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* io-wq: kill now unused io_wq_cancel_all()Jens Axboe2020-12-201-29/+1
| | | | | | | io_uring no longer issues full cancelations on the io-wq, so remove any remnants of this code and the IO_WQ_BIT_CANCEL flag. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: always batch cancel in *cancel_files()Pavel Begunkov2020-12-091-10/+0
| | | | | | | | | | | | Instead of iterating over each request and cancelling it individually in io_uring_cancel_files(), try to cancel all matching requests and use ->inflight_list only to check if there anything left. In many cases it should be faster, and we can reuse a lot of code from task cancellation. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: cancel request if it's asking for files and we don't have themJens Axboe2020-11-041-0/+4
| | | | | | | | This can't currently happen, but will be possible shortly. Handle missing files just like we do not being able to grab a needed mm, and mark the request as needing cancelation. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: re-set NUMA node affinities if CPUs come onlineJens Axboe2020-10-221-4/+56
| | | | | | | | | | | We correctly set io-wq NUMA node affinities when the io-wq context is setup, but if an entire node CPU set is offlined and then brought back online, the per node affinities are broken. Ensure that we set them again whenever a CPU comes online. This ensures that we always track the right node affinity. The usual cpuhp notifiers are used to drive it. Reported-by: Zhang Qiang <qiang.zhang@windriver.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: unify fsize with def->work_flagsJens Axboe2020-10-201-2/+6
| | | | | | | | | This one was missed in the earlier conversion, should be included like any of the other IO identity flags. Make sure we restore to RLIM_INIFITY when dropping the personality again. Fixes: 98447d65b4a7 ("io_uring: move io identity items into separate struct") Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: inherit audit loginuid and sessionidJens Axboe2020-10-171-0/+10
| | | | | | | | | | | Make sure the async io-wq workers inherit the loginuid and sessionid from the original task, and restore them to unset once we're done with the async work item. While at it, disable the ability for kernel threads to write to their own loginuid. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: move io identity items into separate structJens Axboe2020-10-171-16/+18
| | | | | | | | | | | io-wq contains a pointer to the identity, which we just hold in io_kiocb for now. This is in preparation for putting this outside io_kiocb. The only exception is struct files_struct, which we'll need different rules for to avoid a circular dependency. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: rely solely on work flags to determine personality.Jens Axboe2020-10-171-4/+0
| | | | | | | We solely rely on work->work_flags now, so use that for proper checking and clearing/dropping of various identity items. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: pass required context in as flagsJens Axboe2020-10-171-4/+6
| | | | | | | | | | We have a number of bits that decide what context to inherit. Set up io-wq flags for these instead. This is in preparation for always having the various members set, but not always needing them for all requests. No intended functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: assign NUMA node locality if appropriateJens Axboe2020-10-171-0/+1
| | | | | | | | | | There was an assumption that kthread_create_on_node() would properly set NUMA affinities in terms of CPUs allowed, but it doesn't. Make sure we do this when creating an io-wq context on NUMA. Cc: stable@vger.kernel.org Stefan Metzmacher <metze@samba.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: kill unused IO_WORKER_F_EXITINGJens Axboe2020-09-301-3/+2
| | | | | | This flag is no longer used, remove it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: fix use-after-free in io_wq_worker_runningHillf Danton2020-09-301-58/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The smart syzbot has found a reproducer for the following issue: ================================================================== BUG: KASAN: use-after-free in instrument_atomic_write include/linux/instrumented.h:71 [inline] BUG: KASAN: use-after-free in atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] BUG: KASAN: use-after-free in io_wqe_inc_running fs/io-wq.c:301 [inline] BUG: KASAN: use-after-free in io_wq_worker_running+0xde/0x110 fs/io-wq.c:613 Write of size 4 at addr ffff8882183db08c by task io_wqe_worker-0/7771 CPU: 0 PID: 7771 Comm: io_wqe_worker-0 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:186 [inline] check_memory_region+0x13d/0x180 mm/kasan/generic.c:192 instrument_atomic_write