From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Fri, 13 Feb 2015 22:36:08 +0000 (-0800)
Subject: lib: bitmap: remove redundant code from __bitmap_shift_right
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=97fb8e940bc56b157517c812c9c6cbfc83d48d78;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

lib: bitmap: remove redundant code from __bitmap_shift_right

If the condition k==lim-1 is true, we must have off == 0 (otherwise, k
could never become that big).  But in that case we have upper == 0 and
hence dst[k] == (src[k] & mask) >> rem.  Since mask consists of a
consecutive range of bits starting from the LSB, anding dst[k] with mask
is a no-op.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/lib/bitmap.c b/lib/bitmap.c
index a7a8bc02892d..761d2d4989ee 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -136,8 +136,6 @@ void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
 			lower &= mask;
 		lower >>= rem;
 		dst[k] = lower | upper;
-		if (left && k == lim - 1)
-			dst[k] &= mask;
 	}
 	if (off)
 		memset(&dst[lim - off], 0, off*sizeof(unsigned long));