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2021-09-11Merge tag 'io_uring-5.15-2021-09-11' of git://git.kernel.dk/linux-blockLinus Torvalds1-2/+14
Pull io_uring fixes from Jens Axboe: - Fix an off-by-one in a BUILD_BUG_ON() check. Not a real issue right now as we have plenty of flags left, but could become one. (Hao) - Fix lockdep issue introduced in this merge window (me) - Fix a few issues with the worker creation (me, Pavel, Qiang) - Fix regression with wq_has_sleeper() for IOPOLL (Pavel) - Timeout link error propagation fix (Pavel) * tag 'io_uring-5.15-2021-09-11' of git://git.kernel.dk/linux-block: io_uring: fix off-by-one in BUILD_BUG_ON check of __REQ_F_LAST_BIT io_uring: fail links of cancelled timeouts io-wq: fix memory leak in create_io_worker() io-wq: fix silly logic error in io_task_work_match() io_uring: drop ctx->uring_lock before acquiring sqd->lock io_uring: fix missing mb() before waitqueue_active io-wq: fix cancellation on create-worker failure
2021-09-10io_uring: fix off-by-one in BUILD_BUG_ON check of __REQ_F_LAST_BITHao Xu1-1/+1
Build check of __REQ_F_LAST_BIT should be larger than, not equal or larger than. It's perfectly valid to have __REQ_F_LAST_BIT be 32, as that means that the last valid bit is 31 which does fit in the type. Signed-off-by: Hao Xu <haoxu@linux.alibaba.com> Link: https://lore.kernel.org/r/20210907032243.114190-1-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-09Merge branch 'work.iov_iter' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull iov_iter fixes from Al Viro: "Fixes for io-uring handling of iov_iter reexpands" * 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: io_uring: reexpand under-reexpanded iters iov_iter: track truncated size
2021-09-09io_uring: fail links of cancelled timeoutsPavel Begunkov1-0/+2
When we cancel a timeout we should mark it with REQ_F_FAIL, so linked requests are cancelled as well, but not queued for further execution. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/fff625b44eeced3a5cae79f60e6acf3fbdf8f990.1631192135.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-08io_uring: drop ctx->uring_lock before acquiring sqd->lockJens Axboe1-0/+7
The SQPOLL thread dictates the lock order, and we hold the ctx->uring_lock for all the registration opcodes. We also hold a ref to the ctx, and we do drop the lock for other reasons to quiesce, so it's fine to drop the ctx lock temporarily to grab the sqd->lock. This fixes the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.14.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/25433 is trying to acquire lock: ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: io_register_iowq_max_workers fs/io_uring.c:10551 [inline] ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: __io_uring_register fs/io_uring.c:10757 [inline] ffff888023426870 (&sqd->lock){+.+.}-{3:3}, at: __do_sys_io_uring_register+0x10aa/0x2e70 fs/io_uring.c:10792 but task is already holding lock: ffff8880885b40a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_register+0x2e1/0x2e70 fs/io_uring.c:10791 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ctx->uring_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:596 [inline] __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729 __io_sq_thread fs/io_uring.c:7291 [inline] io_sq_thread+0x65a/0x1370 fs/io_uring.c:7368 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #0 (&sqd->lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __mutex_lock_common kernel/locking/mutex.c:596 [inline] __mutex_lock+0x131/0x12f0 kernel/locking/mutex.c:729 io_register_iowq_max_workers fs/io_uring.c:10551 [inline] __io_uring_register fs/io_uring.c:10757 [inline] __do_sys_io_uring_register+0x10aa/0x2e70 fs/io_uring.c:10792 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ctx->uring_lock); lock(&sqd->lock); lock(&ctx->uring_lock); lock(&sqd->lock); *** DEADLOCK *** Fixes: 2e480058ddc2 ("io-wq: provide a way to limit max number of workers") Reported-by: syzbot+97fa56483f69d677969f@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-08io_uring: fix missing mb() before waitqueue_activePavel Begunkov1-1/+4
In case of !SQPOLL, io_cqring_ev_posted_iopoll() doesn't provide a memory barrier required by waitqueue_active(&ctx->poll_wait). There is a wq_has_sleeper(), which does smb_mb() inside, but it's called only for SQPOLL. Fixes: 5fd4617840596 ("io_uring: be smarter about waking multiple CQ ring waiters") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2982e53bcea2274006ed435ee2a77197107d8a29.1631130542.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-06Merge tag 'for-5.15/io_uring-2021-09-04' of git://git.kernel.dk/linux-blockLinus Torvalds1-10/+66
