mm/vmalloc.c: fix align value calculation error (252e5c6e) · Commits · 戴 / test

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>

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;

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