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2023-03-09io_uring: silence variable ‘prev’ set but not used warningJens Axboe1-2/+2
If io_uring.o is built with W=1, it triggers a warning: io_uring/io_uring.c: In function ‘__io_submit_flush_completions’: io_uring/io_uring.c:1502:40: warning: variable ‘prev’ set but not used [-Wunused-but-set-variable] 1502 | struct io_wq_work_node *node, *prev; | ^~~~ which is due to the wq_list_for_each() iterator always keeping a 'prev' variable. Most users need this to remove an entry from a list, for example, but __io_submit_flush_completions() never does that. Add a basic helper that doesn't track prev instead, and use that in that function. Reported-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-03-03Merge tag 'io_uring-6.3-2023-03-03' of git://git.kernel.dk/linuxLinus Torvalds1-16/+16
Pull more io_uring updates from Jens Axboe: "Here's a set of fixes/changes that didn't make the first cut, either because they got queued before I sent the early merge request, or fixes that came in afterwards. In detail: - Don't set MSG_NOSIGNAL on recv/recvmsg opcodes, as AF_PACKET will error out (David) - Fix for spurious poll wakeups (me) - Fix for a file leak for buffered reads in certain conditions (Joseph) - Don't allow registered buffers of mixed types (Pavel) - Improve handling of huge pages for registered buffers (Pavel) - Provided buffer ring size calculation fix (Wojciech) - Minor cleanups (me)" * tag 'io_uring-6.3-2023-03-03' of git://git.kernel.dk/linux: io_uring/poll: don't pass in wake func to io_init_poll_iocb() io_uring: fix fget leak when fs don't support nowait buffered read io_uring/poll: allow some retries for poll triggering spuriously io_uring: remove MSG_NOSIGNAL from recvmsg io_uring/rsrc: always initialize 'folio' to NULL io_uring/rsrc: optimise registered huge pages io_uring/rsrc: optimise single entry advance io_uring/rsrc: disallow multi-source reg buffers io_uring: remove unused wq_list_merge io_uring: fix size calculation when registering buf ring io_uring/rsrc: fix a comment in io_import_fixed() io_uring: rename 'in_idle' to 'in_cancel' io_uring: consolidate the put_ref-and-return section of adding work
2023-02-28io_uring: fix fget leak when fs don't support nowait buffered readJoseph Qi1-1/+1
Heming reported a BUG when using io_uring doing link-cp on ocfs2. [1] Do the following steps can reproduce this BUG: mount -t ocfs2 /dev/vdc /mnt/ocfs2 cp testfile /mnt/ocfs2/ ./link-cp /mnt/ocfs2/testfile /mnt/ocfs2/testfile.1 umount /mnt/ocfs2 Then umount will fail, and it outputs: umount: /mnt/ocfs2: target is busy. While tracing umount, it blames mnt_get_count() not return as expected. Do a deep investigation for fget()/fput() on related code flow, I've finally found that fget() leaks since ocfs2 doesn't support nowait buffered read. io_issue_sqe |-io_assign_file // do fget() first |-io_read |-io_iter_do_read |-ocfs2_file_read_iter // return -EOPNOTSUPP |-kiocb_done |-io_rw_done |-__io_complete_rw_common // set REQ_F_REISSUE |-io_resubmit_prep |-io_req_prep_async // override req->file, leak happens This was introduced by commit a196c78b5443 in v5.18. Fix it by don't re-assign req->file if it has already been assigned. [1] https://lore.kernel.org/ocfs2-devel/ab580a75-91c8-d68a-3455-40361be1bfa8@linux.alibaba.com/T/#t Fixes: a196c78b5443 ("io_uring: assign non-fixed early for async work") Cc: <stable@vger.kernel.org> Reported-by: Heming Zhao <heming.zhao@suse.com> Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Link: https://lore.kernel.org/r/20230228045459.13524-1-joseph.qi@linux.alibaba.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-24Merge tag 'mm-stable-2023-02-20-13-37' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Daniel Verkamp has contributed a memfd series ("mm/memfd: add F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". * tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits) include/linux/migrate.h: remove unneeded externs mm/memory_hotplug: cleanup return value handing in do_migrate_range() mm/uffd: fix comment in handling pte markers mm: change to return bool for isolate_movable_page() mm: hugetlb: change to return bool for isolate_hugetlb() mm: change to return bool for isolate_lru_page() mm: change to return bool for folio_isolate_lru() objtool: add UACCESS exceptions for __tsan_volatile_read/write kmsan: disable ftrace in kmsan core code kasan: mark addr_has_metadata __always_inline mm: memcontrol: rename memcg_kmem_enabled() sh: initialize max_mapnr m68k/nommu: add missing definition of ARCH_PFN_OFFSET mm: percpu: fix incorrect size in pcpu_obj_full_size() maple_tree: reduce stack usage with gcc-9 and earlier mm: page_alloc: call panic() when memoryless node allocation fails mm: multi-gen LRU: avoid futile retries migrate_pages: move THP/hugetlb migration support check to simplify code migrate_pages: batch flushing TLB migrate_pages: share more code between _unmap and _move ...
