From: Alexey Dobriyan <adobriyan@gmail.com>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] include/asm-*/bitops.h: fix masking in find_next_zero_bit()
Date: Tue, 24 Jan 2006 00:05:52 +0300 [thread overview]
Message-ID: <20060123210552.GA12531@mipter.zuzino.mipt.ru> (raw)
Commit 3960f2faaf0a67ad352bd5d4085e43f19f33ab91 says:
[PATCH] m68knommu: fix find_next_zero_bit in bitops.h
We're starting a number of big applications (memory footprint app.
1MByte) on our Arcturus uC5272. Therefore memory fragmentation is a
real pain for us. We've switched to uClinux-2.4.27-uc1 and found that
page_alloc2 fragments the memory heavily.
Digging into it we found a bug in the find_next_zero_bit function in the
m68knommu/bitops.h file. if the size isn't a multiple of 32 than the
upper bits of the last word to be searched should be masked. But the
functions masks the lower bits of the last word because it uses a right
shift instead of a left shift operator.
Fix same typos.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
include/asm-cris/bitops.h | 2 +-
include/asm-frv/bitops.h | 2 +-
include/asm-h8300/bitops.h | 2 +-
include/asm-v850/bitops.h | 2 +-
4 files changed, 4 insertions(+), 4 deletions(-)
--- a/include/asm-cris/bitops.h
+++ b/include/asm-cris/bitops.h
@@ -290,7 +290,7 @@ static inline int find_next_zero_bit (co
tmp = *p;
found_first:
- tmp |= ~0UL >> size;
+ tmp |= ~0UL << size;
found_middle:
return result + ffz(tmp);
}
--- a/include/asm-frv/bitops.h
+++ b/include/asm-frv/bitops.h
@@ -209,7 +209,7 @@ static inline int find_next_zero_bit(con
tmp = *p;
found_first:
- tmp |= ~0UL >> size;
+ tmp |= ~0UL << size;
found_middle:
return result + ffz(tmp);
}
--- a/include/asm-h8300/bitops.h
+++ b/include/asm-h8300/bitops.h
@@ -227,7 +227,7 @@ static __inline__ int find_next_zero_bit
tmp = *p;
found_first:
- tmp |= ~0UL >> size;
+ tmp |= ~0UL << size;
found_middle:
return result + ffz(tmp);
}
--- a/include/asm-v850/bitops.h
+++ b/include/asm-v850/bitops.h
@@ -188,7 +188,7 @@ static inline int find_next_zero_bit(con
tmp = *p;
found_first:
- tmp |= ~0UL >> size;
+ tmp |= ~0UL << size;
found_middle:
return result + ffz (tmp);
}
reply other threads:[~2006-01-23 20:48 UTC|newest]
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