btrfs: don't kmap() pages from block devices

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Block device mappings are never in highmem so kmap() / kunmap() calls for
pages from block devices are unneeded. Use page_address() instead of
kmap() to get to the virtual addreses.

While we're at it, read_cache_page_gfp() doesn't return NULL on error,
only an ERR_PTR, so use IS_ERR() to check for errors.

Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Johannes Thumshirn 2020-02-14 00:24:30 +09:00 • committed by David Sterba

parent f6d9abbc1f

commit c514c9b10b

1 changed files with 2 additions and 3 deletions

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fs/btrfs/volumes.c

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