2023-02-22io_uring: rename 'in_idle' to 'in_cancel'Jens Axboe1-9/+9
This better describes what it does - it's incremented when the task is currently undergoing a cancelation operation, due to exiting or exec'ing. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-22io_uring: consolidate the put_ref-and-return section of adding workJens Axboe1-6/+6
We've got a few cases of this, move them to one section and just use gotos to get there. Reduces the text section on both arm64 and x86-64, using gcc-12.2. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-16io_uring: Support calling io_uring_register with a registered ring fdJosh Triplett1-7/+26
Add a new flag IORING_REGISTER_USE_REGISTERED_RING (set via the high bit of the opcode) to treat the fd as a registered index rather than a file descriptor. This makes it possible for a library to open an io_uring, register the ring fd, close the ring fd, and subsequently use the ring entirely via registered index. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Link: https://lore.kernel.org/r/f2396369e638284586b069dbddffb8c992afba95.1676419314.git.josh@joshtriplett.org [axboe: remove extra high bit clear] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: if a linked request has REQ_F_FORCE_ASYNC then run it asyncDylan Yudaken1-3/+5
REQ_F_FORCE_ASYNC was being ignored for re-queueing linked requests. Instead obey that flag. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20230127135227.3646353-2-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: add reschedule point to handle_tw_list()Jens Axboe1-1/+7
If CONFIG_PREEMPT_NONE is set and the task_work chains are long, we could be running into issues blocking others for too long. Add a reschedule check in handle_tw_list(), and flush the ctx if we need to reschedule. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: add a conditional reschedule to the IOPOLL cancelation loopJens Axboe1-0/+1
If the kernel is configured with CONFIG_PREEMPT_NONE, we could be sitting in a tight loop reaping events but not giving them a chance to finish. This results in a trace ala: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 2-...!: (5249 ticks this GP) idle=935c/1/0x4000000000000000 softirq=4265/4274 fqs=1 (t=5251 jiffies g=465 q=4135 ncpus=4) rcu: rcu_sched kthread starved for 5249 jiffies! g465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_sched state:R running task stack:0 pid:12 ppid:2 flags:0x00000008 Call trace: __switch_to+0xb0/0xc8 __schedule+0x43c/0x520 schedule+0x4c/0x98 schedule_timeout+0xbc/0xdc rcu_gp_fqs_loop+0x308/0x344 rcu_gp_kthread+0xd8/0xf0 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 0: task:kworker/u8:10 state:R running task stack:0 pid:89 ppid:2 flags:0x0000000a Workqueue: events_unbound io_ring_exit_work Call trace: __switch_to+0xb0/0xc8 0xffff0000c8fefd28 CPU: 2 PID: 95 Comm: kworker/u8:13 Not tainted 6.2.0-rc5-00042-g40316e337c80-dirty #2759 Hardware name: linux,dummy-virt (DT) Workqueue: events_unbound io_ring_exit_work pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : io_do_iopoll+0x344/0x360 lr : io_do_iopoll+0xb8/0x360 sp : ffff800009bebc60 x29: ffff800009bebc60 x28: 0000000000000000 x27: 0000000000000000 x26: ffff0000c0f67d48 x25: ffff0000c0f67840 x24: ffff800008950024 x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c27d3200 x20: ffff0000c0f67840 x19: ffff0000c0f67800 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000001 x13: 0000000000000001 x12: 0000000000000000 x11: 0000000000000179 x10: 0000000000000870 x9 : ffff800009bebd60 x8 : ffff0000c27d3ad0 x7 : fefefefefefefeff x6 : 0000646e756f626e x5 : ffff0000c0f67840 x4 : 0000000000000000 x3 : ffff0000c2398000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: io_do_iopoll+0x344/0x360 io_uring_try_cancel_requests+0x21c/0x334 io_ring_exit_work+0x90/0x40c process_one_work+0x1a4/0x254 worker_thread+0x1ec/0x258 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 Add a cond_resched() in the cancelation IOPOLL loop to fix this. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: return normal tw run linking optimisationPavel Begunkov1-0/+9
io_submit_flush_completions() may produce new task_work items, so it's a good idea to recheck the task_work list after flushing completions. The optimisation is not new and was accidentially removed by f88262e60bb9 ("io_uring: lockless task list") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a7ed5ede84de190832cc33ebbcdd6e91cd90f5b6.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: refactor tctx_task_workPavel Begunkov1-8/+5
