[PATCH v3 0/5] iov_iter: Adjust styling/location of new splice functions

From: David Howells
Date: Tue Feb 14 2023 - 03:38:08 EST


Hi Jens, Al, Christoph,

Here are patches to make some changes that Christoph requested[1] to the
new generic file splice functions that I implemented[2]. Apart from one
functional change, they just altering the styling and move one of the
functions to a different file:

(1) Rename the main functions:

generic_file_buffered_splice_read() -> filemap_splice_read()
generic_file_direct_splice_read() -> direct_splice_read()

(2) Abstract out the calculation of the location of the head pipe buffer
into a helper function in linux/pipe_fs_i.h.

(3) Use init_sync_kiocb() in filemap_splice_read().

This is where the functional change is. Some kiocb fields are then
filled in where they were set to 0 before, including setting ki_flags
from f_iocb_flags.

(4) Move filemap_splice_read() to mm/filemap.c. filemap_get_pages() can
then be made static again.

(5) Fix splice-read for a number of filesystems that don't provide a
->read_folio() op and for which filemap_get_pages() cannot be used.

I've pushed the patches here also:

https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=iov-extract-3

I've also updated worked the changes into the commits on my iov-extract
branch if that would be preferable, though that means Jens would need to
update his for-6.3/iov-extract again.

David

Link: https://lore.kernel.org/r/Y+n0n2UE8BQa/OwW@xxxxxxxxxxxxx/ [1]
Link: https://lore.kernel.org/r/20230207171305.3716974-1-dhowells@xxxxxxxxxx/ [2]

Changes
=======
ver #3)
- Fix filesystems/drivers that don't have ->read_folio().

ver #2)
- Don't attempt to filter IOCB_* flags in filemap_splice_read().

Link: https://lore.kernel.org/r/20230213134619.2198965-1-dhowells@xxxxxxxxxx/ # v1

David Howells (5):
splice: Rename new splice functions
splice: Provide pipe_head_buf() helper
splice: Use init_sync_kiocb() in filemap_splice_read()
splice: Move filemap_read_splice() to mm/filemap.c
shmem, overlayfs, coda, tty, proc, kernfs, random: Fix splice-read

drivers/char/random.c | 4 +-
drivers/tty/tty_io.c | 4 +-
fs/coda/file.c | 36 +++++++++-
fs/kernfs/file.c | 2 +-
fs/overlayfs/file.c | 36 +++++++++-
fs/proc/inode.c | 4 +-
fs/proc/proc_sysctl.c | 2 +-
fs/proc_namespace.c | 6 +-
fs/splice.c | 146 ++------------------------------------
include/linux/fs.h | 6 ++
include/linux/pagemap.h | 2 -
include/linux/pipe_fs_i.h | 20 ++++++
mm/filemap.c | 136 +++++++++++++++++++++++++++++++++--
mm/internal.h | 6 ++
mm/shmem.c | 124 +++++++++++++++++++++++++++++++-
15 files changed, 373 insertions(+), 161 deletions(-)