mm/dmapool.c: micro-optimisation remove unnecessary branch

Previously there was a check if 'size' is aligned to 'align' and if not
then it was aligned.  This check was expensive as both branch and division
are expensive instructions in most architectures.  'ALIGN' function on
already aligned value will not change it, and as it is cheaper than branch
+ division it can be executed all the time and branch can be removed.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200320173317.26408-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/dmapool.c b/mm/dmapool.c
index fe5d33060415bfcc4eb92e993b0a2b99f628a990..f9fb9bbd733e0fd20b2527999e5882e283184100 100644 (file)
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -144,9 +144,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev,
        else if (size < 4)
                size = 4;
 
-       if ((size % align) != 0)
-               size = ALIGN(size, align);
-
+       size = ALIGN(size, align);
        allocation = max_t(size_t, size, PAGE_SIZE);
 
        if (!boundary)