Merge almost identical sections of tctx_task_work(), this will make code modifications later easier and also inlines handle_tw_list(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d06592d91e3e7559e7a4dbb8907d110863008dc7.1674484266.git.asml.silence@gmail.com [axboe: fold in setting count to zero patch from Tom Rix] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: refactor io_put_task helpersPavel Begunkov1-5/+12
Add a helper for putting refs from the target task context, rename __io_put_task() and add a couple of comments around. Use the remote version for __io_req_complete_post(), the local is only needed for __io_submit_flush_completions(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3bf92ebd594769d8a5d648472a8e335f2031d542.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: refactor req allocationPavel Begunkov1-4/+3
Follow the io_get_sqe pattern returning the result via a pointer and hide request cache refill inside io_alloc_req(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8c37c2e8a3cb5e4cd6a8ae3b91371227a92708a6.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: improve io_get_sqePavel Begunkov1-5/+5
Return an SQE from io_get_sqe() as a parameter and use the return value to determine if it failed or not. This enables the compiler to compile out the sqe NULL check when we know that the return SQE is valid. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9cceb11329240ea097dffef6bf0a675bca14cf42.1674484266.git.asml.silence@gmail.com [axboe: remove bogus const modifier on return value] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: kill outdated comment about overflow flushPavel Begunkov1-1/+0
__io_cqring_overflow_flush() doesn't return anything anymore, remove outdate comment. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/4ce2bcbb17eac80cdf883fd1459d5ee6586e238c.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: use user visible tail in io_uring_poll()Pavel Begunkov1-1/+1
We return POLLIN from io_uring_poll() depending on whether there are CQEs for the userspace, and so we should use the user visible tail pointer instead of a transient cached value. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/228ffcbf30ba98856f66ffdb9a6a60ead1dd96c0.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: pass in io_issue_def to io_assign_file()Jens Axboe1-4/+5
This generates better code for me, avoiding an extra load on arm64, and both call sites already have this variable available for easy passing. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: Enable KASAN for request cacheBreno Leitao1-1/+2
Every io_uring request is represented by struct io_kiocb, which is cached locally by io_uring (not SLAB/SLUB) in the list called submit_state.freelist. This patch simply enabled KASAN for this free list. This list is initially created by KMEM_CACHE, but later, managed by io_uring. This patch basically poisons the objects that are not used (i.e., they are the free list), and unpoisons it when the object is allocated/removed from the list. Touching these poisoned objects while in the freelist will cause a KASAN warning. Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: Split io_issue_def structBreno Leitao1-7/+8
This patch removes some "cold" fields from `struct io_issue_def`. The plan is to keep only highly used fields into `struct io_issue_def`, so, it may be hot in the cache. The hot fields are basically all the bitfields and the callback functions for .issue and .prep. The other less frequently used fields are now located in a secondary and cold struct, called `io_cold_def`. This is the size for the structs: Before: io_issue_def = 56 bytes After: io_issue_def = 24 bytes; io_cold_def = 40 bytes Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20230112144411.2624698-2-leitao@debian.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: Rename struct io_op_defBreno Leitao1-13/+13
The current io_op_def struct is becoming huge and the name is a bit generic. The goal of this patch is to rename this struct to `io_issue_def`. This struct will contain the hot functions associated with the issue code path. For now, this patch only renames the structure, and an upcoming patch will break up the structure in two, moving the non-issue fields to a secondary struct. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20230112144411.2624698-1-leitao@debian.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: refactor __io_req_complete_postPavel Begunkov1-2/+2
Keep parts of __io_req_complete_post() relying on req->flags together so the value can be cached. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2b4fbb42f404a0e75c4d9f0a5b16f314a839d0a9.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: simplify fallback executionPavel Begunkov1-8/+6
