- 0 is not NULL
- use unlikely to hit the icache in isr more likely
- remove or comment empty if/else paths

[akpm@linux-foundation.org: build fix]
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>