Re: [PATCH 2/2] mm: memblock - Handled failure of debug fs entries creation

[Sasikanth babu <sasikanth.v19@gmail.com>]

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On Sun, Apr 29, 2012 at 12:36 AM, Andrew Morton
<akpm@linux-foundation.org>wrote:

> On Sun, 29 Apr 2012 00:32:26 +0530 Sasikanth babu <sasikanth.v19@gmail.com>
> wrote:
>
> > > Fact is, debugfs_create_dir() and debugfs_create_file() are stupid
> > > interfaces which don't provide the caller (and hence the user) with any
> > > information about why they failed.  Perhaps memblock_init_debugfs()
> > > should return -EWESUCK.
> > >
> >
> >    I'm working on a patch which address this issue. debugfs_create_XXX
> > calls
> >    will return proper error codes, and fixing the existing code not each
> > and every part  but the code
> >    which handles the values returned by debufs_create_XXX otherwise it
> will
> > break the existing
> >    functionality .
>
> Excellent!
>
> > (any suggestions or opinions ?)
>
> Well, don't modify the existing interfaces: create new ones and we can
> migrate gradually.  But you're probably already doing that.
>

  Not going to change the existing interface.  Modified debugfs_create_XXX
  to return ERR_PTR(error) instead of NULL.

[sasikantha@localhost linux-2.6]$ git diff
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index b80bc84..f5a5783 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -378,7 +378,7 @@ struct dentry *debugfs_create_file(const char *name,
umode_t mode,
        error = debugfs_create_by_name(name, mode, parent, &dentry,
                                       data, fops);
        if (error) {
-               dentry = NULL;
+               dentry = ERR_PTR(error);
                simple_release_fs(&debugfs_mount, &debugfs_mount_count);
                goto exit;
        }

  And from the caller side modifying the code as shown below (Currently
started doing
  modification for each subsystem)

        dir = debugfs_create_dir("test", NULL);

        if (IS_ERR(dir)) {
            return PTR_ERR(dir);
       }

   I think as you had mentioned creating new interface and migrating
gradually is the right of
   way of doing it.

   Thanks
   Sasi

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