lkml.org 
[lkml]   [2016]   [Oct]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] z3fold: fix the potential encode bug in encod_handle
Date
From: zhong jiang <zhongjiang@huawei.com>

At present, zhdr->first_num plus bud can exceed the BUDDY_MASK
in encode_handle, it will lead to the the caller handle_to_buddy
return the error value.

The patch fix the issue by changing the BUDDY_MASK to PAGE_MASK,
it will be consistent with handle_to_z3fold_header. At the same time,
change the BUDDY_MASK to PAGE_MASK in handle_to_buddy is better.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
---
mm/z3fold.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 8f9e89c..e8fc216 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -169,7 +169,7 @@ static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud)

handle = (unsigned long)zhdr;
if (bud != HEADLESS)
- handle += (bud + zhdr->first_num) & BUDDY_MASK;
+ handle += (bud + zhdr->first_num) & PAGE_MASK;
return handle;
}

@@ -183,7 +183,7 @@ static struct z3fold_header *handle_to_z3fold_header(unsigned long handle)
static enum buddy handle_to_buddy(unsigned long handle)
{
struct z3fold_header *zhdr = handle_to_z3fold_header(handle);
- return (handle - zhdr->first_num) & BUDDY_MASK;
+ return (handle - zhdr->first_num) & PAGE_MASK;
}

/*
--
1.8.3.1
\
 
 \ /
  Last update: 2016-10-13 06:04    [W:0.082 / U:17.704 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site