linux.git/io_uring/rw.c, branch v6.1.2

io_uring: remove iopoll spinlock

2022-12-31T12:33:12+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

2022-12-31T12:33:11+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

2022-10-16T23:24:10+00:00

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

io_uring/rw: ensure kiocb_end_write() is always called

2022-10-12T22:30:56+00:00

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

io_uring: local variable rw shadows outer variable in io_write

2022-10-12T22:30:56+00:00

This fixes the shadowing of the outer variable rw in the function
io_write(). No issue is caused by this, but let's silence the shadowing
warning anyway.

Reported-by: kernel test robot 
Signed-off-by: Stefan Roesch 
Link: https://lore.kernel.org/r/20221010234330.244244-1-shr@devkernel.io
Signed-off-by: Jens Axboe

io_uring/rw: defer fsnotify calls to task context

2022-09-29T17:00:41+00:00

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

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

2022-09-27T00:44:15+00:00

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

io_uring/rw: fix unexpected link breakage

2022-09-27T00:44:15+00:00

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

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

2022-09-21T19:15:02+00:00

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

io_uring: allow buffer recycling in READV

2022-09-21T16:30:43+00:00

In commit 934447a603b2 ("io_uring: do not recycle buffer in READV") a
temporary fix was put in io_kbuf_recycle to simply never recycle READV
buffers.

Instead of that, rather treat READV with REQ_F_BUFFER_SELECTED the same as
a READ with REQ_F_BUFFER_SELECTED. Since READV requires iov_len of 1 they
are essentially the same.
In order to do this inside io_prep_rw() add some validation to check that
it is in fact only length 1, and also extract the length of the buffer at
prep time.

This allows removal of the io_iov_buffer_select codepaths as they are only
used from the READV op.

Signed-off-by: Dylan Yudaken 
Link: https://lore.kernel.org/r/20220907165152.994979-1-dylany@fb.com
Signed-off-by: Jens Axboe