Pull io_uring fixes from Jens Axboe: "As sometimes happens, two reports came in around the merge window open that led to some fixes. Hence this one is a bit bigger than usual followup fixes, but most of it will be going towards stable, outside of the fixes that are addressing regressions from this merge window. In detail: - postgres is a heavy user of signals between tasks, and if we're unlucky this can interfere with io-wq worker creation. Make sure we're resilient against unrelated signal handling. This set of changes also includes hardening against allocation failures, which could previously had led to stalls. - Some use cases that end up having a mix of bounded and unbounded work would have starvation issues related to that. Split the pending work lists to handle that better. - Completion trace int -> unsigned -> long fix - Fix issue with REGISTER_IOWQ_MAX_WORKERS and SQPOLL - Fix regression with hash wait lock in this merge window - Fix retry issued on block devices (Ming) - Fix regression with links in this merge window (Pavel) - Fix race with multi-shot poll and completions (Xiaoguang) - Ensure regular file IO doesn't inadvertently skip completion batching (Pavel) - Ensure submissions are flushed after running task_work (Pavel)" * tag 'for-5.15/io_uring-2021-09-04' of git://git.kernel.dk/linux-block: io_uring: io_uring_complete() trace should take an integer io_uring: fix possible poll event lost in multi shot mode io_uring: prolong tctx_task_work() with flushing io_uring: don't disable kiocb_done() CQE batching io_uring: ensure IORING_REGISTER_IOWQ_MAX_WORKERS works with SQPOLL io-wq: make worker creation resilient against signals io-wq: get rid of FIXED worker flag io-wq: only exit on fatal signals io-wq: split bounded and unbounded work into separate lists io-wq: fix queue stalling race io_uring: don't submit half-prepared drain request io_uring: fix queueing half-created requests io-wq: ensure that hash wait lock is IRQ disabling io_uring: retry in case of short read on block device io_uring: IORING_OP_WRITE needs hash_reg_file set io-wq: fix race between adding work and activating a free worker
2021-09-03io_uring: reexpand under-reexpanded itersPavel Begunkov1-0/+2
[ 74.211232] BUG: KASAN: stack-out-of-bounds in iov_iter_revert+0x809/0x900 [ 74.212778] Read of size 8 at addr ffff888025dc78b8 by task syz-executor.0/828 [ 74.214756] CPU: 0 PID: 828 Comm: syz-executor.0 Not tainted 5.14.0-rc3-next-20210730 #1 [ 74.216525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 74.219033] Call Trace: [ 74.219683] dump_stack_lvl+0x8b/0xb3 [ 74.220706] print_address_description.constprop.0+0x1f/0x140 [ 74.224226] kasan_report.cold+0x7f/0x11b [ 74.226085] iov_iter_revert+0x809/0x900 [ 74.227960] io_write+0x57d/0xe40 [ 74.232647] io_issue_sqe+0x4da/0x6a80 [ 74.242578] __io_queue_sqe+0x1ac/0xe60 [ 74.245358] io_submit_sqes+0x3f6e/0x76a0 [ 74.248207] __do_sys_io_uring_enter+0x90c/0x1a20 [ 74.257167] do_syscall_64+0x3b/0x90 [ 74.257984] entry_SYSCALL_64_after_hwframe+0x44/0xae old_size = iov_iter_count(); ... iov_iter_revert(old_size - iov_iter_count()); If iov_iter_revert() is done base on the initial size as above, and the iter is truncated and not reexpanded in the middle, it miscalculates borders causing problems. This trace is due to no one reexpanding after generic_write_checks(). Now iters store how many bytes has been truncated, so reexpand them to the initial state right before reverting. Cc: stable@vger.kernel.org Reported-by: Palash Oswal <oswalpalash@gmail.com> Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Reported-and-tested-by: syzbot+9671693590ef5aad8953@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-09-03io_uring: fix possible poll event lost in multi shot modeXiaoguang Wang1-3/+13
IIUC, IORING_POLL_ADD_MULTI is similar to epoll's edge-triggered mode, that means once one pure poll request returns one event(cqe), we'll need to read or write continually until EAGAIN is returned, then I think there is a possible poll event lost race in multi shot mode: t1 poll request add | | t2 | | t3 event happens | | t4 task work add | | t5 | task work run | t6 | commit one cqe | t7 | | user app handles cqe t8 | new event happen | t9 | add back to waitqueue | t10 | After t6 but before t9, if new event happens, there'll be no wakeup operation, and if user app has picked up this cqe in t7, read or write until EAGAIN is returned. In t8, new event happens and will be lost, though this race window maybe small. To fix this possible race, add poll request back to waitqueue before committing cqe. Fixes: 88e41cf928a6 ("io_uring: add multishot mode for IORING_OP_POLL_ADD") Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Link: https://lore.kernel.org/r/20210903142436.5767-1-xiaoguang.wang@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-03io_uring: prolong tctx_task_work() with flushingPavel Begunkov1-0/+3
