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[v6,0/2] btrfs: Replace kmap() with kmap_local_page() in zstd.c

Message ID 20220706111520.12858-1-fmdefrancesco@gmail.com (mailing list archive)
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Series btrfs: Replace kmap() with kmap_local_page() in zstd.c | expand

Message

Fabio M. De Francesco July 6, 2022, 11:15 a.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.

v5 -> v6: Delete an unnecessary assignment in 2/2 (thanks to Ira Weiny).

v4 -> v5: Use plain page_address() for pages which cannot come from Highmem
(instead of kmapping them); remove unnecessary initializations to NULL
in 2/2 (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                      | 33 +++++++++++-----------------
 include/linux/highmem-internal.h     | 10 ++++-----
 mm/highmem.c                         |  2 +-
 5 files changed, 23 insertions(+), 30 deletions(-)

Comments

David Sterba July 7, 2022, 10:12 p.m. UTC | #1
On Wed, Jul 06, 2022 at 01:15:18PM +0200, Fabio M. De Francesco wrote:
> 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.
> 
> v5 -> v6: Delete an unnecessary assignment in 2/2 (thanks to Ira Weiny).
> 
> v4 -> v5: Use plain page_address() for pages which cannot come from Highmem
> (instead of kmapping them); remove unnecessary initializations to NULL
> in 2/2 (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

Added to the kmap patch queue, thanks. With all the other conversion
there are 5 patches

  highmem: Make __kunmap_{local,atomic}() take const void pointer
  btrfs: zstd: replace kmap() with kmap_local_page()
  btrfs: zlib: replace kmap() with kmap_local_page() in zlib_compress_pages()
  btrfs: zlib: replace kmap() with kmap_local_page() in zlib_decompress_bio()
  btrfs: replace kmap_atomic() with kmap_local_page()

and there are no kmap or kmap_atomic left in fs/btrfs, scheduled for 5.20.