Dan reported a smatch warning during potentential loss of info during
left shift if this code is compiled on 32bit systems.
New smatch warnings:
fs/fuse/dax.c:113 fuse_setup_one_mapping() warn: should 'start_idx << 21' be a
+64 bit type?
I ran smatch and found two more instances of similar warning. This patch
fixes all such instances.
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Vivek Goyal <[email protected]>
---
fs/fuse/dax.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
index ff99ab2a3c43..f06fdad3f7b1 100644
--- a/fs/fuse/dax.c
+++ b/fs/fuse/dax.c
@@ -186,7 +186,7 @@ static int fuse_setup_one_mapping(struct inode *inode, unsigned long start_idx,
struct fuse_conn_dax *fcd = fm->fc->dax;
struct fuse_inode *fi = get_fuse_inode(inode);
struct fuse_setupmapping_in inarg;
- loff_t offset = start_idx << FUSE_DAX_SHIFT;
+ loff_t offset = (loff_t)start_idx << FUSE_DAX_SHIFT;
FUSE_ARGS(args);
ssize_t err;
@@ -872,7 +872,7 @@ static int dmap_writeback_invalidate(struct inode *inode,
struct fuse_dax_mapping *dmap)
{
int ret;
- loff_t start_pos = dmap->itn.start << FUSE_DAX_SHIFT;
+ loff_t start_pos = (loff_t)dmap->itn.start << FUSE_DAX_SHIFT;
loff_t end_pos = (start_pos + FUSE_DAX_SZ - 1);
ret = filemap_fdatawrite_range(inode->i_mapping, start_pos, end_pos);
@@ -966,7 +966,7 @@ inode_inline_reclaim_one_dmap(struct fuse_conn_dax *fcd, struct inode *inode,
dmap = inode_lookup_first_dmap(inode);
if (dmap) {
start_idx = dmap->itn.start;
- dmap_start = start_idx << FUSE_DAX_SHIFT;
+ dmap_start = (u64)start_idx << FUSE_DAX_SHIFT;
dmap_end = dmap_start + FUSE_DAX_SZ - 1;
}
up_read(&fi->dax->sem);
@@ -1118,7 +1118,7 @@ static int lookup_and_reclaim_dmap(struct fuse_conn_dax *fcd,
{
int ret;
struct fuse_inode *fi = get_fuse_inode(inode);
- loff_t dmap_start = start_idx << FUSE_DAX_SHIFT;
+ loff_t dmap_start = (loff_t)start_idx << FUSE_DAX_SHIFT;
loff_t dmap_end = (dmap_start + FUSE_DAX_SZ) - 1;
down_write(&fi->i_mmap_sem);
--
2.25.4
* Vivek Goyal ([email protected]) wrote:
> Dan reported a smatch warning during potentential loss of info during
> left shift if this code is compiled on 32bit systems.
>
> New smatch warnings:
> fs/fuse/dax.c:113 fuse_setup_one_mapping() warn: should 'start_idx << 21' be a
> +64 bit type?
>
> I ran smatch and found two more instances of similar warning. This patch
> fixes all such instances.
>
> Reported-by: Dan Carpenter <[email protected]>
> Signed-off-by: Vivek Goyal <[email protected]>
> ---
> fs/fuse/dax.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/fuse/dax.c b/fs/fuse/dax.c
> index ff99ab2a3c43..f06fdad3f7b1 100644
> --- a/fs/fuse/dax.c
> +++ b/fs/fuse/dax.c
> @@ -186,7 +186,7 @@ static int fuse_setup_one_mapping(struct inode *inode, unsigned long start_idx,
> struct fuse_conn_dax *fcd = fm->fc->dax;
> struct fuse_inode *fi = get_fuse_inode(inode);
> struct fuse_setupmapping_in inarg;
> - loff_t offset = start_idx << FUSE_DAX_SHIFT;
> + loff_t offset = (loff_t)start_idx << FUSE_DAX_SHIFT;
I've not followed the others back, but isn't it easier to change
the start_idx parameter to be a loff_t, since the places it's called
from are poth loff_t pos?
