work") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-15proc: don't allow async path resolution of /proc/thread-self componentsJens Axboe
If this is attempted by an io-wq kthread, then return -EOPNOTSUPP as we don't currently support that. Once we can get task_pid_ptr() doing the right thing, then this can go away again. Use PF_IO_WORKER for this to speciically target the io_uring workers. Modify the /proc/self/ check to use PF_IO_WORKER as well. Cc: stable@vger.kernel.org Fixes: 8d4c3e76e3be ("proc: don't allow async path resolution of /proc/self components") Reported-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-13io_uring: kill cached requests from exiting task closing the ringJens Axboe
Be nice and prune these upfront, in case the ring is being shared and one of the tasks is going away. This is a bit more important now that we account the allocations. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-13io_uring: add helper to free all request cachesJens Axboe
We have three different ones, put it in a helper for easy calling. This is in preparation for doing it outside of ring freeing as well. With that in mind, also ensure that we do the proper locking for safe calling from a context where the ring it still live. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-13io_uring: allow task match to be passed to io_req_cache_free()Jens Axboe
No changes in this patch, just allows a caller to pass in a targeted task that we must match for freeing requests in the cache. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io-wq: clear out worker ->fs and ->filesJens Axboe
By default, kernel threads have init_fs and init_files assigned. In the past, this has triggered security problems, as commands that don't ask for (and hence don't get assigned) fs/files from the originating task can then attempt path resolution etc with access to parts of the system they should not be able to. Rather than add checks in the fs code for misuse, just set these to NULL. If we do attempt to use them, then the resulting code will oops rather than provide access to something that it should not permit. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: optimise io_init_req() flags settingPavel Begunkov
Invalid req->flags are tolerated by free/put well, avoid this dancing needlessly presetting it to zero, and then not even resetting but modifying it, i.e. "|=". Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: clean io_req_find_next() fast checkPavel Begunkov
Indirectly io_req_find_next() is called for every request, optimise the check by testing flags as it was long before -- __io_req_find_next() tolerates false-positives well (i.e. link==NULL), and those should be really rare. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: don't check PF_EXITING from syscallPavel Begunkov
io_sq_thread_acquire_mm_files() can find a PF_EXITING task only when it's called from task_work context. Don't check it in all other cases, that are when we're in io_uring_enter(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: don't split out consume out of SQE getPavel Begunkov
Remove io_consume_sqe() and inline it back into io_get_sqe(). It requires req dealloc on error, but in exchange we get cleaner io_submit_sqes() and better locality for cached_sq_head. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: save ctx put/get for task_work submitPavel Begunkov
Do a little trick in io_ring_ctx_free() briefly taking uring_lock, that will wait for everyone currently holding it, so we can skip pinning ctx with ctx->refs for __io_req_task_submit(), which is executed and loses its refs/reqs while holding the lock. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: don't duplicate io_req_task_queue()Pavel Begunkov
Don't hand code io_req_task_queue() inside of io_async_buf_func(), just call it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: optimise SQPOLL mm/files grabbingPavel Begunkov
There are two reasons for this. First is to optimise io_sq_thread_acquire_mm_files() for non-SQPOLL case, which currently do too many checks and function calls in the hot path, e.g. in io_init_req(). The second is to not grab mm/files when there are not needed. As __io_queue_sqe() issues only one request now, we can reuse io_sq_thread_acquire_mm_files() instead of unconditional acquire mm/files. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: optimise out unlikely link queuePavel Begunkov
__io_queue_sqe() tries to issue as much requests of a link as it can, and uses io_put_req_find_next() to extract a next one, targeting inline completed requests. As now __io_queue_sqe() is always used together with struct io_comp_state, it leaves next propagation only a small window and only for async reqs, that doesn't justify its existence. Remove it, make __io_queue_sqe() to issue only a head request. It simplifies the code and will allow other optimisations. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-12io_uring: take compl state from submit statePavel Begunkov
Completion and submission states are now coupled together, it's weird to get one from argument and another from ctx, do it consistently for io_req_free_batch(). It's also faster as we already have @state cached in registers. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-11io_uring: inline io_complete_rw_common()Pavel Begunkov
