[PATCH] fs/ntfs3: Remove unnecessary condition checking from ntfs_file_read_iter

[PATCH] fs/ntfs3: Remove unnecessary condition checking from ntfs_file_read_iter

[Kari Argillander]

This check will be also performed in generic_file_read_iter() so we do
not want to check this two times in a row.

This was founded with Smatch
	fs/ntfs3/file.c:803 ntfs_file_read_iter()
	warn: unused return: count = iov_iter_count()

Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
---
I cc Dan also because I am happy that I finally managed to install
Smack and straight away I found something with it. Thank you for
this great tool.

Next step is to integrate Smack to CI system. But will probanly take
a moment.
---
 fs/ntfs3/file.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index cb736701f2cc..5d41b84067ee 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -799,8 +799,6 @@ int ntfs3_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 
 static ssize_t ntfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
-	ssize_t err;
-	size_t count = iov_iter_count(iter);
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	struct ntfs_inode *ni = ntfs_i(inode);
@@ -829,9 +827,7 @@ static ssize_t ntfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 		return -EOPNOTSUPP;
 	}
 
-	err = count ? generic_file_read_iter(iocb, iter) : 0;
-
-	return err;
+	return generic_file_read_iter(iocb, iter);
 }
 
 /* returns array of locked pages */
-- 
2.30.2

Re: [PATCH] fs/ntfs3: Remove unnecessary condition checking from ntfs_file_read_iter

[Dan Carpenter]

On Wed, Aug 25, 2021 at 09:25:22PM +0300, Kari Argillander wrote:
> This check will be also performed in generic_file_read_iter() so we do
> not want to check this two times in a row.
> 
> This was founded with Smatch
> 	fs/ntfs3/file.c:803 ntfs_file_read_iter()
> 	warn: unused return: count = iov_iter_count()
> 
> Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
> ---
> I cc Dan also because I am happy that I finally managed to install
> Smack and straight away I found something with it. Thank you for
> this great tool.

Thanks!

You got a bit lucky, because you're using the --two-passes and the truth
is I haven't looked at that in years so I'm worried it's probably not
great.  You probably be better off not using the --two-passes option.  :/
I should remove it.

regards,
dan carpenter

Re: [PATCH] fs/ntfs3: Remove unnecessary condition checking from ntfs_file_read_iter

[Kari Argillander]

On Wed, Aug 25, 2021 at 10:17:57PM +0300, Dan Carpenter wrote:
> On Wed, Aug 25, 2021 at 09:25:22PM +0300, Kari Argillander wrote:
> > This check will be also performed in generic_file_read_iter() so we do
> > not want to check this two times in a row.
> > 
> > This was founded with Smatch
> > 	fs/ntfs3/file.c:803 ntfs_file_read_iter()
> > 	warn: unused return: count = iov_iter_count()
> > 
> > Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
> > ---
> > I cc Dan also because I am happy that I finally managed to install
> > Smack and straight away I found something with it. Thank you for
> > this great tool.
> 
> Thanks!
> 
> You got a bit lucky, because you're using the --two-passes and the truth
> is I haven't looked at that in years so I'm worried it's probably not
> great.  You probably be better off not using the --two-passes option.  :/
> I should remove it.

Haha no I need it :D I was just testing what this tool can do. I also
notice that --two-passes seems quite bad to read. But hey I found
something! :D Good to know that you are not using it. I will not use it
then. Thanks.

> 
> regards,
> dan carpenter
> 
> 

Re: [PATCH] fs/ntfs3: Remove unnecessary condition checking from ntfs_file_read_iter

[Konstantin Komarov]

On 25.08.2021 21:25, Kari Argillander wrote:
> This check will be also performed in generic_file_read_iter() so we do
> not want to check this two times in a row.
> 
> This was founded with Smatch
> 	fs/ntfs3/file.c:803 ntfs_file_read_iter()
> 	warn: unused return: count = iov_iter_count()
> 
> Signed-off-by: Kari Argillander <kari.argillander@gmail.com>
> ---
> I cc Dan also because I am happy that I finally managed to install
> Smack and straight away I found something with it. Thank you for
> this great tool.
> 
> Next step is to integrate Smack to CI system. But will probanly take
> a moment.
> ---
>  fs/ntfs3/file.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> index cb736701f2cc..5d41b84067ee 100644
> --- a/fs/ntfs3/file.c
> +++ b/fs/ntfs3/file.c
> @@ -799,8 +799,6 @@ int ntfs3_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
>  
>  static ssize_t ntfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
>  {
> -	ssize_t err;
> -	size_t count = iov_iter_count(iter);
>  	struct file *file = iocb->ki_filp;
>  	struct inode *inode = file->f_mapping->host;
>  	struct ntfs_inode *ni = ntfs_i(inode);
> @@ -829,9 +827,7 @@ static ssize_t ntfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
>  		return -EOPNOTSUPP;
>  	}
>  
> -	err = count ? generic_file_read_iter(iocb, iter) : 0;
> -
> -	return err;
> +	return generic_file_read_iter(iocb, iter);
>  }
>  
>  /* returns array of locked pages */
> 

Applied, thanks!