Dave
> FUSE_ARGS(args);
> ssize_t err;
>
> @@ -872,7 +872,7 @@ static int dmap_writeback_invalidate(struct inode *inode,
> struct fuse_dax_mapping *dmap)
> {
> int ret;
> - loff_t start_pos = dmap->itn.start << FUSE_DAX_SHIFT;
> + loff_t start_pos = (loff_t)dmap->itn.start << FUSE_DAX_SHIFT;
> loff_t end_pos = (start_pos + FUSE_DAX_SZ - 1);
>
> ret = filemap_fdatawrite_range(inode->i_mapping, start_pos, end_pos);
> @@ -966,7 +966,7 @@ inode_inline_reclaim_one_dmap(struct fuse_conn_dax *fcd, struct inode *inode,
> dmap = inode_lookup_first_dmap(inode);
> if (dmap) {
> start_idx = dmap->itn.start;
> - dmap_start = start_idx << FUSE_DAX_SHIFT;
> + dmap_start = (u64)start_idx << FUSE_DAX_SHIFT;
> dmap_end = dmap_start + FUSE_DAX_SZ - 1;
> }
> up_read(&fi->dax->sem);
> @@ -1118,7 +1118,7 @@ static int lookup_and_reclaim_dmap(struct fuse_conn_dax *fcd,
> {
> int ret;
> struct fuse_inode *fi = get_fuse_inode(inode);
> - loff_t dmap_start = start_idx << FUSE_DAX_SHIFT;
> + loff_t dmap_start = (loff_t)start_idx << FUSE_DAX_SHIFT;
> loff_t dmap_end = (dmap_start + FUSE_DAX_SZ) - 1;
>
> down_write(&fi->i_mmap_sem);
> --
> 2.25.4
>
--
Dr. David Alan Gilbert / [email protected] / Manchester, UK
On Thu, May 06, 2021 at 08:07:39PM +0100, Dr. David Alan Gilbert wrote:
> > @@ -186,7 +186,7 @@ static int fuse_setup_one_mapping(struct inode *inode, unsigned long start_idx,
> > struct fuse_conn_dax *fcd = fm->fc->dax;
> > struct fuse_inode *fi = get_fuse_inode(inode);
> > struct fuse_setupmapping_in inarg;
> > - loff_t offset = start_idx << FUSE_DAX_SHIFT;
> > + loff_t offset = (loff_t)start_idx << FUSE_DAX_SHIFT;
>
> I've not followed the others back, but isn't it easier to change
> the start_idx parameter to be a loff_t, since the places it's called
> from are poth loff_t pos?
But an index isn't a file offset, and shouldn't be typed as such.
On Thu, May 06, 2021 at 12:35:17PM -0700, Matthew Wilcox wrote:
> On Thu, May 06, 2021 at 08:07:39PM +0100, Dr. David Alan Gilbert wrote:
> > > @@ -186,7 +186,7 @@ static int fuse_setup_one_mapping(struct inode *inode, unsigned long start_idx,
> > > struct fuse_conn_dax *fcd = fm->fc->dax;
> > > struct fuse_inode *fi = get_fuse_inode(inode);
> > > struct fuse_setupmapping_in inarg;
> > > - loff_t offset = start_idx << FUSE_DAX_SHIFT;
> > > + loff_t offset = (loff_t)start_idx << FUSE_DAX_SHIFT;
> >
> > I've not followed the others back, but isn't it easier to change
> > the start_idx parameter to be a loff_t, since the places it's called
> > from are poth loff_t pos?
>
> But an index isn't a file offset, and shouldn't be typed as such.
Agreed. This is index, so it seems better to not use "loff_t" to
represent it.
Vivek