include/linux/instrumented.h:71 [inline] atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] io_wqe_inc_running fs/io-wq.c:301 [inline] io_wq_worker_running+0xde/0x110 fs/io-wq.c:613 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879 io_wqe_worker+0x517/0x10e0 fs/io-wq.c:580 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Allocated by task 7768: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 kmem_cache_alloc_node_trace+0x17b/0x3f0 mm/slab.c:3594 kmalloc_node include/linux/slab.h:572 [inline] kzalloc_node include/linux/slab.h:677 [inline] io_wq_create+0x57b/0xa10 fs/io-wq.c:1064 io_init_wq_offload fs/io_uring.c:7432 [inline] io_sq_offload_start fs/io_uring.c:7504 [inline] io_uring_create fs/io_uring.c:8625 [inline] io_uring_setup+0x1836/0x28e0 fs/io_uring.c:8694 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 21: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kfree+0x10e/0x2b0 mm/slab.c:3756 __io_wq_destroy fs/io-wq.c:1138 [inline] io_wq_destroy+0x2af/0x460 fs/io-wq.c:1146 io_finish_async fs/io_uring.c:6836 [inline] io_ring_ctx_free fs/io_uring.c:7870 [inline] io_ring_exit_work+0x1e4/0x6d0 fs/io_uring.c:7954 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 The buggy address belongs to the object at ffff8882183db000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 140 bytes inside of 1024-byte region [ffff8882183db000, ffff8882183db400) The buggy address belongs to the page: page:000000009bada22b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2183db flags: 0x57ffe0000000200(slab) raw: 057ffe0000000200 ffffea0008604c48 ffffea00086a8648 ffff8880aa040700 raw: 0000000000000000 ffff8882183db000 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8882183daf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8882183db000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8882183db080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8882183db100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8882183db180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== which is down to the comment below, /* all workers gone, wq exit can proceed */ if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs)) complete(&wqe->wq->done); because there might be multiple cases of wqe in a wq and we would wait for every worker in every wqe to go home before releasing wq's resources on destroying. To that end, rework wq's refcount by making it independent of the tracking of workers because after all they are two different things, and keeping it balanced when workers come and go. Note the manager kthread, like other workers, now holds a grab to wq during its lifetime. Finally to help destroy wq, check IO_WQ_BIT_EXIT upon creating worker and do nothing for exiting wq. Cc: stable@vger.kernel.org # v5.5+ Reported-by: syzbot+45fa0a195b941764e0f0@syzkaller.appspotmail.com Reported-by: syzbot+9af99580130003da82b1@syzkaller.appspotmail.com Cc: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Hillf Danton <hdanton@sina.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: add blkcg accounting to offloaded operationsDennis Zhou2020-09-301-0/+23
| | | | | | | | | | | | | | There are a few operations that are offloaded to the worker threads. In this case, we lose process context and end up in kthread context. This results in ios to be not accounted to the issuing cgroup and consequently end up as issued by root. Just like others, adopt the personality of the blkcg too when issuing via the workqueues. For the SQPOLL thread, it will live and attach in the inited cgroup's context. Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_wq: Make io_wqe::lock a raw_spinlock_tSebastian Andrzej Siewior2020-09-301-26/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During a context switch the scheduler invokes wq_worker_sleeping() with disabled preemption. Disabling preemption is needed because it protects access to `worker->sleeping'. As an optimisation it avoids invoking schedule() within the schedule path as part of possible wake up (thus preempt_enable_no_resched() afterwards). The io-wq has been added to the mix in the same section with disabled preemption. This breaks on PREEMPT_RT because io_wq_worker_sleeping() acquires a spinlock_t. Also within the schedule() the spinlock_t must be acquired after tsk_is_pi_blocked() otherwise it will block on the sleeping lock again while scheduling out. While playing with `io_uring-bench' I didn't notice a significant latency spike after converting io_wqe::lock to a raw_spinlock_t. The latency was more or less the same. In order to keep the spinlock_t it would have to be moved after the tsk_is_pi_blocked() check which would introduce a branch instruction into the hot path. The lock is used to maintain the `work_list' and wakes one task up at most. Should io_wqe_cancel_pending_work() cause latency spikes, while searching for a specific item, then it would need to drop the lock during iterations. revert_creds() is also invoked under the lock. According to debug cred::non_rcu is 0. Otherwise it should be moved outside of the locked section because put_cred_rcu()->free_uid() acquires a sleeping lock. Convert io_wqe::lock to a raw_spinlock_t.c Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: reference ->nsproxy for file table commandsJens Axboe2020-09-301-0/+4
