Ocfs2 devel - Apr 2010 - ocfs2: question about dlmfs_file_read()

Hello list,

I was looking through the code for something unrelated and I got
confused by this.

fs/ocfs2/dlmfs/dlmfs.c dlmfs_file_read()
   261          /* don't read past the lvb */
   262          if ((count + *ppos) > i_size_read(inode))
   263                  readlen = i_size_read(inode) - *ppos;
   264          else
   265                  readlen = count - *ppos;

	Shouldn't "readlen" just be "count" here?  What
prevents it from
	being a negative number?

   266
   267          lvb_buf = kmalloc(readlen, GFP_NOFS);

Anyway, this code has been around for a long time so I'm probably
missing something.  I was just curious.

regards,
dan carpenter

On Sun, Apr 18, 2010 at 10:32:01PM +0300, Dan Carpenter
wrote:
> Hello list,
> 
> I was looking through the code for something unrelated and I got
> confused by this.
> 
> fs/ocfs2/dlmfs/dlmfs.c dlmfs_file_read()
>    261          /* don't read past the lvb */
>    262          if ((count + *ppos) > i_size_read(inode))
>    263                  readlen = i_size_read(inode) - *ppos;
>    264          else
>    265                  readlen = count - *ppos;
> 
> 	Shouldn't "readlen" just be "count" here?  What
prevents it from
> 	being a negative number?
> 
>    266
>    267          lvb_buf = kmalloc(readlen, GFP_NOFS);
> 
> Anyway, this code has been around for a long time so I'm probably
> missing something.  I was just curious.
	No, I think you're right.  Mark, Sunil, anyone?

Joel

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Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127