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Subject[PATCH] mm,x86: fix span coverage in e820_all_mapped()
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@huawei.com>
---
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



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