NULL checks should be before the first dereference.

Spotted by the Coverity checker.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Ondrej Zajicek <santiago@crfreenet.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>