[v5,0/2] btrfs: Replace kmap() with kmap_local_page() in zstd.c

Message

Fabio M. De Francesco July 4, 2022, 3:23 p.m. UTC

This is a little series which serves the purpose to replace kmap() with
kmap_local_page() in btrfs/zstd.c. Actually this task is only accomplished
in patch 2/2.

Instead patch 1/2 is a pre-requisite for the above-mentioned replacement,
however, above all else, it has the purpose to conform the prototypes of
__kunmap_{local,atomic}() to their own correct semantics. Since those
functions don't make changes to the memory pointed by their arguments,
change the type of those arguments to become pointers to const void.

v4 -> v5: Use plain page_address() for pages which cannot come from Highmem
(instead of kmapping them); remove unnecessary initialisations to NULL
(thanks to Ira Weiny).

v3 -> v4: Resend and add linux-mm to the list of recipients (thanks to
Andrew Morton).

Fabio M. De Francesco (2):
  highmem: Make __kunmap_{local,atomic}() take "const void *"
  btrfs: Replace kmap() with kmap_local_page() in zstd.c

 arch/parisc/include/asm/cacheflush.h |  6 ++---
 arch/parisc/kernel/cache.c           |  2 +-
 fs/btrfs/zstd.c                      | 34 ++++++++++++----------------
 include/linux/highmem-internal.h     | 10 ++++----
 mm/highmem.c                         |  2 +-
 5 files changed, 24 insertions(+), 30 deletions(-)