The first kiocb_set_cancel_fn() argument may point at a struct kiocb
that is not embedded inside struct aio_kiocb. With the current code,
depending on the compiler, the req->ki_ctx read happens either before
the IOCB_AIO_RW test or after that test. Move the req->ki_ctx read such
that it is guaranteed that the IOCB_AIO_RW test happens first.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Cc: Benjamin LaHaise <ben@communityfibre.ca>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Fixes: b820de741ae4 ("fs/aio: Restrict kiocb_set_cancel_fn() to I/O submitted via libaio")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240304235715.3790858-1-bvanassche@acm.org
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Patch "fs/aio: Make io_cancel() generate completions again" is based on the
assumption that calling kiocb->ki_cancel() does not complete R/W requests.
This is incorrect: the two drivers that call kiocb_set_cancel_fn() callers
set a cancellation function that calls usb_ep_dequeue(). According to its
documentation, usb_ep_dequeue() calls the completion routine with status
-ECONNRESET. Hence this revert.

Cc: Benjamin LaHaise <ben@communityfibre.ca>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Reported-by: syzbot+b91eb2ed18f599dd3c31@syzkaller.appspotmail.com
Fixes: 54cbc058d86b ("fs/aio: Make io_cancel() generate completions again")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240304182945.3646109-1-bvanassche@acm.org
Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

The following patch accidentally removed the code for delivering
completions for cancelled reads and writes to user space: "[PATCH 04/33]
aio: remove retry-based AIO"
(https://lore.kernel.org/all/1363883754-27966-5-git-send-email-koverstreet@google.com/)
>From that patch:

-	if (kiocbIsCancelled(iocb)) {
-		ret = -EINTR;
-		aio_complete(iocb, ret, 0);
-		/* must not access the iocb after this */
-		goto out;
-	}

This leads to a leak in user space of a struct iocb. Hence this patch
that restores the code that reports to user space that a read or write
has been cancelled successfully.

Fixes: 41003a7bcfed ("aio: remove retry-based AIO")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240215204739.2677806-3-bvanassche@acm.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

If kiocb_set_cancel_fn() is called for I/O submitted via io_uring, the
following kernel warning appears:

WARNING: CPU: 3 PID: 368 at fs/aio.c:598 kiocb_set_cancel_fn+0x9c/0xa8
Call trace:
 kiocb_set_cancel_fn+0x9c/0xa8
 ffs_epfile_read_iter+0x144/0x1d0
 io_read+0x19c/0x498
 io_issue_sqe+0x118/0x27c
 io_submit_sqes+0x25c/0x5fc
 __arm64_sys_io_uring_enter+0x104/0xab0
 invoke_syscall+0x58/0x11c
 el0_svc_common+0xb4/0xf4
 do_el0_svc+0x2c/0xb0
 el0_svc+0x2c/0xa4
 el0t_64_sync_handler+0x68/0xb4
 el0t_64_sync+0x1a4/0x1a8

Fix this by setting the IOCB_AIO_RW flag for read and write I/O that is
submitted by libaio.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Sandeep Dhavale <dhavale@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: stable@vger.kernel.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240215204739.2677806-2-bvanassche@acm.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Pull sysctl updates from Luis Chamberlain:
 "To help make the move of sysctls out of kernel/sysctl.c not incur a
  size penalty sysctl has been changed to allow us to not require the
  sentinel, the final empty element on the sysctl array. Joel Granados
  has been doing all this work.

  In the v6.6 kernel we got the major infrastructure changes required to
  support this. For v6.7 we had all arch/ and drivers/ modified to
  remove the sentinel. For v6.8-rc1 we get a few more updates for fs/
  directory only.

  The kernel/ directory is left but we'll save that for v6.9-rc1 as
  those patches are still being reviewed. After that we then can expect
  also the removal of the no longer needed check for procname == NULL.

  Let us recap the purpose of this work:

   - this helps reduce the overall build time size of the kernel and run
     time memory consumed by the kernel by about ~64 bytes per array

   - the extra 64-byte penalty is no longer inncurred now when we move
     sysctls out from kernel/sysctl.c to their own files

  Thomas Weißschuh also sent a few cleanups, for v6.9-rc1 we expect to
  see further work by Thomas Weißschuh with the constificatin of the
  struct ctl_table.

  Due to Joel Granados's work, and to help bring in new blood, I have
  suggested for him to become a maintainer and he's accepted. So for
  v6.9-rc1 I look forward to seeing him sent you a pull request for
  further sysctl changes. This also removes Iurii Zaikin as a maintainer
  as he has moved on to other projects and has had no time to help at
  all"

* tag 'sysctl-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  sysctl: remove struct ctl_path
  sysctl: delete unused define SYSCTL_PERM_EMPTY_DIR
  coda: Remove the now superfluous sentinel elements from ctl_table array
  sysctl: Remove the now superfluous sentinel elements from ctl_table array
  fs: Remove the now superfluous sentinel elements from ctl_table array
  cachefiles: Remove the now superfluous sentinel element from ctl_table array
  sysclt: Clarify the results of selftest run
  sysctl: Add a selftest for handling empty dirs
  sysctl: Fix out of bounds access for empty sysctl registers
  MAINTAINERS: Add Joel Granados as co-maintainer for proc sysctl
  MAINTAINERS: remove Iurii Zaikin from proc sysctl

Pull vfs iov_iter cleanups from Christian Brauner:
 "This contains a minor cleanup. The patches drop an unused argument
  from import_single_range() allowing to replace import_single_range()
  with import_ubuf() and dropping import_single_range() completely"

* tag 'vfs-6.8.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iov_iter: replace import_single_range() with import_ubuf()
  iov_iter: remove unused 'iov' argument from import_single_range()

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel elements ctl_table struct. Special attention was placed in
making sure that an empty directory for fs/verity was created when
CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not defined. In this case we use the
register sysctl call that expects a size.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

With the removal of the 'iov' argument to import_single_range(), the two
functions are now fully identical. Convert the import_single_range()
callers to import_ubuf(), and remove the former fully.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20231204174827.1258875-3-axboe@kernel.dk
Signed-off-by: Christian Brauner <brauner@kernel.org>

It is entirely unused, just get rid of it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20231204174827.1258875-2-axboe@kernel.dk
Signed-off-by: Christian Brauner <brauner@kernel.org>

I've been observing workloads where IPIs due to wakeups in
aio_complete() are ~15% of total CPU time in the profile. Most of those
wakeups are unnecessary when completion batching is in use in
io_getevents().

This plumbs min_nr through via the wait eventry, so that aio_complete()
can avoid doing unnecessary wakeups.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Link: https://lore.kernel.org/r/20231122234257.179390-1-kent.overstreet@linux.dev
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: <linux-aio@kvack.org>
Cc: <linux-fsdevel@vger.kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>