__io_complete_rw() casts request to kiocb for it to be immediately container_of()'ed by io_complete_rw_common(). And the last function's name doesn't do a great job of illuminating its purposes, so just inline it in its only user. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-11io_uring: move res check out of io_rw_reissue()Pavel Begunkov
We pass return code into io_rw_reissue() only to be able to check if it's -EAGAIN. That's not the cleanest approach and may prevent inlining of the non-EAGAIN fast path, so do it at call sites. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-11io_uring: simplify iopoll reissuingPavel Begunkov
Don't stash -EAGAIN'ed iopoll requests into a list to reissue it later, do it eagerly. It removes overhead on keeping and checking that list, and allows in case of failure for these requests to be completed through normal iopoll completion path. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-11io_uring: clean up io_req_free_batch_finish()Pavel Begunkov
io_req_free_batch_finish() is final and does not permit struct req_batch to be reused without re-init. To be more consistent don't clear ->task there. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-11io_uring: move submit side state closer in the ringJens Axboe
We recently added the submit side req cache, but it was placed at the end of the struct. Move it near the other submission state for better memory placement, and reshuffle a few other members at the same time. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-11io_uring: assign file_slot prior to calling io_sqe_file_register()Jens Axboe
We use the assigned slot in io_sqe_file_register(), and a previous patch moved the assignment to after we have called it. This isn't super pretty, and will get cleaned up in the future. For now, fix the regression by restoring the previous assignment/clear of the file_slot. Fixes: ea64ec02b31d ("io_uring: deduplicate file table slot calculation") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: remove redundant initialization of variable retColin Ian King
The variable ret is being initialized with a value that is never read and it is being updated later with a new value. The initialization is redundant and can be removed. Addresses-Coverity: ("Unused value") Fixes: b63534c41e20 ("io_uring: re-issue block requests that failed because of resources") Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: unpark SQPOLL thread for cancelationPavel Begunkov
We park SQPOLL task before going into io_uring_cancel_files(), so the task won't run task_works including those that might be important for the cancellation passes. In this case it's io_poll_remove_one(), which frees requests via io_put_req_deferred(). Unpark it for while waiting, it's ok as we disable submissions beforehand, so no new requests will be generated. INFO: task syz-executor893:8493 blocked for more than 143 seconds. Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x90c/0x21a0 kernel/sched/core.c:5078 schedule+0xcf/0x270 kernel/sched/core.c:5157 io_uring_cancel_files fs/io_uring.c:8912 [inline] io_uring_cancel_task_requests+0xe70/0x11a0 fs/io_uring.c:8979 __io_uring_files_cancel+0x110/0x1b0 fs/io_uring.c:9067 io_uring_files_cancel include/linux/io_uring.h:51 [inline] do_exit+0x2fe/0x2ae0 kernel/exit.c:780 do_group_exit+0x125/0x310 kernel/exit.c:922 __do_sys_exit_group kernel/exit.c:933 [inline] __se_sys_exit_group kernel/exit.c:931 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Cc: stable@vger.kernel.org # 5.5+ Reported-by: syzbot+695b03d82fa8e4901b06@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: place ring SQ/CQ arrays under memcg memory limitsJens Axboe
Instead of imposing rlimit memlock limits for the rings themselves, ensure that we account them properly under memcg with __GFP_ACCOUNT. We retain rlimit memlock for registered buffers, this is just for the ring arrays themselves. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: enable kmemcg account for io_uring requestsJens Axboe
This puts io_uring under the memory cgroups accounting and limits for requests. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: enable req cache for IRQ driven IOJens Axboe
This is the last class of requests that cannot utilize the req alloc cache. Add a per-ctx req cache that is protected by the completion_lock, and refill our submit side cache when it gets over our batch count. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: fix possible deadlock in io_uring_pollHao Xu
