2022-05-23 06:06:12

by Vasily Averin

Subject: [PATCH v3] fs/proc/base.c: fix incorrect fmode_t casts

Fixes sparce warnings:
fs/proc/base.c:2240:25: sparse: warning: cast to restricted fmode_t
fs/proc/base.c:2297:42: sparse: warning: cast from restricted fmode_t
fs/proc/base.c:2394:48: sparse: warning: cast from restricted fmode_t

fmode_t is birwie type and requires __force attribute for any cast

Signed-off-by: Vasily Averin <[email protected]>
---
v3: split, reworked according to Christoph Hellwig recommendation
---
fs/proc/base.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index c1031843cc6a..4e4edf9db5f0 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2237,13 +2237,13 @@ static struct dentry *
proc_map_files_instantiate(struct dentry *dentry,
struct task_struct *task, const void *ptr)
{
- fmode_t mode = (fmode_t)(unsigned long)ptr;
+ const fmode_t *mode = ptr;
struct proc_inode *ei;
struct inode *inode;

inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
- ((mode & FMODE_READ ) ? S_IRUSR : 0) |
- ((mode & FMODE_WRITE) ? S_IWUSR : 0));
+ ((*mode & FMODE_READ ) ? S_IRUSR : 0) |
+ ((*mode & FMODE_WRITE) ? S_IWUSR : 0));
if (!inode)
return ERR_PTR(-ENOENT);

@@ -2294,7 +2294,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,

if (vma->vm_file)
result = proc_map_files_instantiate(dentry, task,
- (void *)(unsigned long)vma->vm_file->f_mode);
+ &vma->vm_file->f_mode);

out_no_vma:
mmap_read_unlock(mm);
@@ -2391,7 +2391,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
buf, len,
proc_map_files_instantiate,
task,
- (void *)(unsigned long)p->mode))
+ &p->mode))
break;
ctx->pos++;
}
--
2.36.1

2022-05-23 07:34:45

by Matthew Wilcox

Subject: Re: [PATCH v3] fs/proc/base.c: fix incorrect fmode_t casts

On Sun, May 22, 2022 at 03:08:42PM +0300, Vasily Averin wrote:
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index c1031843cc6a..4e4edf9db5f0 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2237,13 +2237,13 @@ static struct dentry *
> proc_map_files_instantiate(struct dentry *dentry,
> struct task_struct *task, const void *ptr)
> {
> - fmode_t mode = (fmode_t)(unsigned long)ptr;
> + const fmode_t *mode = ptr;

Why not ...

fmode_t mode = *(fmode_t *)ptr;

and then you don't need

> - ((mode & FMODE_READ ) ? S_IRUSR : 0) |
> - ((mode & FMODE_WRITE) ? S_IWUSR : 0));
> + ((*mode & FMODE_READ ) ? S_IRUSR : 0) |
> + ((*mode & FMODE_WRITE) ? S_IWUSR : 0));

2022-05-23 08:14:16

by Vasily Averin

Subject: [PATCH v4] fs/proc/base.c: fix incorrect fmode_t casts

Fixes sparce warnings:
fs/proc/base.c:2240:25: sparse: warning: cast to restricted fmode_t
fs/proc/base.c:2297:42: sparse: warning: cast from restricted fmode_t
fs/proc/base.c:2394:48: sparse: warning: cast from restricted fmode_t

fmode_t is birwie type and requires __force attribute for any cast

Signed-off-by: Vasily Averin <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
v4: improved according to Matthew Wilcox's hint
v3: split, reworked according to Christoph Hellwig recommendation
---
fs/proc/base.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index c1031843cc6a..89521d3fc456 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2237,7 +2237,7 @@ static struct dentry *
proc_map_files_instantiate(struct dentry *dentry,
struct task_struct *task, const void *ptr)
{
- fmode_t mode = (fmode_t)(unsigned long)ptr;
+ fmode_t mode = *(fmode_t *)ptr;
struct proc_inode *ei;
struct inode *inode;

@@ -2294,7 +2294,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,

if (vma->vm_file)
result = proc_map_files_instantiate(dentry, task,
- (void *)(unsigned long)vma->vm_file->f_mode);
+ &vma->vm_file->f_mode);

out_no_vma:
mmap_read_unlock(mm);
@@ -2391,7 +2391,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
buf, len,
proc_map_files_instantiate,
task,
- (void *)(unsigned long)p->mode))
+ &p->mode))
break;
ctx->pos++;
}
--
2.36.1

2022-05-23 09:49:48

by Christian Brauner

Subject: Re: [PATCH v4] fs/proc/base.c: fix incorrect fmode_t casts

On Mon, May 23, 2022 at 06:37:29AM +0300, Vasily Averin wrote:
> Fixes sparce warnings:
> fs/proc/base.c:2240:25: sparse: warning: cast to restricted fmode_t
> fs/proc/base.c:2297:42: sparse: warning: cast from restricted fmode_t
> fs/proc/base.c:2394:48: sparse: warning: cast from restricted fmode_t
>
> fmode_t is birwie type and requires __force attribute for any cast
>
> Signed-off-by: Vasily Averin <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>
> ---

Looks good to me,
Reviewed-by: Christian Brauner (Microsoft) <[email protected]>