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SubjectRe: [PATCH v2] z3fold: fix the potential encode bug in encod_handle
Hi,  Vitaly

About the following patch, is it right?

Thanks
zhongjiang
On 2016/10/13 12:02, zhongjiang wrote:
> 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;
> }
>
> /*


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