The patch titled
Subject: mm/vmalloc.c: fix align value calculation error
has been added to the -mm tree. Its filename is
mm-vmalloc-fix-align-value-calculation-error.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vmalloc-fix-align-value-calculation-error.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vmalloc-fix-align-value-calculation-error.patch
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------------------------------------------------------
From: zijun_hu <zijun_hu@xxxxxxx>
Subject: mm/vmalloc.c: fix align value calculation error
It causes a doubled alignment requirement for __get_vm_area_node() if
parameter `size' is power of 2 and VM_IOREMAP is set in parameter flags
get_count_order_long() is implemented and used instead of fls_long() to
fix the bug
Link: http://lkml.kernel.org/r/fc045ecf-20fa-0722-b3ac-9a6140488fad@xxxxxxxx
Signed-off-by: zijun_hu <zijun_hu@xxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/bitops.h | 17 +++++++++++++++++
mm/vmalloc.c | 2 +-
2 files changed, 18 insertions(+), 1 deletion(-)
diff -puN include/linux/bitops.h~mm-vmalloc-fix-align-value-calculation-error include/linux/bitops.h
--- a/include/linux/bitops.h~mm-vmalloc-fix-align-value-calculation-error
+++ a/include/linux/bitops.h
@@ -192,6 +192,23 @@ static inline unsigned fls_long(unsigned
}
/**
+ * get_order_long - get order after rounding @l up to power of 2
+ * @l: parameter
+ *
+ * it is same as get_count_order() but long type parameter
+ * or 0 is returned if @l == 0UL
+ */
+static inline int get_order_long(unsigned long l)
+{
+ if (l == 0UL)
+ return 0;
+ else if (l & (l - 1UL))
+ return fls_long(l);
+ else
+ return fls_long(l) - 1;
+}
+
+/**
* __ffs64 - find first set bit in a 64 bit word
* @word: The 64 bit word
*
diff -puN mm/vmalloc.c~mm-vmalloc-fix-align-value-calculation-error mm/vmalloc.c
--- a/mm/vmalloc.c~mm-vmalloc-fix-align-value-calculation-error
+++ a/mm/vmalloc.c
@@ -1360,7 +1360,7 @@ static struct vm_struct *__get_vm_area_n
BUG_ON(in_interrupt());
if (flags & VM_IOREMAP)
- align = 1ul << clamp_t(int, fls_long(size),
+ align = 1ul << clamp_t(int, get_order_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
size = PAGE_ALIGN(size);
_
Patches currently in -mm which might be from zijun_hu@xxxxxxx are
mm-vmalloc-fix-align-value-calculation-error.patch
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