io_submit_flush_completions() may enqueue linked requests for task_work execution, so don't leave tctx_task_work() right after the tw list is exhausted, but try to flush and then retry. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/0755d4c2c36301447c63bdd4146c10477cea4249.1630539342.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-03io_uring: don't disable kiocb_done() CQE batchingPavel Begunkov1-1/+1
Not passing issue_flags from kiocb_done() into __io_complete_rw() means that completion batching for this case is disabled, e.g. for most of buffered reads. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b2689462835c3ee28a5999ef4f9a581e24be04a2.1630539342.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-03io_uring: ensure IORING_REGISTER_IOWQ_MAX_WORKERS works with SQPOLLJens Axboe1-4/+24
SQPOLL has a different thread doing submissions, we need to check for that and use the right task context when updating the worker values. Just hold the sqd->lock across the operation, this ensures that the thread cannot go away while we poke at ->io_uring. Link: https://github.com/axboe/liburing/issues/420 Fixes: 2e480058ddc2 ("io-wq: provide a way to limit max number of workers") Reported-by: Johannes Lundberg <johalun0@gmail.com> Tested-by: Johannes Lundberg <johalun0@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-31io_uring: don't submit half-prepared drain requestPavel Begunkov1-0/+5
[ 3784.910888] BUG: kernel NULL pointer dereference, address: 0000000000000020 [ 3784.910904] RIP: 0010:__io_file_supports_nowait+0x5/0xc0 [ 3784.910926] Call Trace: [ 3784.910928] ? io_read+0x17c/0x480 [ 3784.910945] io_issue_sqe+0xcb/0x1840 [ 3784.910953] __io_queue_sqe+0x44/0x300 [ 3784.910959] io_req_task_submit+0x27/0x70 [ 3784.910962] tctx_task_work+0xeb/0x1d0 [ 3784.910966] task_work_run+0x61/0xa0 [ 3784.910968] io_run_task_work_sig+0x53/0xa0 [ 3784.910975] __x64_sys_io_uring_enter+0x22/0x30 [ 3784.910977] do_syscall_64+0x3d/0x90 [ 3784.910981] entry_SYSCALL_64_after_hwframe+0x44/0xae io_drain_req() goes before checks for REQ_F_FAIL, which protect us from submitting under-prepared request (e.g. failed in io_init_req(). Fail such drained requests as well. Fixes: a8295b982c46d ("io_uring: fix failed linkchain code logic") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/e411eb9924d47a131b1e200b26b675df0c2b7627.1630415423.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-31io_uring: fix queueing half-created requestsPavel Begunkov1-1/+12
[ 27.259845] general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN PTI [ 27.261043] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] [ 27.263730] RIP: 0010:sock_from_file+0x20/0x90 [ 27.272444] Call Trace: [ 27.272736] io_sendmsg+0x98/0x600 [ 27.279216] io_issue_sqe+0x498/0x68d0 [ 27.281142] __io_queue_sqe+0xab/0xb50 [ 27.285830] io_req_task_submit+0xbf/0x1b0 [ 27.286306] tctx_task_work+0x178/0xad0 [ 27.288211] task_work_run+0xe2/0x190 [ 27.288571] exit_to_user_mode_prepare+0x1a1/0x1b0 [ 27.289041] syscall_exit_to_user_mode+0x19/0x50 [ 27.289521] do_syscall_64+0x48/0x90 [ 27.289871] entry_SYSCALL_64_after_hwframe+0x44/0xae io_req_complete_failed() -> io_req_complete_post() -> io_req_task_queue() still would try to enqueue hard linked request, which can be half prepared (e.g. failed init), so we can't allow that to happen. Fixes: a8295b982c46d ("io_uring: fix failed linkchain code logic") Reported-by: syzbot+f9704d1878e290eddf73@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/70b513848c1000f88bd75965504649c6bb1415c0.1630415423.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-31io_uring: retry in case of short read on block deviceMing Lei1-1/+7
In case of buffered reading from block device, when short read happens, we should retry to read more, otherwise the IO will be completed partially, for example, the following fio expects to read 2MB, but it can only read 1M or less bytes: fio --name=onessd --filename=/dev/nvme0n1 --filesize=2M \ --rw=randread --bs=2M --direct=0 --overwrite=0 --numjobs=1 \ --iodepth=1 --time_based=0 --runtime=2 --ioengine=io_uring \ --registerfiles --fixedbufs --gtod_reduce=1 --group_reporting Fix the issue by allowing short read retry for block device, which sets FMODE_BUF_RASYNC really. Fixes: 9a173346bd9e ("io_uring: fix short read retries for non-reg files") Cc: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20210821150751.1290434-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-31io_uring: IORING_OP_WRITE needs hash_reg_file setJens Axboe1-0/+1
