From 252e5c6e2e5b4557599ef86ea5d02b0395e9056c Mon Sep 17 00:00:00 2001 From: zijun_hu Date: Fri, 7 Oct 2016 16:57:26 -0700 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 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 Cc: Tejun Heo Cc: Johannes Weiner Cc: Minchan Kim Cc: David Rientjes Signed-off-by: zijun_hu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/vmalloc.c') diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 91f44e78c516..80660a0f989b 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -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; -- cgit v1.2.3