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| author | Johannes Thumshirn <johannes.thumshirn@wdc.com> | 2020-02-14 00:24:30 +0900 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-03-23 17:01:39 +0100 |
| commit | c514c9b10bc1ec8b487e82900ab57f46a21956d9 (patch) | |
| tree | e4c6df21f5fd425c0d86a9599837aa4654db066a | |
| parent | f6d9abbc1f957f0fcf88d567ae2523d37d2731da (diff) | |
| download | linux-c514c9b10bc1ec8b487e82900ab57f46a21956d9.tar.bz2 | |
btrfs: don't kmap() pages from block devices
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>
| -rw-r--r-- | fs/btrfs/volumes.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 89be36a0fed6..00baa806662a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1249,7 +1249,6 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, void btrfs_release_disk_super(struct page *page) { - kunmap(page); put_page(page); } @@ -1277,10 +1276,10 @@ static int btrfs_read_disk_super(struct block_device *bdev, u64 bytenr, *page = read_cache_page_gfp(bdev->bd_inode->i_mapping, index, GFP_KERNEL); - if (IS_ERR_OR_NULL(*page)) + if (IS_ERR(*page)) return 1; - p = kmap(*page); + p = page_address(*page); /* align our pointer to the offset of the super block */ *disk_super = p + offset_in_page(bytenr); |