| | | | | | | | | | | If we don't get and assign the namespace for the async work, then certain paths just don't work properly (like /dev/stdin, /proc/mounts, etc). Anything that references the current namespace of the given task should be assigned for async work on behalf of that task. Cc: stable@vger.kernel.org # v5.5+ Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: fix hang after cancelling pending hashed workPavel Begunkov2020-08-231-2/+19
| | | | | | | | | | | Don't forget to update wqe->hash_tail after cancelling a pending work item, if it was hashed. Cc: stable@vger.kernel.org # 5.7+ Reported-by: Dmitry Shulyak <yashulyak@gmail.com> Fixes: 86f3cd1b589a1 ("io-wq: handle hashed writes in chains") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: update hash bitsPavel Begunkov2020-07-251-4/+1
| | | | | | | | | Linked requests are hashed, remove a comment stating otherwise. Also move hash bits to emphasise that we don't carry it through loop iteration and set it every time. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: move RLIMIT_FSIZE to io-wqPavel Begunkov2020-07-241-0/+1
| | | | | | | | RLIMIT_SIZE in needed only for execution from an io-wq context, hence move all preparations from hot path to io-wq work setup. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: return next work from ->do_work() directlyPavel Begunkov2020-06-261-5/+3
| | | | | | | | | It's easier to return next work from ->do_work() than having an in-out argument. Looks nicer and easier to compile. Also, merge io_wq_assign_next() into its only user. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: cancel all task's requests on exitPavel Begunkov2020-06-151-14/+0
| | | | | | | | If a process is going away, io_uring_flush() will cancel only 1 request with a matching pid. Cancel all of them Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: add an option to cancel all matched reqsPavel Begunkov2020-06-151-26/+34
| | | | | | | | This adds support for cancelling all io-wq works matching a predicate. It isn't used yet, so no change in observable behaviour. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: reorder cancellation pending -> runningPavel Begunkov2020-06-151-22/+32
| | | | | | | | | Go all over all pending lists and cancel works there, and only then try to match running requests. No functional changes here, just a preparation for bulk cancellation. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge tag 'io_uring-5.8-2020-06-11' of git://git.kernel.dk/linux-blockLinus Torvalds2020-06-111-4/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull io_uring fixes from Jens Axboe: "A few late stragglers in here. In particular: - Validate full range for provided buffers (Bijan) - Fix bad use of kfree() in buffer registration failure (Denis) - Don't allow close of ring itself, it's not fully safe. Making it fully safe would require making the system call more expensive, which isn't worth it. - Buffer selection fix - Regression fix for O_NONBLOCK retry - Make IORING_OP_ACCEPT honor O_NONBLOCK (Jiufei) - Restrict opcode handling for SQ/IOPOLL (Pavel) - io-wq work handling cleanups and improvements (Pavel, Xiaoguang) - IOPOLL race fix (Xiaoguang)" * tag 'io_uring-5.8-2020-06-11' of git://git.kernel.dk/linux-block: io_uring: fix io_kiocb.flags modification race in IOPOLL mode io_uring: check file O_NONBLOCK state for accept io_uring: avoid unnecessary io_wq_work copy for fast poll feature io_uring: avoid whole io_wq_work copy for requests completed inline io_uring: allow O_NONBLOCK async retry io_wq: add per-wq work handler instead of per work io_uring: don't arm a timeout through work.func io_uring: remove custom ->func handlers io_uring: don't derive close state from ->func io_uring: use kvfree() in io_sqe_buffer_register() io_uring: validate the full range of provided buffers for access io_uring: re-set iov base/len for buffer select retry io_uring: move send/recv IOPOLL check into prep io_uring: deduplicate io_openat{,2}_prep() io_uring: do build_open_how() only once io_uring: fix {SQ,IO}POLL with unsupported opcodes io_uring: disallow close of ring itself
