Merge tag 'vfs-7.3-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull iomap updates from Christian Brauner:
 "The bulk of this is the conversion of iomap to a single ->iomap_next()
  callback and thus finishing the move to an iterator model.

  Every iomap operation drove its iteration through a struct iomap_ops
  holding ->iomap_begin() and ->iomap_end(). iomap_iter() only ever sees
  those as pointers. That means every step of every iteration is an
  indirect call.

  This collapses both into one ->iomap_next() callback that finishes the
  previous mapping and produces the next one. This lets callers inline
  the iteration loop and pass its ->iomap_next() as a compile time
  constant. That means the compiler can turn it into a direct and hence
  inlineable call.

  This also allows future callers to express custom logic to drive the
  iteration forward better. xfs, btrfs, ext4, ext2, erofs, f2fs, gfs2,
  hpfs, fuse, exfat, zonefs, ntfs, ntfs3 and the block device mapping
  are all converted. No functional changes are intended.

  This also adds a simple direct I/O path for small reads. On Gen5 NVMe
  the __iomap_dio_rw() dominates 4K random reads. The same single-core
  io_uring poll mode workload reaches ~3.2M IOPS against the raw block
  device but only ~1.92M through ext4 or XFS.

  __iomap_dio_rw(), iomap_iter(), iomap_dio_bio_iter() and kfree() were
  at the top of the profile. The new path is very lightweight if no
  special behavior is requested. The bio comes from a dedicated bioset
  and laid out so the whole request is a single cacheline aligned
  allocation. Completion runs inline.

  That takes ext4 from 1.92M to 2.19M IOPS in the original workload. fio
  shows around:
   - 4% at libaio queue depths of 64 and up
   - around 5% for io_uring
   - up to 10% for io_uring poll mode at depth 256
  on both ext4 and xfs.

  A few other patches:

   - iomap_folio_mark_uptodate() lets a filesystem that writes into the
     page cache outside the iomap read and write paths keep iomap's
     internal uptodate bitmap in sync, which fuse needs for
     server-pushed notify stores before it can enable large folios;

   - two fixes for iomap_bio_read_folio_range_sync(): a potential crash
     when device integrity behavior is changed and a missing
     bio_uninit().

   - a folio batch release fix on iomap callback failures

   - FGP_NOFS is dropped from iomap_get_folio()

   - documentation fix"

* tag 'vfs-7.3-rc1.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (29 commits)
  iomap: iomap_bio_read_folio_range_sync is missing a call to bio_uninit
  iomap: don't free integrity payload that doesn't exist
  docs: fix grammatical error in iomap docs
  exfat: convert iomap ops to ->iomap_next()
  fuse: convert iomap ops to ->iomap_next()
  hpfs: convert iomap ops to ->iomap_next()
  gfs2: convert iomap ops to ->iomap_next()
  f2fs: convert iomap ops to ->iomap_next()
  block: convert iomap ops to ->iomap_next()
  ext2: convert iomap ops to ->iomap_next()
  zonefs: convert iomap ops to ->iomap_next()
  erofs: convert iomap ops to ->iomap_next()
  ext4: convert iomap ops to ->iomap_next()
  ntfs: convert iomap ops to ->iomap_next()
  ntfs3: convert iomap ops to ->iomap_next()
  btrfs: convert iomap ops to ->iomap_next()
  xfs: convert iomap ops to ->iomap_next()
  iomap: add ->iomap_next()
  iomap: use GFP_NOWAIT when application for iomap_dio_simple allocations
  iomap: decouple simple direct I/O reads from iomap_dio_rw
  ...

diff --cc fs/erofs/zmap.c
Simple merge

diff --cc fs/exfat/iomap.c
Simple merge

diff --cc fs/fuse/file.c
Simple merge

diff --cc fs/iomap/bio.c
Simple merge

diff --cc fs/iomap/buffered-io.c
Simple merge

diff --cc fs/iomap/direct-io.c
Simple merge

diff --cc fs/ntfs3/inode.c
Simple merge

diff --cc include/linux/iomap.h
Simple merge