2023-04-13 04:00:22

by Jia Zhu

Subject: [PATCH] erofs: explicit cast blkaddr to u64 before shift operation

We should explicitly cast @blkaddr from u32 to u64 before the shift
operation to return the larger type.

Fixes: b1c2d99b18ff ("erofs: avoid hardcoded blocksize for subpage block support")
Signed-off-by: Jia Zhu <[email protected]>
---
fs/erofs/data.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index aa7f9e4f86fb..6fe9a779fa91 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -35,7 +35,7 @@ void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
enum erofs_kmap_type type)
{
struct inode *inode = buf->inode;
- erofs_off_t offset = blkaddr << inode->i_blkbits;
+ erofs_off_t offset = (erofs_off_t)blkaddr << inode->i_blkbits;
pgoff_t index = offset >> PAGE_SHIFT;
struct page *page = buf->page;
struct folio *folio;
--
2.20.1

2023-04-13 04:29:41

by Jingbo Xu

Subject: Re: [PATCH] erofs: explicit cast blkaddr to u64 before shift operation

On 4/13/23 11:57 AM, Jia Zhu wrote:
> We should explicitly cast @blkaddr from u32 to u64 before the shift
> operation to return the larger type.
>
> Fixes: b1c2d99b18ff ("erofs: avoid hardcoded blocksize for subpage block support")
> Signed-off-by: Jia Zhu <[email protected]>
> ---
> fs/erofs/data.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index aa7f9e4f86fb..6fe9a779fa91 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -35,7 +35,7 @@ void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
> enum erofs_kmap_type type)
> {
> struct inode *inode = buf->inode;
> - erofs_off_t offset = blkaddr << inode->i_blkbits;
> + erofs_off_t offset = (erofs_off_t)blkaddr << inode->i_blkbits;
> pgoff_t index = offset >> PAGE_SHIFT;
> struct page *page = buf->page;
> struct folio *folio;

LGTM. Thanks for catching this.

Reviewed-by: Jingbo Xu <[email protected]>

--
Thanks,
Jingbo

2023-04-13 04:52:32

by Gao Xiang

Subject: Re: [PATCH] erofs: explicit cast blkaddr to u64 before shift operation

On 2023/4/13 11:57, Jia Zhu wrote:
> We should explicitly cast @blkaddr from u32 to u64 before the shift
> operation to return the larger type.
>
> Fixes: b1c2d99b18ff ("erofs: avoid hardcoded blocksize for subpage block support")
> Signed-off-by: Jia Zhu <[email protected]>

Reviewed-by: Gao Xiang <[email protected]>

Let's fold it into the original patch.

Thanks,
Gao Xiang

> ---
> fs/erofs/data.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index aa7f9e4f86fb..6fe9a779fa91 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -35,7 +35,7 @@ void *erofs_bread(struct erofs_buf *buf, erofs_blk_t blkaddr,
> enum erofs_kmap_type type)
> {
> struct inode *inode = buf->inode;
> - erofs_off_t offset = blkaddr << inode->i_blkbits;
> + erofs_off_t offset = (erofs_off_t)blkaddr << inode->i_blkbits;
> pgoff_t index = offset >> PAGE_SHIFT;
> struct page *page = buf->page;
> struct folio *folio;