In the following case, e820_all_mapped() will return 1. A < start < B-1 and B < end < C, it means <start, end> spans two regions. <start, end>: [start - end] e820 addr: ...[A - B-1][B - C]... Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx> --- arch/x86/kernel/e820.c | 15 +++------------ 1 files changed, 3 insertions(+), 12 deletions(-) diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 174da5f..31ecab2 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -85,20 +85,11 @@ int __init e820_all_mapped(u64 start, u64 end, unsigned type) if (type && ei->type != type) continue; - /* is the region (part) in overlap with the current region ?*/ + /* is the region (part) in overlap with the current region ? */ if (ei->addr >= end || ei->addr + ei->size <= start) continue; - - /* if the region is at the beginning of <start,end> we move - * start to the end of the region since it's ok until there - */ - if (ei->addr <= start) - start = ei->addr + ei->size; - /* - * if start is now at or beyond end, we're done, full - * coverage - */ - if (start >= end) + /* is the region full coverage of <start, end> ? */ + if (ei->addr <= start && ei->addr + ei->size >= end) return 1; } return 0; -- 1.7.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>