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

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

Posted by Vasily Averin 3 years, 11 months ago

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 <vvs@openvz.org>
---
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

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

Posted by Matthew Wilcox 3 years, 11 months ago

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));

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

Posted by Vasily Averin 3 years, 11 months ago

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 <vvs@openvz.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
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

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

Posted by Christian Brauner 3 years, 11 months ago

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 <vvs@openvz.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---

Looks good to me,
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>

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

Posted by Matthew Wilcox 3 years, 11 months ago

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 <vvs@openvz.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

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

Posted by Christoph Hellwig 3 years, 11 months ago

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>