kernel/linux.git/io_uring/rw.c, branch linux-6.0.y

io_uring: remove iopoll spinlock

2022-12-31T12:26:53+00:00

commit 2dac1a159216b39ced8d78dba590c5d2f4249586 upstream. This reverts commit 2ccc92f4effcfa1c51c4fcf1e34d769099d3cad4 io_req_complete_post() should now behave well even in case of IOPOLL, we can remove completion_lock locking. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/7e171c8b530656b14a671c59100ca260e46e7f2a.1669203009.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: add completion locking for iopoll

2022-12-31T12:26:53+00:00

commit 2ccc92f4effcfa1c51c4fcf1e34d769099d3cad4 upstream. There are pieces of code that may allow iopoll to race filling cqes, temporarily add spinlocking around posting events. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/84d86b5c117feda075471c5c9e65208e0dccf5d0.1669203009.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rw: remove leftover debug statement

2022-10-29T08:08:33+00:00

[ Upstream commit 5c61795ea97c170347c5c4af0c159bd877b8af71 ] This debug statement was never meant to go into the upstream release, kill it off before it ends up in a release. It was just part of the testing for the initial version of the patch. Fixes: 2ec33a6c3cca ("io_uring/rw: ensure kiocb_end_write() is always called") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring/rw: ensure kiocb_end_write() is always called

2022-10-21T10:39:29+00:00

commit 2ec33a6c3cca9fe2465e82050c81f5ffdc508b36 upstream. A previous commit moved the notifications and end-write handling, but it is now missing a few spots where we also want to call both of those. Without that, we can potentially be missing file notifications, and more importantly, have an imbalance in the super_block writers sem accounting. Fixes: b000145e9907 ("io_uring/rw: defer fsnotify calls to task context") Reported-by: Dave Chinner Link: https://lore.kernel.org/all/20221010050319.GC2703033@dread.disaster.area/ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rw: defer fsnotify calls to task context

2022-10-21T10:38:52+00:00

[ Upstream commit b000145e9907809406d8164c3b2b8861d95aecd1 ] We can't call these off the kiocb completion as that might be off soft/hard irq context. Defer the calls to when we process the task_work for this request. That avoids valid complaints like: stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:3961 [inline] valid_state kernel/locking/lockdep.c:3973 [inline] mark_lock_irq kernel/locking/lockdep.c:4176 [inline] mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632 mark_lock kernel/locking/lockdep.c:4596 [inline] mark_usage kernel/locking/lockdep.c:4527 [inline] __lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc mm/slab.c:3278 [inline] __kmem_cache_alloc_lru mm/slab.c:3471 [inline] kmem_cache_alloc+0x39/0x520 mm/slab.c:3491 fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline] fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline] fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948 send_to_group fs/notify/fsnotify.c:360 [inline] fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570 __fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230 fsnotify_parent include/linux/fsnotify.h:77 [inline] fsnotify_file include/linux/fsnotify.h:99 [inline] fsnotify_access include/linux/fsnotify.h:309 [inline] __io_complete_rw_common+0x485/0x720 io_uring/rw.c:195 io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228 iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline] iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178 bio_endio+0x5f9/0x780 block/bio.c:1564 req_bio_endio block/blk-mq.c:695 [inline] blk_update_request+0x3fc/0x1300 block/blk-mq.c:825 scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541 scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971 scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438 blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240 Fixes: f63cf5192fe3 ("io_uring: ensure that fsnotify is always called") Link: https://lore.kernel.org/all/20220929135627.ykivmdks2w5vzrwg@quack3/ Reported-by: syzbot+dfcc5f4da15868df7d4d@syzkaller.appspotmail.com Reported-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring/rw: don't lose short results on io_setup_async_rw()

2022-10-21T10:37:33+00:00

commit c278d9f8ac0db5590909e6d9e85b5ca2b786704f upstream. If a retry io_setup_async_rw() fails we lose result from the first io_iter_do_read(), which is a problem mostly for streams/sockets. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/0e8d20cebe5fc9c96ed268463c394237daabc384.1664235732.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rw: fix unexpected link breakage

2022-10-21T10:37:33+00:00

commit bf68b5b34311ee57ed40749a1257a30b46127556 upstream. req->cqe.res is set in io_read() to the amount of bytes left to be done, which is used to figure out whether to fail a read or not. However, io_read() may do another without returning, and we stash the previous value into ->bytes_done but forget to update cqe.res. Then we ask a read to do strictly less than cqe.res but expect the return to be exactly cqe.res. Fix the bug by updating cqe.res for retries. Cc: stable@vger.kernel.org Reported-and-Tested-by: Beld Zhang Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/3a1088440c7be98e5800267af922a67da0ef9f13.1664235732.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rw: don't lose partial IO result on fail

2022-10-21T10:37:32+00:00

commit 47b4c68660752facfa6247b1fc9ca9d722b8b601 upstream. A partially done read/write may end up in io_req_complete_failed() and loose the result, make sure we return the number of bytes processed. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/05e0879c226bcd53b441bf92868eadd4bf04e2fc.1663668091.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/rw: fix error'ed retry return values

2022-09-13T13:47:11+00:00

Kernel test robot reports that we test negativity of an unsigned in io_fixup_rw_res() after a recent change, which masks error codes and messes up the return value in case I/O is re-retried and failed with an error. Fixes: 4d9cb92ca41dd ("io_uring/rw: fix short rw error handling") Reported-by: kernel test robot Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/9754a0970af1861e7865f9014f735c70dc60bf79.1663071587.git.asml.silence@gmail.com Signed-off-by: Jens Axboe

io_uring/rw: fix short rw error handling

2022-09-09T14:57:57+00:00

We have a couple of problems, first reports of unexpected link breakage for reads when cqe->res indicates that the IO was done in full. The reason here is partial IO with retries. TL;DR; we compare the result in __io_complete_rw_common() against req->cqe.res, but req->cqe.res doesn't store the full length but rather the length left to be done. So, when we pass the full corrected result via kiocb_done() -> __io_complete_rw_common(), it fails. The second problem is that we don't try to correct res in io_complete_rw(), which, for instance, might be a problem for O_DIRECT but when a prefix of data was cached in the page cache. We also definitely don't want to pass a corrected result into io_rw_done(). The fix here is to leave __io_complete_rw_common() alone, always pass not corrected result into it and fix it up as the last step just before actually finishing the I/O. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Link: https://github.com/axboe/liburing/issues/643 Reported-by: Beld Zhang Signed-off-by: Jens Axboe