Lock the ring with uring_lock in io_fallback_req_func(), which should make it a bit safer and easier. With that we also don't need refs pinning as io_ring_exit_work() will wait until uring_lock is freed. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/56170e6a0cbfc8edee2794c6613e8f6f1d76d276.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: don't export io_put_task()Pavel Begunkov1-1/+10
io_put_task() is only used in uring.c so enclose it there together with __io_put_task(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/43c7f9227e2ab215f1a6069dadbc5382bed346fe.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: return back links tw run optimisationPavel Begunkov1-1/+4
io_submit_flush_completions() may queue new requests for tw execution, especially true for linked requests. Recheck the tw list for emptiness after flushing completions. Note that this doesn't really fix the commit referenced below, but it does reinstate an optimization that existed before that got merged. Fixes: f88262e60bb9 ("io_uring: lockless task list") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/6328acdbb5e60efc762b18003382de077e6e1367.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: make io_sqpoll_wait_sq return voidQuanfa Fu1-5/+3
Change the return type to void since it always return 0, and no need to do the checking in syscall io_uring_enter. Signed-off-by: Quanfa Fu <quanfafu@gmail.com> Link: https://lore.kernel.org/r/20230115071519.554282-1-quanfafu@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: optimise deferred tw executionPavel Begunkov1-17/+7
We needed fake nodes in __io_run_local_work() and to avoid unecessary wake ups while the task already running task_works, but we don't need them anymore since wake ups are protected by cq_waiting, which is always cleared by the time we're executing deferred task_work items. Note that because of loose sync around cq_waiting clearing io_req_local_work_add() may wake the task more than once, but that's fine and should be rare to not hurt perf. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8839534891f0a2f1076e78554a31ea7e099f7de5.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: add io_req_local_work_add wake fast pathPavel Begunkov1-1/+6
Don't wake the master task after queueing a deferred tw unless it's currently waiting in io_cqring_wait. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/717702d772825a6647e6c315b4690277ba84c3fc.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: waitqueue-less cq waitingPavel Begunkov1-7/+12
With DEFER_TASKRUN only ctx->submitter_task might be waiting for CQEs, we can use this to optimise io_cqring_wait(). Replace ->cq_wait waitqueue with waking the task directly. It works but misses an important optimisation covered by the following patch, so this patch without follow ups might hurt performance. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/103d174d35d919d4cb0922d8a9c93a8f0c35f74a.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: wake up optimisationsPavel Begunkov1-1/+20
Flush completions is done either from the submit syscall or by the task_work, both are in the context of the submitter task, and when it goes for a single threaded rings like implied by ->task_complete, there won't be any waiters on ->cq_wait but the master task. That means that there can be no tasks sleeping on cq_wait while we run __io_submit_flush_completions() and so waking up can be skipped. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/60ad9768ec74435a0ddaa6eec0ffa7729474f69f.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: add lazy poll_wq activationPavel Begunkov1-1/+59
Even though io_poll_wq_wake()'s waitqueue_active reuses a barrier we do for another waitqueue, it's not going to be the case in the future and so we want to have a fast path for it when the ring has never been polled. Move poll_wq wake ups into __io_commit_cqring_flush() using a new flag called ->poll_activated. The idea behind the flag is to set it when the ring was polled for the first time. This requires additional sync to not miss events, which is done here by using task_work for ->task_complete rings, and by default enabling the flag for all other types of rings. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/060785e8e9137a920b232c0c7f575b131af19cac.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: separate wq for ring pollingPavel Begunkov1-1/+2