Abaci reported follow issue: [ 30.615891] ====================================================== [ 30.616648] WARNING: possible circular locking dependency detected [ 30.617423] 5.11.0-rc3-next-20210115 #1 Not tainted [ 30.618035] ------------------------------------------------------ [ 30.618914] a.out/1128 is trying to acquire lock: [ 30.619520] ffff88810b063868 (&ep->mtx){+.+.}-{3:3}, at: __ep_eventpoll_poll+0x9f/0x220 [ 30.620505] [ 30.620505] but task is already holding lock: [ 30.621218] ffff88810e952be8 (&ctx->uring_lock){+.+.}-{3:3}, at: __x64_sys_io_uring_enter+0x3f0/0x5b0 [ 30.622349] [ 30.622349] which lock already depends on the new lock. [ 30.622349] [ 30.623289] [ 30.623289] the existing dependency chain (in reverse order) is: [ 30.624243] [ 30.624243] -> #1 (&ctx->uring_lock){+.+.}-{3:3}: [ 30.625263] lock_acquire+0x2c7/0x390 [ 30.625868] __mutex_lock+0xae/0x9f0 [ 30.626451] io_cqring_overflow_flush.part.95+0x6d/0x70 [ 30.627278] io_uring_poll+0xcb/0xd0 [ 30.627890] ep_item_poll.isra.14+0x4e/0x90 [ 30.628531] do_epoll_ctl+0xb7e/0x1120 [ 30.629122] __x64_sys_epoll_ctl+0x70/0xb0 [ 30.629770] do_syscall_64+0x2d/0x40 [ 30.630332] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 30.631187] [ 30.631187] -> #0 (&ep->mtx){+.+.}-{3:3}: [ 30.631985] check_prevs_add+0x226/0xb00 [ 30.632584] __lock_acquire+0x1237/0x13a0 [ 30.633207] lock_acquire+0x2c7/0x390 [ 30.633740] __mutex_lock+0xae/0x9f0 [ 30.634258] __ep_eventpoll_poll+0x9f/0x220 [ 30.634879] __io_arm_poll_handler+0xbf/0x220 [ 30.635462] io_issue_sqe+0xa6b/0x13e0 [ 30.635982] __io_queue_sqe+0x10b/0x550 [ 30.636648] io_queue_sqe+0x235/0x470 [ 30.637281] io_submit_sqes+0xcce/0xf10 [ 30.637839] __x64_sys_io_uring_enter+0x3fb/0x5b0 [ 30.638465] do_syscall_64+0x2d/0x40 [ 30.638999] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 30.639643] [ 30.639643] other info that might help us debug this: [ 30.639643] [ 30.640618] Possible unsafe locking scenario: [ 30.640618] [ 30.641402] CPU0 CPU1 [ 30.641938] ---- ---- [ 30.642664] lock(&ctx->uring_lock); [ 30.643425] lock(&ep->mtx); [ 30.644498] lock(&ctx->uring_lock); [ 30.645668] lock(&ep->mtx); [ 30.646321] [ 30.646321] *** DEADLOCK *** [ 30.646321] [ 30.647642] 1 lock held by a.out/1128: [ 30.648424] #0: ffff88810e952be8 (&ctx->uring_lock){+.+.}-{3:3}, at: __x64_sys_io_uring_enter+0x3f0/0x5b0 [ 30.649954] [ 30.649954] stack backtrace: [ 30.650592] CPU: 1 PID: 1128 Comm: a.out Not tainted 5.11.0-rc3-next-20210115 #1 [ 30.651554] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [ 30.652290] Call Trace: [ 30.652688] dump_stack+0xac/0xe3 [ 30.653164] check_noncircular+0x11e/0x130 [ 30.653747] ? check_prevs_add+0x226/0xb00 [ 30.654303] check_prevs_add+0x226/0xb00 [ 30.654845] ? add_lock_to_list.constprop.49+0xac/0x1d0 [ 30.655564] __lock_acquire+0x1237/0x13a0 [ 30.656262] lock_acquire+0x2c7/0x390 [ 30.656788] ? __ep_eventpoll_poll+0x9f/0x220 [ 30.657379] ? __io_queue_proc.isra.88+0x180/0x180 [ 30.658014] __mutex_lock+0xae/0x9f0 [ 30.658524] ? __ep_eventpoll_poll+0x9f/0x220 [ 30.659112] ? mark_held_locks+0x5a/0x80 [ 30.659648] ? __ep_eventpoll_poll+0x9f/0x220 [ 30.660229] ? _raw_spin_unlock_irqrestore+0x2d/0x40 [ 30.660885] ? trace_hardirqs_on+0x46/0x110 [ 30.661471] ? __io_queue_proc.isra.88+0x180/0x180 [ 30.662102] ? __ep_eventpoll_poll+0x9f/0x220 [ 30.662696] __ep_eventpoll_poll+0x9f/0x220 [ 30.663273] ? __ep_eventpoll_poll+0x220/0x220 [ 30.663875] __io_arm_poll_handler+0xbf/0x220 [ 30.664463] io_issue_sqe+0xa6b/0x13e0 [ 30.664984] ? __lock_acquire+0x782/0x13a0 [ 30.665544] ? __io_queue_proc.isra.88+0x180/0x180 [ 30.666170] ? __io_queue_sqe+0x10b/0x550 [ 30.666725] __io_queue_sqe+0x10b/0x550 [ 30.667252] ? __fget_files+0x131/0x260 [ 30.667791] ? io_req_prep+0xd8/0x1090 [ 30.668316] ? io_queue_sqe+0x235/0x470 [ 30.668868] io_queue_sqe+0x235/0x470 [ 30.669398] io_submit_sqes+0xcce/0xf10 [ 30.669931] ? xa_load+0xe4/0x1c0 [ 30.670425] __x64_sys_io_uring_enter+0x3fb/0x5b0 [ 30.671051] ? lockdep_hardirqs_on_prepare+0xde/0x180 [ 30.671719] ? syscall_enter_from_user_mode+0x2b/0x80 [ 30.672380] do_syscall_64+0x2d/0x40 [ 30.672901] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 30.673503] RIP: 0033:0x7fd89c813239 [ 30.673962] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 3d 01 f0 ff ff 73 01 c3 48 8b 0d 27 ec 2c 00 f7 d8 64 89 01 48 [ 30.675920] RSP: 002b:00007ffc65a7c628 EFLAGS: 00000217 ORIG_RAX: 00000000000001aa [ 30.676791] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd89c813239 [ 30.677594] RDX: 0000000000000000 RSI: 0000000000000014 RDI: 0000000000000003 [ 30.678678] RBP: 00007ffc65a7c720 R08: 0000000000000000 R09: 0000000003000000 [ 30.679492] R10: 0000000000000000 R11: 0000000000000217 R12: 0000000000400ff0 [ 30.680282] R13: 00007ffc65a7c840 R14: 0000000000000000 R15: 0000000000000000 This might happen if we do epoll_wait on a uring fd while reading/writing the former epoll fd in a sqe in the former uring instance. So let's don't flush cqring overflow list, just do a simple check. Reported-by: Abaci <abaci@linux.alibaba.com> Fixes: 6c503150ae33 ("io_uring: patch up IOPOLL overflow_flush sync") Signed-off-by: Hao Xu <haoxu@linux.alibaba.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: defer flushing cached reqsPavel Begunkov
