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| author | David Sterba <dsterba@suse.com> | 2020-07-01 20:45:04 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-12-08 15:53:57 +0100 |
| commit | ab108d992b1248adfb7c13c1136cab59c944a98c (patch) | |
| tree | 3632b276548fe4abb15b73d675bfcf2c27805b2c /fs/btrfs/ordered-data.c | |
| parent | e940e9a7c793e3fffe6cdef4f849d696c57ed3f7 (diff) | |
| download | lwn-ab108d992b1248adfb7c13c1136cab59c944a98c.tar.gz lwn-ab108d992b1248adfb7c13c1136cab59c944a98c.zip | |
btrfs: use precalculated sectorsize_bits from fs_info
We do a lot of calculations where we divide or multiply by sectorsize.
We also know and make sure that sectorsize is a power of two, so this
means all divisions can be turned to shifts and avoid eg. expensive
u64/u32 divisions.
The type is u32 as it's more register friendly on x86_64 compared to u8
and the resulting assembly is smaller (movzbl vs movl).
There's also superblock s_blocksize_bits but it's usually one more
pointer dereference farther than fs_info.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/ordered-data.c')
| -rw-r--r-- | fs/btrfs/ordered-data.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c index 87bac9ecdf4c..c6534daa40cd 100644 --- a/fs/btrfs/ordered-data.c +++ b/fs/btrfs/ordered-data.c @@ -868,7 +868,6 @@ int btrfs_find_ordered_sum(struct btrfs_inode *inode, u64 offset, struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree; unsigned long num_sectors; unsigned long i; - u32 sectorsize = btrfs_inode_sectorsize(inode); const u8 blocksize_bits = inode->vfs_inode.i_sb->s_blocksize_bits; const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); int index = 0; @@ -890,7 +889,7 @@ int btrfs_find_ordered_sum(struct btrfs_inode *inode, u64 offset, index += (int)num_sectors * csum_size; if (index == len) goto out; - disk_bytenr += num_sectors * sectorsize; + disk_bytenr += num_sectors * fs_info->sectorsize; } } out: |