diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2007-10-16 23:25:42 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-17 08:42:44 -0700 |
| commit | 3cb4f9fa0c5f3ded9f70f85b70ee6d429834f911 (patch) | |
| tree | d1f45445fa98bd41a2f8986781f7c62b470a6b8d /fs/ext2 | |
| parent | aa0dff2d09bfa50b7d02714a45920c64568e699d (diff) | |
| download | lwn-3cb4f9fa0c5f3ded9f70f85b70ee6d429834f911.tar.gz lwn-3cb4f9fa0c5f3ded9f70f85b70ee6d429834f911.zip | |
lib: percpu_counter_sub
Hugh spotted that some code does:
percpu_counter_add(&counter, -unsignedlong)
which, when the amount argument is of type s32, sort-of works thanks to
two's-complement. However when we'd change the type to s64 this breaks on 32bit
machines, because the promotion rules zero extend the unsigned number.
Provide percpu_counter_sub() to hide the s64 cast. That is:
percpu_counter_sub(&counter, foo)
is equal to:
percpu_counter_add(&counter, -(s64)foo);
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext2')
| -rw-r--r-- | fs/ext2/balloc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c index 53be25158560..9157fcf887bc 100644 --- a/fs/ext2/balloc.c +++ b/fs/ext2/balloc.c @@ -124,7 +124,7 @@ static int reserve_blocks(struct super_block *sb, int count) return 0; } - percpu_counter_add(&sbi->s_freeblocks_counter, -count); + percpu_counter_sub(&sbi->s_freeblocks_counter, count); sb->s_dirt = 1; return count; } |