During some testing, it became evident that using IORING_OP_WRITE doesn't hash buffered writes like the other writes commands do. That's simply an oversight, and can cause performance regressions when doing buffered writes with this command. Correct that and add the flag, so that buffered writes are correctly hashed when using the non-iovec based write command. Cc: stable@vger.kernel.org Fixes: 3a6820f2bb8a ("io_uring: add non-vectored read/write commands") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-30Merge tag 'for-5.15/io_uring-vfs-2021-08-30' of git://git.kernel.dk/linux-blockLinus Torvalds1-0/+198
Pull io_uring mkdirat/symlinkat/linkat support from Jens Axboe: "This adds io_uring support for mkdirat, symlinkat, and linkat" * tag 'for-5.15/io_uring-vfs-2021-08-30' of git://git.kernel.dk/linux-block: io_uring: add support for IORING_OP_LINKAT io_uring: add support for IORING_OP_SYMLINKAT io_uring: add support for IORING_OP_MKDIRAT namei: update do_*() helpers to return ints namei: make do_linkat() take struct filename namei: add getname_uflags() namei: make do_symlinkat() take struct filename namei: make do_mknodat() take struct filename namei: make do_mkdirat() take struct filename namei: change filename_parentat() calling conventions namei: ignore ERR/NULL names in putname()
2021-08-30Merge tag 'io_uring-bio-cache.5-2021-08-30' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+1
Pull support for struct bio recycling from Jens Axboe: "This adds bio recycling support for polled IO, allowing quick reuse of a bio for high IOPS scenarios via a percpu bio_set list. It's good for almost a 10% improvement in performance, bumping our per-core IO limit from ~3.2M IOPS to ~3.5M IOPS" * tag 'io_uring-bio-cache.5-2021-08-30' of git://git.kernel.dk/linux-block: bio: improve kerneldoc documentation for bio_alloc_kiocb() block: provide bio_clear_hipri() helper block: use the percpu bio cache in __blkdev_direct_IO io_uring: enable use of bio alloc cache block: clear BIO_PERCPU_CACHE flag if polling isn't supported bio: add allocation cache abstraction fs: add kiocb alloc cache flag bio: optimize initialization of a bio
2021-08-29io_uring: allow updating linked timeoutsPavel Begunkov1-4/+40
We allow updating normal timeouts, add support for adjusting timings of linked timeouts as well. Reported-by: Victor Stewart <v@nametag.social> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-29io_uring: keep ltimeouts in a listPavel Begunkov1-0/+7
A preparation patch. Keep all queued linked timeout in a list, so they may be found and updated. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-29io_uring: support CLOCK_BOOTTIME/REALTIME for timeoutsJens Axboe1-3/+24
Certain use cases want to use CLOCK_BOOTTIME or CLOCK_REALTIME rather than CLOCK_MONOTONIC, instead of the default CLOCK_MONOTONIC. Add an IORING_TIMEOUT_BOOTTIME and IORING_TIMEOUT_REALTIME flag that allows timeouts and linked timeouts to use the selected clock source. Only one clock source may be selected, and we -EINVAL the request if more than one is given. If neither BOOTIME nor REALTIME are selected, the previous default of MONOTONIC is used. Link: https://github.com/axboe/liburing/issues/369 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-29io-wq: provide a way to limit max number of workersJens Axboe1-0/+32
io-wq divides work into two categories: 1) Work that completes in a bounded time, like reading from a regular file or a block device. This type of work is limited based on the size of the SQ ring. 2) Work that may never complete, we call this unbounded work. The amount of workers here is just limited by RLIMIT_NPROC. For various uses cases, it's handy to have the kernel limit the maximum amount of pending workers for both categories. Provide a way to do with with a new IORING_REGISTER_IOWQ_MAX_WORKERS operation. IORING_REGISTER_IOWQ_MAX_WORKERS takes an array of two integers and sets the max worker count to what is being passed in for each category. The old values are returned into that same array. If 0 is being passed in for either category, it simply returns the current value. The value is capped at RLIMIT_NPROC. This actually isn't that important as it's more of a hint, if we're exceeding the value then our attempt to fork a new worker will fail. This happens naturally already if more than one node is in the system, as these values are per-node internally for io-wq. Reported-by: Johannes Lundberg <johalun0@gmail.com> Link: https://github.com/axboe/liburing/issues/420 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-27io_uring: add build check for buf_index overflowsPavel Begunkov1-0/+4