Don't use ->cq_wait for ring polling but add a separate wait queue for it. We need it for following patches. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/dea0be0bf990503443c5c6c337fc66824af7d590.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: move io_run_local_work_lockedPavel Begunkov1-1/+17
io_run_local_work_locked() is only used in io_uring.c, move it there. With that we can also make __io_run_local_work() static. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/91757bcb33e5774e49fed6f2b6e058630608119b.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: mark io_run_local_work staticPavel Begunkov1-1/+1
io_run_local_work is enclosed in io_uring.c, we don't need to export it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b477fb81f5e77044f724a06fe245d5c078659364.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: don't set TASK_RUNNING in local tw runnerPavel Begunkov1-3/+2
The CQ waiting loop sets TASK_RUNNING before trying to execute task_work, no need to repeat it in io_run_local_work(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9d9422c429ef3f9457b4f4b8288bf4789564f33b.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: refactor io_wake_functionPavel Begunkov1-4/+2
Remove a local variable ctx in io_wake_function(), we don't need it if io_should_wake() triggers it to wake up. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/e60eb1008aebe286aab7d34c772ed01c447bddb1.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: keep timeout in io_wait_queuePavel Begunkov1-14/+14
Move waiting timeout into io_wait_queue Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/e4b48a9e26a3b1cf97c80121e62d4b5ab873d28d.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: optimise non-timeout waitingPavel Begunkov1-1/+3
Unlike the jiffy scheduling version, schedule_hrtimeout() jumps a few functions before getting into schedule() even if there is no actual timeout needed. Some tests showed that it takes up to 1% of CPU cycles. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/89f880574eceee6f4899783377ead234df7b3d04.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: set TASK_RUNNING right after schedulePavel Begunkov1-3/+2
Instead of constantly watching that the state of the task is running before executing tw or taking locks in io_cqring_wait(), switch it back to TASK_RUNNING immediately. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/246dddee247d89fd52023f785ed17cc34962a008.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: simplify io_has_workPavel Begunkov1-2/+1
->work_llist should never be non-empty for a non DEFER_TASKRUN ring, so we can safely skip checking the flag. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/26af9f73c09a56c9a035f94db56127358688f3aa.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: mimimise io_cqring_wait_schedulePavel Begunkov1-16/+23
io_cqring_wait_schedule() is called after we started waiting on the cq wq and set the state to TASK_INTERRUPTIBLE, for that reason we have to constantly worry whether we has returned the state back to running or not. Leave only quick checks in io_cqring_wait_schedule() and move the rest including running task work to the callers. Note, we run tw in the loop after the sched checks because of the fast path in the beginning of the function. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2814fabe75e2e019e7ca43ea07daa94564349805.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: parse check_cq out of wq waitingPavel Begunkov1-14/+18
We already avoid flushing overflows in io_cqring_wait_schedule() but only return an error for the outer loop to handle it. Minimise it even further by moving all ->check_cq parsing there. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9dfcec3121013f98208dbf79368d636d74e1231a.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: move defer tw task checksPavel Begunkov1-9/+6
Most places that want to run local tw explicitly and in advance check if they are allowed to do so. Don't rely on a similar check in __io_run_local_work(), leave it as a just-in-case warning and make sure callers checks capabilities themselves. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/990fe0e8e70fd4d57e43625e5ce8fba584821d1a.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: kill io_run_task_work_ctxPavel Begunkov1-1/+5
There is only one user of io_run_task_work_ctx(), inline it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/40953c65f7c88fb00cdc4d870ca5d5319fb3d7ea.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: don't iterate cq wait fast pathPavel Begunkov1-10/+8
