From: zijun_hu <zijun_hu@xxxxxxx> Subject: 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 used instead of fls_long() for fixing the bug, for example size=0x10000 -> get_count_order_long(0x10000)=16 -> align=0x10000 [akpm@xxxxxxxxxxxxxxxxxxxx: s/get_order_long()/get_count_order_long()/] [zijun_hu@xxxxxxxx: fixes] Link: http://lkml.kernel.org/r/57AABC8B.1040409@xxxxxxxx [akpm@xxxxxxxxxxxxxxxxxxxx: locate get_count_order_long() next to get_count_order()] [akpm@xxxxxxxxxxxxxxxxxxxx: move get_count_order[_long] definitions to pick up fls_long()] [zijun_hu@xxxxxxx: move out get_count_order[_long]() from __KERNEL__ scope] Link: http://lkml.kernel.org/r/57B2C4CE.80303@xxxxxxxx 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: zijun_hu <zijun_hu@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/bitops.h | 36 ++++++++++++++++++++++++++---------- mm/vmalloc.c | 8 ++++---- 2 files changed, 30 insertions(+), 14 deletions(-) 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 @@ -65,16 +65,6 @@ static inline int get_bitmask_order(unsi 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 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 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 @@ -1359,14 +1359,14 @@ static struct vm_struct *__get_vm_area_n 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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