req->buf_index is u16 and so we rely on registered buffers indexes fitting into it. Add a build check, so when the upper limit for the number of buffers is lifted we get a compliation fail but not lurking problems. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/787e8e1a17cea51ca6301426b1c4c4887b8bd676.1629920396.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-27io_uring: clarify io_req_task_cancel() lockingPavel Begunkov1-2/+1
It's too easy to forget and misjudge about synchronisation in io_req_task_cancel(), add a comment clarifying it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/71099083835f983a1fd73d5a3da6391924da8300.1629920396.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-27io_uring: add task-refs-get helperPavel Begunkov1-11/+19
As we have a more complicated task referencing, which apart from normal task references includes taking tctx->inflight and caching all that, it would be a good idea to have all that isolated in helpers. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d9114d037f1c195897aa13f38a496078eca2afdb.1630023531.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-27io_uring: fix failed linkchain code logicHao Xu1-14/+47
Given a linkchain like this: req0(link_flag)-->req1(link_flag)-->...-->reqn(no link_flag) There is a problem: - if some intermediate linked req like req1 's submittion fails, reqs after it won't be cancelled. - sqpoll disabled: maybe it's ok since users can get the error info of req1 and stop submitting the following sqes. - sqpoll enabled: definitely a problem, the following sqes will be submitted in the next round. The solution is to refactor the code logic to: - if a linked req's submittion fails, just mark it and the head(if it exists) as REQ_F_FAIL. Leverage req->result to indicate whether it is failed or cancelled. - submit or fail the whole chain when we come to the end of it. Signed-off-by: Hao Xu <haoxu@linux.alibaba.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20210827094609.36052-3-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-27io_uring: remove redundant req_set_fail()Hao Xu1-1/+0
req_set_fail() in io_submit_sqe() is redundant, remove it. Signed-off-by: Hao Xu <haoxu@linux.alibaba.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20210827094609.36052-2-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25io_uring: don't free request to slabHao Xu1-1/+1
It's not necessary to free the request back to slab when we fail to get sqe, just move it to state->free_list. Signed-off-by: Hao Xu <haoxu@linux.alibaba.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20210825175856.194299-1-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25io_uring: accept directly into fixed file tablePavel Begunkov1-6/+18
As done with open opcodes, allow accept to skip installing fd into processes' file tables and put it directly into io_uring's fixed file table. Same restrictions and design as for open. Suggested-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/6d16163f376fac7ac26a656de6b42199143e9721.1629888991.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25io_uring: hand code io_accept() fd installingPavel Begunkov1-7/+20
Make io_accept() to handle file descriptor allocations and installation. A preparation patch for bypassing file tables. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/5b73d204caa0ce979ccb98136695b60f52a3d98c.1629888991.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-25io_uring: openat directly into fixed fd tablePavel Begunkov1-8/+66
Instead of opening a file into a process's file table as usual and then registering the fd within io_uring, some users may want to skip the first step and place it directly into io_uring's fixed file table. This patch adds such a capability for IORING_OP_OPENAT and IORING_OP_OPENAT2. The behaviour is controlled by setting sqe->file_index, where 0 implies the old behaviour using normal file tables. If non-zero value is specified, then it will behave as described and place the file into a fixed file slot sqe->file_index - 1. A file table should be already created, the slot should be valid and empty, otherwise the operation will fail. Keep the error codes consistent with IORING_OP_FILES_UPDATE, ENXIO and EINVAL on inappropriate fixed tables, and return EBADF on collision with already registered file. Note: IOSQE_FIXED_FILE can't be used to switch between modes, because accept takes a file, and it already uses the flag with a different meaning. Suggested-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/e9b33d1163286f51ea707f87d95bd596dada1e65.1629888991.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: add support for IORING_OP_LINKATDmitry Kadashev1-0/+71