| * io_wq: add per-wq work handler instead of per workPavel Begunkov2020-06-081-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | io_uring is the only user of io-wq, and now it uses only io-wq callback for all its requests, namely io_wq_submit_work(). Instead of storing work->runner callback in each instance of io_wq_work, keep it in io-wq itself. pros: - reduces io_wq_work size - more robust -- ->func won't be invalidated with mem{cpy,set}(req) - helps other work Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | kernel: set USER_DS in kthread_use_mmChristoph Hellwig2020-06-101-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some architectures like arm64 and s390 require USER_DS to be set for kernel threads to access user address space, which is the whole purpose of kthread_use_mm, but other like x86 don't. That has lead to a huge mess where some callers are fixed up once they are tested on said architectures, while others linger around and yet other like io_uring try to do "clever" optimizations for what usually is just a trivial asignment to a member in the thread_struct for most architectures. Make kthread_use_mm set USER_DS, and kthread_unuse_mm restore to the previous value instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Jens Axboe <axboe@kernel.dk> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Felipe Balbi <balbi@kernel.org> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: http://lkml.kernel.org/r/20200404094101.672954-7-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | kernel: better document the use_mm/unuse_mm API contractChristoph Hellwig2020-06-101-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Switch the function documentation to kerneldoc comments, and add WARN_ON_ONCE asserts that the calling thread is a kernel thread and does not have ->mm set (or has ->mm set in the case of unuse_mm). Also give the functions a kthread_ prefix to better document the use case. [hch@lst.de: fix a comment typo, cover the newly merged use_mm/unuse_mm caller in vfio] Link: http://lkml.kernel.org/r/20200416053158.586887-3-hch@lst.de [sfr@canb.auug.org.au: powerpc/vas: fix up for {un}use_mm() rename] Link: http://lkml.kernel.org/r/20200422163935.5aa93ba5@canb.auug.org.au Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Jens Axboe <axboe@kernel.dk> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [usb] Acked-by: Haren Myneni <haren@linux.ibm.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Felipe Balbi <balbi@kernel.org> Cc: Jason Wang <jasowang@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Link: http://lkml.kernel.org/r/20200404094101.672954-6-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | kernel: move use_mm/unuse_mm to kthread.cChristoph Hellwig2020-06-101-1/+0
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "improve use_mm / unuse_mm", v2. This series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API. This patch (of 3): Use the proper API instead. Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de These helpers are only for use with kernel threads, and I will tie them more into the kthread infrastructure going forward. Also move the prototypes to kthread.h - mmu_context.h was a little weird to start with as it otherwise contains very low-level MM bits. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Jens Axboe <axboe@kernel.dk> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Felipe Balbi <balbi@kernel.org> Cc: Jason Wang <jasowang@redhat.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de Link: http://lkml.kernel.org/r/20200416053158.586887-1-hch@lst.de Link: http://lkml.kernel.org/r/20200404094101.672954-5-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* io_uring: use io-wq manager as backup task if task is exitingJens Axboe2020-04-031-0/+12
| | | | | | | | | | If the original task is (or has) exited, then the task work will not get queued properly. Allow for using the io-wq manager task to queue this work for execution, and ensure that the io-wq manager notices and runs this work if woken up (or exiting). Reported-by: Dan Melnic <dmm@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: handle hashed writes in chainsPavel Begunkov2020-03-231-20/+48
| | | | | | | | | | | | | | | | | | | We always punt async buffered writes to an io-wq helper, as the core kernel does not have IOCB_NOWAIT support for that. Most buffered async writes complete very quickly, as it's just a copy operation. This means that doing multiple locking roundtrips on the shared wqe lock for each buffered write is wasteful. Additionally, buffered writes are hashed work items, which means that any buffered write to a given file is serialized. Keep identicaly hashed work items contiguously in @wqe->work_list, and track a tail for each hash bucket. On dequeue of a hashed item, splice all of the same hash in one go using the tracked tail. Until the batch is done, the caller doesn't have to synchronize with the wqe or worker locks again. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: close cancel gap for hashed linked workPavel Begunkov2020-03-221-3/+7
