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Commit 252e5c6e authored by zijun_hu's avatar zijun_hu Committed by Linus Torvalds
Browse files

mm/vmalloc.c: fix align value calculation error 

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: default avatarzijun_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: default avatarzijun_hu <zijun_hu@htc.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7c5f64f8

include/linux/bitops.h

+26 −10
Original line number Diff line number Diff line
@@ -65,16 +65,6 @@ static inline int get_bitmask_order(unsigned int count) 
	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)

{

	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
@@ -191,6 +181,32 @@ static inline unsigned fls_long(unsigned long 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

 * @word: The 64 bit word

mm/vmalloc.c

+4 −4
Original line number Diff line number Diff line
@@ -1359,14 +1359,14 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, 
	struct vm_struct *area;



	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);

	if (unlikely(!size))

		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);

	if (unlikely(!area))

		return NULL;