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[084/133] s390/bitops: fix find_next_bit_left

Message ID 1376692475-28413-85-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Aug. 16, 2013, 10:33 p.m. UTC 
3.8.13.7 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

commit 3b0040a47ad63f7147e9e7d2febb61a3b564bb90 upstream.

The find_next_bit_left function is broken if used with an offset which
is not a multiple of 64. The shift to mask the bits of a 64-bit word
not to search is in the wrong direction, the result can be either a
bit found smaller than the offset or failure to find a set bit.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 arch/s390/include/asm/bitops.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h
index 1542293..787eb3b 100644
--- a/arch/s390/include/asm/bitops.h
+++ b/arch/s390/include/asm/bitops.h
@@ -698,7 +698,7 @@  static inline int find_next_bit_left(const unsigned long *addr,
 	size -= offset;
 	p = addr + offset / __BITOPS_WORDSIZE;
 	if (bit) {
-		set = __flo_word(0, *p & (~0UL << bit));
+		set = __flo_word(0, *p & (~0UL >> bit));
 		if (set >= size)
 			return size + offset;
 		if (set < __BITOPS_WORDSIZE)