IORING_OP_LINKAT behaves like linkat(2) and takes the same flags and arguments. In some internal places 'hardlink' is used instead of 'link' to avoid confusion with the SQE links. Name 'link' conflicts with the existing 'link' member of io_kiocb. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Suggested-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/ Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20210708063447.3556403-12-dkadashev@gmail.com [axboe: add splice_fd_in check] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: add support for IORING_OP_SYMLINKATDmitry Kadashev1-0/+67
IORING_OP_SYMLINKAT behaves like symlinkat(2) and takes the same flags and arguments. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Suggested-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/ Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20210708063447.3556403-11-dkadashev@gmail.com [axboe: add splice_fd_in check] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: enable use of bio alloc cacheJens Axboe1-1/+1
Mark polled IO as being safe for dipping into the bio allocation cache, in case the targeted bio_set has it enabled. This brings an IOPOLL gen2 Optane QD=128 workload from ~3.2M IOPS to ~3.5M IOPS. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: fix io_try_cancel_userdata race for iowqPavel Begunkov1-2/+3
WARNING: CPU: 1 PID: 5870 at fs/io_uring.c:5975 io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975 CPU: 0 PID: 5870 Comm: iou-wrk-5860 Not tainted 5.14.0-rc6-next-20210820-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975 Call Trace: io_async_cancel fs/io_uring.c:6014 [inline] io_issue_sqe+0x22d5/0x65a0 fs/io_uring.c:6407 io_wq_submit_work+0x1dc/0x300 fs/io_uring.c:6511 io_worker_handle_work+0xa45/0x1840 fs/io-wq.c:533 io_wqe_worker+0x2cc/0xbb0 fs/io-wq.c:582 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 io_try_cancel_userdata() can be called from io_async_cancel() executing in the io-wq context, so the warning fires, which is there to alert anyone accessing task->io_uring->io_wq in a racy way. However, io_wq_put_and_exit() always first waits for all threads to complete, so the only detail left is to zero tctx->io_wq after the context is removed. note: one little assumption is that when IO_WQ_WORK_CANCEL, the executor won't touch ->io_wq, because io_wq_destroy() might cancel left pending requests in such a way. Cc: stable@vger.kernel.org Reported-by: syzbot+b0c9d1588ae92866515f@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/dfdd37a80cfa9ffd3e59538929c99cdd55d8699e.1629721757.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: add support for IORING_OP_MKDIRATDmitry Kadashev1-0/+60
IORING_OP_MKDIRAT behaves like mkdirat(2) and takes the same flags and arguments. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/20210708063447.3556403-10-dkadashev@gmail.com [axboe: add splice_fd_in check] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: IRQ rw completion batchingPavel Begunkov1-1/+16
Employ inline completion logic for read/write completions done via io_req_task_complete(). If ->uring_lock is contended, just do normal request completion, but if not, make tctx_task_work() to grab the lock and do batched inline completions in io_req_task_complete(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/94589c3ce69eaed86a21bb1ec696407a54fab1aa.1629286357.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: batch task work lockingPavel Begunkov1-31/+49
Many task_work handlers either grab ->uring_lock, or may benefit from having it. Move locking logic out of individual handlers to a lazy approach controlled by tctx_task_work(), so we don't keep doing tons of mutex lock/unlock. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d6a34e147f2507a2f3e2fa1e38a9c541dcad3929.1629286357.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: flush completions for fallbacksPavel Begunkov1-0/+5
io_fallback_req_func() doesn't expect anyone creating inline completions, and no one currently does that. Teach the function to flush completions preparing for further changes. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8b941516921f72e1a64d58932d671736892d7fff.1629286357.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: add ->splice_fd_in checksPavel Begunkov1-22/+30
->splice_fd_in is used only by splice/tee, but no other request checks it for validity. Add the check for most of request types excluding reads/writes/sends/recvs, we don't want overhead for them and can leave them be as is until the field is actually used. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/f44bc2acd6777d932de3d71a5692235b5b2b7397.1629451684.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: add clarifying comment for io_cqring_ev_posted()Jens Axboe1-0/+7