Awhile there are requests in the allocation cache -- use them, only if those ended go for the stashed memory in comp.free_list. As list manipulation are generally heavy and are not good for caches, flush them all or as much as can in one go. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> [axboe: return success/failure from io_flush_cached_reqs()] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: take comp_state from ctxPavel Begunkov
__io_queue_sqe() is always called with a non-NULL comp_state, which is taken directly from context. Don't pass it around but infer from ctx. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: enable req cache for task_work itemsJens Axboe
task_work is run without utilizing the req alloc cache, so any deferred items don't get to take advantage of either the alloc or free side of it. With task_work now being wrapped by io_uring, we can use the ctx completion state to both use the req cache and the completion flush batching. With this, the only request type that cannot take advantage of the req cache is IRQ driven IO for regular files / block devices. Anything else, including IOPOLL polled IO to those same tyes, will take advantage of it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: provide FIFO ordering for task_workJens Axboe
task_work is a LIFO list, due to how it's implemented as a lockless list. For long chains of task_work, this can be problematic as the first entry added is the last one processed. Similarly, we'd waste a lot of CPU cycles reversing this list. Wrap the task_work so we have a single task_work entry per task per ctx, and use that to run it in the right order. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: use persistent request cacheJens Axboe
Now that we have the submit_state in the ring itself, we can have io_kiocb allocations that are persistent across invocations. This reduces the time spent doing slab allocations and frees. [sil: rebased] Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: feed reqs back into alloc cachePavel Begunkov
Make io_req_free_batch(), which is used for inline executed requests and IOPOLL, to return requests back into the allocation cache, so avoid most of kmalloc()/kfree() for those cases. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: persistent req cachePavel Begunkov
Don't free batch-allocated requests across syscalls. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: count ctx refs separately from reqsPavel Begunkov
Currently batch free handles request memory freeing and ctx ref putting together. Separate them and use different counters, that will be needed for reusing reqs memory. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: remove fallback_reqPavel Begunkov
Remove fallback_req for now, it gets in the way of other changes. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: submit-completion free batchingPavel Begunkov
io_submit_flush_completions() does completion batching, but may also use free batching as iopoll does. The main beneficiaries should be buffered reads/writes and send/recv. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: replace list with array for compl batchPavel Begunkov
Reincarnation of an old patch that replaces a list in struct io_compl_batch with an array. It's needed to avoid hooking requests via their compl.list, because it won't be always available in the future. It's also nice to split io_submit_flush_completions() to avoid free under locks and remove unlock/lock with a long comment describing when it can be done. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: don't reinit submit state every timePavel Begunkov
As now submit_state is retained across syscalls, we can save ourself from initialising it from ground up for each io_submit_sqes(). Set some fields during ctx allocation, and just keep them always consistent. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> [axboe: remove unnecessary zeroing of ctx members] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: remove ctx from comp_statePavel Begunkov
completion state is closely bound to ctx, we don't need to store ctx inside as we always have it around to pass to flush. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-02-10io_uring: don't keep submit_state on stackPavel Begunkov
struct io_submit_state is quite big (168 bytes) and going to grow. It's better to not keep it on stack as it is now. Move it to context, it's always protected by uring_lock, so it's fine to have only one instance of it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>