| | | | | | | | | | | | After io_assign_current_work() of a linked work, it can be decided to offloaded to another thread so doing io_wqe_enqueue(). However, until next io_assign_current_work() it can be cancelled, that isn't handled. Don't assign it, if it's not going to be executed. Fixes: 60cf46ae6054 ("io-wq: hash dependent work") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: hash dependent workPavel Begunkov2020-03-141-6/+19
| | | | | | | | Enable io-wq hashing stuff for dependent works simply by re-enqueueing such requests. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: split hashing and enqueueingPavel Begunkov2020-03-141-9/+5
| | | | | | | | | | | | It's a preparation patch removing io_wq_enqueue_hashed(), which now should be done by io_wq_hash_work() + io_wq_enqueue(). Also, set hash value for dependant works, and do it as late as possible, because req->file can be unavailable before. This hash will be ignored by io-wq. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: don't resched if there is no workPavel Begunkov2020-03-141-4/+6
| | | | | | | | | | This little tweak restores the behaviour that was before the recent io_worker_handle_work() optimisation patches. It makes the function do cond_resched() and flush_signals() only if there is an actual work to execute. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: remove duplicated cancel codePavel Begunkov2020-03-121-112/+24
| | | | | | | | | | Deduplicate cancellation parts, as many of them looks the same, as do e.g. - io_wqe_cancel_cb_work() and io_wqe_cancel_work() - io_wq_worker_cancel() and io_work_cancel() Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring/io-wq: forward submission ref to asyncPavel Begunkov2020-03-041-15/+14
| | | | | | | | | | | | | | First it changes io-wq interfaces. It replaces {get,put}_work() with free_work(), which guaranteed to be called exactly once. It also enforces free_work() callback to be non-NULL. io_uring follows the changes and instead of putting a submission reference in io_put_req_async_completion(), it will be done in io_free_work(). As removes io_get_work() with corresponding refcount_inc(), the ref balance is maintained. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: optimise out *next_work() double lockPavel Begunkov2020-03-041-3/+6
| | | | | | | | | | When executing non-linked hashed work, io_worker_handle_work() will lock-unlock wqe->lock to update hash, and then immediately lock-unlock to get next work. Optimise this case and do lock/unlock only once. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: optimise locking in io_worker_handle_work()Pavel Begunkov2020-03-041-8/+7
| | | | | | | | | | | | | | | There are 2 optimisations: - Now, io_worker_handler_work() do io_assign_current_work() twice per request, and each one adds lock/unlock(worker->lock) pair. The first is to reset worker->cur_work to NULL, and the second to set a real work shortly after. If there is a dependant work, set it immediately, that effectively removes the extra NULL'ing. - And there is no use in taking wqe->lock for linked works, as they are not hashed now. Optimise it out. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: shuffle io_worker_handle_work() codePavel Begunkov2020-03-041-59/+64
| | | | | | | | | | | | This is a preparation patch, it adds some helpers and makes the next patches cleaner. - extract io_impersonate_work() and io_assign_current_work() - replace @next label with nested do-while - move put_work() right after NULL'ing cur_work. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: use BIT for ulong hashPavel Begunkov2020-03-021-3/+3
| | | | | | | | @hash_map is unsigned long, but BIT_ULL() is used for manipulations. BIT() is a better match as it returns exactly unsigned long value. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: remove IO_WQ_WORK_CBPavel Begunkov2020-03-021-3/+0
| | | | | | | | | | | | | | IO_WQ_WORK_CB is used only for linked timeouts, which will be armed before the work setup (i.e. mm, override creds, etc). The setup shouldn't take long, so it's ok to arm it a bit later and get rid of IO_WQ_WORK_CB. Make io-wq call work->func() only once, callbacks will handle the rest. i.e. the linked timeout handler will do the actual issue. And as a bonus, it removes an extra indirect call. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: remove unused IO_WQ_WORK_HAS_MMPavel Begunkov2020-03-021-2/+0
| | | | | | | IO_WQ_WORK_HAS_MM is set but never used, remove it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: remove io_wq_flush and IO_WQ_WORK_INTERNALPavel Begunkov2020-03-021-37/+1
