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mm/vmalloc.c: fix align value calculation error

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It causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags, for example
size=0x10000 -> fls_long(0x10000)=17 -> align=0x20000

get_count_order_long() is implemented and can be used instead of
fls_long() for fixing the bug, for example size=0x10000 ->
get_count_order_long(0x10000)=16 -> align=0x10000

[akpm@linux-foundation.org: s/get_order_long()/get_count_order_long()/]
[zijun_hu@zoho.com: fixes]
 Link: http://lkml.kernel.org/r/57AABC8B.1040409@zoho.com
[akpm@linux-foundation.org: locate get_count_order_long() next to get_count_order()]
[akpm@linux-foundation.org: move get_count_order[_long] definitions to pick up fls_long()]
[zijun_hu@htc.com: move out get_count_order[_long]() from __KERNEL__ scope]
 Link: http://lkml.kernel.org/r/57B2C4CE.80303@zoho.com
Link: http://lkml.kernel.org/r/fc045ecf-20fa-0722-b3ac-9a6140488fad@zoho.com
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
zijun_hu 2016-10-07 16:57:26 -07:00 • committed by Linus Torvalds
parent 7c5f64f844
commit 252e5c6e2e
2 changed files with 30 additions and 14 deletions
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36
include/linux/bitops.h
View file

@ -65,16 +65,6 @@ static inline int get_bitmask_order(unsigned int count)
return order; /* We could be slightly more clever with -1 here... */ return order; /* We could be slightly more clever with -1 here... */
} }
static inline int get_count_order(unsigned int count)
{
int order;
order = fls(count) - 1;
if (count & (count - 1))
order++;
return order;
}
static __always_inline unsigned long hweight_long(unsigned long w) static __always_inline unsigned long hweight_long(unsigned long w)
{ {
return sizeof(w) == 4 ? hweight32(w) : hweight64(w); return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
@ -191,6 +181,32 @@ static inline unsigned fls_long(unsigned long l)
return fls64(l); return fls64(l);
} }
static inline int get_count_order(unsigned int count)
{
int order;
order = fls(count) - 1;
if (count & (count - 1))
order++;
return order;
}
/**
* get_count_order_long - get order after rounding @l up to power of 2
* @l: parameter
*
* it is same as get_count_order() but with long type parameter
*/
static inline int get_count_order_long(unsigned long l)
{
if (l == 0UL)
return -1;
else if (l & (l - 1UL))
return (int)fls_long(l);
else
return (int)fls_long(l) - 1;
}
/** /**
* __ffs64 - find first set bit in a 64 bit word * __ffs64 - find first set bit in a 64 bit word
* @word: The 64 bit word * @word: The 64 bit word

8
mm/vmalloc.c
View file

@ -1359,14 +1359,14 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
struct vm_struct *area; struct vm_struct *area;
BUG_ON(in_interrupt()); BUG_ON(in_interrupt());
if (flags & VM_IOREMAP)
align = 1ul << clamp_t(int, fls_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
size = PAGE_ALIGN(size); size = PAGE_ALIGN(size);
if (unlikely(!size)) if (unlikely(!size))
return NULL; return NULL;
if (flags & VM_IOREMAP)
align = 1ul << clamp_t(int, get_count_order_long(size),
PAGE_SHIFT, IOREMAP_MAX_ORDER);
area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node); area = kzalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
if (unlikely(!area)) if (unlikely(!area))
return NULL; return NULL;