linux.git/lib/iov_iter.c, branch v6.8-rc2

Merge tag 'vfs-6.8.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2024-01-08T19:43:04+00:00

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()

iov_iter: replace import_single_range() with import_ubuf()

2023-12-05T10:57:37+00:00

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

iov_iter: remove unused 'iov' argument from import_single_range()

2023-12-05T10:57:34+00:00

It is entirely unused, just get rid of it.

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

iov_iter: fix copy_page_to_iter_nofault()

2023-11-18T15:42:07+00:00

The recent conversion to inline functions made two mistakes:

1. It tries to copy the full amount requested (bytes), not just what's
   available in the kmap'd page (n).
2. It's not applying the offset in the first page.

Note that copy_page_to_iter_nofault() is only used by /proc/kcore. This
was detected by drgn's test suite.

Fixes: f1982740f5e7 ("iov_iter: Convert iterate*() to inline funcs")
Signed-off-by: Omar Sandoval 
Link: https://lore.kernel.org/r/c1616e06b5248013cbbb1881bb4fef85a7a69ccb.1700257019.git.osandov@fb.com
Acked-by: David Howells 
Signed-off-by: Christian Brauner

iov_iter, net: Move hash_and_copy_to_iter() to net/

2023-10-09T07:35:14+00:00

Move hash_and_copy_to_iter() to be with its only caller in networking code.

Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/20230925120309.1731676-13-dhowells@redhat.com
cc: Alexander Viro 
cc: Jens Axboe 
cc: Christoph Hellwig 
cc: Christian Brauner 
cc: Matthew Wilcox 
cc: Linus Torvalds 
cc: David Laight 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: netdev@vger.kernel.org
Signed-off-by: Christian Brauner

iov_iter, net: Move csum_and_copy_to/from_iter() to net/

2023-10-09T07:35:14+00:00

Move csum_and_copy_to/from_iter() to net code now that the iteration
framework can be #included.

Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/20230925120309.1731676-10-dhowells@redhat.com
cc: Alexander Viro 
cc: Jens Axboe 
cc: Christoph Hellwig 
cc: Christian Brauner 
cc: Matthew Wilcox 
cc: Linus Torvalds 
cc: David Laight 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: netdev@vger.kernel.org
Signed-off-by: Christian Brauner

iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc()

2023-10-09T07:35:14+00:00

iter->copy_mc is only used with a bvec iterator and only by
dump_emit_page() in fs/coredump.c so rather than handle this in
memcpy_from_iter_mc() where it is checked repeatedly by _copy_from_iter()
and copy_page_from_iter_atomic(),

Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/20230925120309.1731676-9-dhowells@redhat.com
cc: Alexander Viro 
cc: Jens Axboe 
cc: Christoph Hellwig 
cc: Christian Brauner 
cc: Matthew Wilcox 
cc: Linus Torvalds 
cc: David Laight 
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Christian Brauner

iov_iter: Convert iterate*() to inline funcs

2023-09-25T12:30:28+00:00

Convert the iov_iter iteration macros to inline functions to make the code
easier to follow.

The functions are marked __always_inline as we don't want to end up with
indirect calls in the code.  This, however, leaves dealing with ->copy_mc
in an awkard situation since the step function (memcpy_from_iter_mc())
needs to test the flag in the iterator, but isn't passed the iterator.
This will be dealt with in a follow-up patch.

The variable names in the per-type iterator functions have been harmonised
as much as possible and made clearer as to the variable purpose.

The iterator functions are also moved to a header file so that other
operations that need to scan over an iterator can be added.  For instance,
the rbd driver could use this to scan a buffer to see if it is all zeros
and libceph could use this to generate a crc.

Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/3710261.1691764329@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/855.1692047347@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/20230816120741.534415-1-dhowells@redhat.com/ # v3
Link: https://lore.kernel.org/r/20230925120309.1731676-8-dhowells@redhat.com
cc: Alexander Viro 
cc: Jens Axboe 
cc: Christoph Hellwig 
cc: Christian Brauner 
cc: Matthew Wilcox 
cc: Linus Torvalds 
cc: David Laight 
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Christian Brauner

iov_iter: Derive user-backedness from the iterator type

2023-09-25T12:30:28+00:00

Use the iterator type to determine whether an iterator is user-backed or
not rather than using a special flag for it.  Now that ITER_UBUF and
ITER_IOVEC are 0 and 1, they can be checked with a single comparison.

Signed-off-by: David Howells 
Link: https://lore.kernel.org/r/20230925120309.1731676-7-dhowells@redhat.com
cc: Alexander Viro 
cc: Jens Axboe 
cc: Christoph Hellwig 
cc: Christian Brauner 
cc: Matthew Wilcox 
cc: Linus Torvalds 
cc: David Laight 
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Christian Brauner

iov_iter: Fix iov_iter_extract_pages() with zero-sized entries

2023-09-09T22:11:49+00:00

iov_iter_extract_pages() doesn't correctly handle skipping over initial
zero-length entries in ITER_KVEC and ITER_BVEC-type iterators.

The problem is that it accidentally reduces maxsize to 0 when it
skipping and thus runs to the end of the array and returns 0.

Fix this by sticking the calculated size-to-copy in a new variable
rather than back in maxsize.

Fixes: 7d58fe731028 ("iov_iter: Add a function to extract a page list from an iterator")
Signed-off-by: David Howells 
Reviewed-by: Christoph Hellwig 
Cc: Christian Brauner 
Cc: Jens Axboe 
Cc: Al Viro 
Cc: David Hildenbrand 
Cc: John Hubbard 
Signed-off-by: Linus Torvalds