| | | | | | | | | | | | | io_wq_flush() is buggy, during cancelation of a flush, the associated work may be passed to the caller's (i.e. io_uring) @match callback. That callback is expecting it to be embedded in struct io_kiocb. Cancelation of internal work probably doesn't make a lot of sense to begin with. As the flush helper is no longer used, just delete it and the associated work flag. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: fix IO_WQ_WORK_NO_CANCEL cancellationPavel Begunkov2020-03-021-6/+14
| | | | | | | | | | | To cancel a work, io-wq sets IO_WQ_WORK_CANCEL and executes the callback. However, IO_WQ_WORK_NO_CANCEL works will just execute and may return next work, which will be ignored and lost. Cancel the whole link. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: remove spin-for-work optimizationJens Axboe2020-02-251-19/+0
| | | | | | | | | | | | Andres reports that buffered IO seems to suck up more cycles than we would like, and he narrowed it down to the fact that the io-wq workers will briefly spin for more work on completion of a work item. This was a win on the networking side, but apparently some other cases take a hit because of it. Remove the optimization to avoid burning more CPU than we have to for disk IO. Reported-by: Andres Freund <andres@anarazel.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: don't call kXalloc_node() with non-online nodeJens Axboe2020-02-121-4/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Glauber reports a crash on init on a box he has: RIP: 0010:__alloc_pages_nodemask+0x132/0x340 Code: 18 01 75 04 41 80 ce 80 89 e8 48 8b 54 24 08 8b 74 24 1c c1 e8 0c 48 8b 3c 24 83 e0 01 88 44 24 20 48 85 d2 0f 85 74 01 00 00 <3b> 77 08 0f 82 6b 01 00 00 48 89 7c 24 10 89 ea 48 8b 07 b9 00 02 RSP: 0018:ffffb8be4d0b7c28 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000e8e8 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000002080 RBP: 0000000000012cc0 R08: 0000000000000000 R09: 0000000000000002 R10: 0000000000000dc0 R11: ffff995c60400100 R12: 0000000000000000 R13: 0000000000012cc0 R14: 0000000000000001 R15: ffff995c60db00f0 FS: 00007f4d115ca900(0000) GS:ffff995c60d80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000002088 CR3: 00000017cca66002 CR4: 00000000007606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: alloc_slab_page+0x46/0x320 new_slab+0x9d/0x4e0 ___slab_alloc+0x507/0x6a0 ? io_wq_create+0xb4/0x2a0 __slab_alloc+0x1c/0x30 kmem_cache_alloc_node_trace+0xa6/0x260 io_wq_create+0xb4/0x2a0 io_uring_setup+0x97f/0xaa0 ? io_remove_personalities+0x30/0x30 ? io_poll_trigger_evfd+0x30/0x30 do_syscall_64+0x5b/0x1c0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f4d116cb1ed which is due to the 'wqe' and 'worker' allocation being node affine. But it isn't valid to call the node affine allocation if the node isn't online. Setup structures for even offline nodes, as usual, but skip them in terms of thread setup to not waste resources. If the node isn't online, just alloc memory with NUMA_NO_NODE. Reported-by: Glauber Costa <glauber@scylladb.com> Tested-by: Glauber Costa <glauber@scylladb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: add io_wq_cancel_pid() to cancel based on a specific pidJens Axboe2020-02-091-0/+29
| | | | | | | | Add a helper that allows the caller to cancel work based on what mm it belongs to. This allows io_uring to cancel work from a given task or thread when it exits. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: make io_wqe_cancel_work() take a match handlerJens Axboe2020-02-091-11/+22
| | | | | | | | | | | We want to use the cancel functionality for canceling based on not just the work itself. Instead of matching on the work address manually, allow a match handler to tell us if we found the right work item or not. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: add support for inheriting ->fsJens Axboe2020-02-081-0/+8
| | | | | | | | Some work items need this for relative path lookup, make it available like the other inherited credentials/mm/etc. Cc: stable@vger.kernel.org # 5.3+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io_uring: fix linked command file table usageJens Axboe2020-01-291-2/+1
| | | | | | | | | | | | | We're not consistent in how the file table is grabbed and assigned if we have a command linked that requires the use of it. Add ->file_table to the io_op_defs[] array, and use that to determine when to grab the table instead of having the handlers set it if they need to defer. This also means we can kill the IO_WQ_WORK_NEEDS_FILES flag. We always initialize work->files, so io-wq can just check for that. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* io-wq: allow grabbing existing io-wqPavel Begunkov2020-01-281-0/+8
| | | | | | | | | Export a helper to attach to an existing io-wq, rather than setting up a new one. This is doable now that we have reference counted io_wq's. Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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