buffer_head: remove redundant test from wait_on_buffer

The comment suggests that when b_count equals zero it is calling
__wait_no_buffer to trigger some debug, but as there is no debug in
__wait_on_buffer the whole thing is redundant.

AFAICT from the git log this has been the case for at least 5 years, so
it seems safe just to remove this.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 1b9ba19..2ce51fa 100644 (file)
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -314,15 +314,10 @@ map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block)
        bh->b_size = sb->s_blocksize;
 }
 
-/*
- * Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into
- * __wait_on_buffer() just to trip a debug check.  Because debug code in inline
- * functions is bloaty.
- */
 static inline void wait_on_buffer(struct buffer_head *bh)
 {
        might_sleep();
-       if (buffer_locked(bh) || atomic_read(&bh->b_count) == 0)
+       if (buffer_locked(bh))
                __wait_on_buffer(bh);
 }