We've previously had an issue where overflow flush unconditionally calls io_cqring_ev_posted() even if it didn't flush any events to the ring, causing wake and eventfd increment where no new events are available. Some applications don't like that, see commit b18032bb0a88 for details. This came up in discussion for another patch recently, hence add a comment detailing what the relationship between calling the events posted helper and CQ ring entries is. Link: https://lore.kernel.org/io-uring/77a44fce-c831-16a6-8e80-9aee77f496a2@kernel.dk/ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: place fixed tables under memcg limitsPavel Begunkov1-3/+4
Fixed tables may be large enough, place all of them together with allocated tags under memcg limits. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b3ac9f5da9821bb59837b5fe25e8ef4be982218c.1629451684.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: limit fixed table size by RLIMIT_NOFILEPavel Begunkov1-0/+2
Limit the number of files in io_uring fixed tables by RLIMIT_NOFILE, that's the first and the simpliest restriction that we should impose. Cc: stable@vger.kernel.org Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b2756c340aed7d6c0b302c26dab50c6c5907f4ce.1629451684.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: fix lack of protection for compl_nrHao Xu1-1/+2
coml_nr in ctx_flush_and_put() is not protected by uring_lock, this may cause problems when accessing in parallel: say coml_nr > 0 ctx_flush_and put other context if (compl_nr) get mutex coml_nr > 0 do flush coml_nr = 0 release mutex get mutex do flush (*) release mutex in (*) place, we call io_cqring_ev_posted() and users likely get no events there. To avoid spurious events, re-check the value when under the lock. Fixes: 2c32395d8111 ("io_uring: fix __tctx_task_work() ctx race") Signed-off-by: Hao Xu <haoxu@linux.alibaba.com> Link: https://lore.kernel.org/r/20210820221954.61815-1-haoxu@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: Add register support for non-4k PAGE_SIZEwangyangbo1-2/+2
Now allocated rsrc table uses PAGE_SIZE as the size of 2nd-level, and accessing this table relies on each level index from fixed TABLE_SHIFT (12 - 3) in 4k page case. In order to correctly work in non-4k page, define TABLE_SHIFT as non-fixed (PAGE_SHIFT - shift of data) for 2nd-level table entry number. Signed-off-by: wangyangbo <wangyangbo@uniontech.com> Link: https://lore.kernel.org/r/20210819055657.27327-1-wangyangbo@uniontech.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: extend task put optimisationsPavel Begunkov1-7/+9
Now with IRQ completions done via IRQ, almost all requests freeing are done from the context of submitter task, so it makes sense to extend task_put optimisation from io_req_free_batch_finish() to cover all the cases including task_work by moving it into io_put_task(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/824a7cbd745ddeee4a0f3ff85c558a24fd005872.1629302453.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: add comments on why PF_EXITING checking is safeJens Axboe1-0/+2
We have two checks of task->flags & PF_EXITING left: 1) In io_req_task_submit(), which is called in task_work and hence always in the context of the original task. That means that req->task == current, and hence checking ->flags is totally fine. 2) In io_poll_rewait(), where we need to stop re-arming poll to prevent it interfering with cancelation. This is only run from task_work as well, and hence for this case too req->task == current. Add a comment to both spots detailing that. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: fix io_timeout_remove lockingPavel Begunkov1-4/+10
io_timeout_cancel() posts CQEs so needs ->completion_lock to be held, so grab it in io_timeout_remove(). Fixes: 48ecb6369f1f2 ("io_uring: run timeouts from task_work") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d6f03d653a4d7bf693ef6f39b6a426b6d97fd96f.1629280204.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: improve same wq pollingPavel Begunkov1-3/+5
Move earlier the check for whether __io_queue_proc() tries to poll already polled waitqueue, and do the same for the second poll entry, if any. Shouldn't really matter, but at least it would have a more predictable behaviour. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8cb428cfe8ade0fd055859fabb878db8777d4c2f.1629228203.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23io_uring: reuse io_req_complete_post()Pavel Begunkov1-37/+11
We have io_req_complete_post() to post a CQE and put the request. It takes care of all synchronisation and is more concise and efficent, so replace all hancoded occurrences of "lock; post CQE; unlock; + put_req()" with io_req_complete_post(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2c83463458a613f9d870e5147eb134da2aa70779.1629228203.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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