Task work runners keep running until all queues tw items are exhausted. It's also rare for defer tw to queue normal tw and vise versa. Taking it into account, there is only a dim chance that further iterating the io_cqring_wait() fast path will get us anything and so we can remove the loop there. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/1f9565726661266abaa5d921e97433c831759ecf.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-30io_uring: rearrange defer list checksPavel Begunkov1-3/+0
There should be nothing in the ->work_llist for non DEFER_TASKRUN rings, so we can skip flag checks and test the list emptiness directly. Also move it out of io_run_local_work() for inlining. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/331d63fd15ca79b35b95c82a82d9246110686392.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-27io_uring: always prep_async for drain requestsDylan Yudaken1-10/+8
Drain requests all go through io_drain_req, which has a quick exit in case there is nothing pending (ie the drain is not useful). In that case it can run the issue the request immediately. However for safety it queues it through task work. The problem is that in this case the request is run asynchronously, but the async work has not been prepared through io_req_prep_async. This has not been a problem up to now, as the task work always would run before returning to userspace, and so the user would not have a chance to race with it. However - with IORING_SETUP_DEFER_TASKRUN - this is no longer the case and the work might be defered, giving userspace a chance to change data being referred to in the request. Instead _always_ prep_async for drain requests, which is simpler anyway and removes this issue. Cc: stable@vger.kernel.org Fixes: c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN") Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20230127105911.2420061-1-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-20io_uring/msg_ring: fix remote queue to disabled ringPavel Begunkov1-2/+2
IORING_SETUP_R_DISABLED rings don't have the submitter task set, so it's not always safe to use ->submitter_task. Disallow posting msg_ring messaged to disabled rings. Also add task NULL check for loosy sync around testing for IORING_SETUP_R_DISABLED. Cc: stable@vger.kernel.org Fixes: 6d043ee1164ca ("io_uring: do msg_ring in target task via tw") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-19mm/nommu: factor out check for NOMMU shared mappings into ↵David Hildenbrand1-1/+1
is_nommu_shared_mapping() Patch series "mm/nommu: don't use VM_MAYSHARE for MAP_PRIVATE mappings". Trying to reduce the confusion around VM_SHARED and VM_MAYSHARE first requires !CONFIG_MMU to stop using VM_MAYSHARE for MAP_PRIVATE mappings. CONFIG_MMU only sets VM_MAYSHARE for MAP_SHARED mappings. This paves the way for further VM_MAYSHARE and VM_SHARED cleanups: for example, renaming VM_MAYSHARED to VM_MAP_SHARED to make it cleaner what is actually means. Let's first get the weird case out of the way and not use VM_MAYSHARE in MAP_PRIVATE mappings, using a new VM_MAYOVERLAY flag instead. This patch (of 3): We want to stop using VM_MAYSHARE in private mappings to pave the way for clarifying the semantics of VM_MAYSHARE vs. VM_SHARED and reduce the confusion. While CONFIG_MMU uses VM_MAYSHARE to represent MAP_SHARED, !CONFIG_MMU also sets VM_MAYSHARE for selected R/O private file mappings that are an effective overlay of a file mapping. Let's factor out all relevant VM_MAYSHARE checks in !CONFIG_MMU code into is_nommu_shared_mapping() first. Note that whenever VM_SHARED is set, VM_MAYSHARE must be set as well (unless there is a serious BUG). So there is not need to test for VM_SHARED manually. No functional change intended. Link: https://lkml.kernel.org/r/20230102160856.500584-1-david@redhat.com Link: https://lkml.kernel.org/r/20230102160856.500584-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Nicolas Pitre <nico@fluxnic.net> Cc: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-01-05io_uring: fix CQ waiting timeout handlingPavel Begunkov1-3/+3
Jiffy to ktime CQ waiting conversion broke how we treat timeouts, in particular we rearm it anew every time we get into io_cqring_wait_schedule() without adjusting the timeout. Waiting for 2 CQEs and getting a task_work in the middle may double the timeout value, or even worse in some cases task may wait indefinitely. Cc: stable@vger.kernel.org Fixes: 228339662b398 ("io_uring: don't convert to jiffies for waiting on timeouts") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/f7bffddd71b08f28a877d44d37ac953ddb01590d.1672915663.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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