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

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

[Sasikantha babu]

1) Removed already created debug fs entries on failure

2) Fixed coding style 80 char per line

Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com>
---
 mm/memblock.c |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index a44eab3..5553723 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -966,11 +966,19 @@ static int __init memblock_init_debugfs(void)
 {
 	struct dentry *root = debugfs_create_dir("memblock", NULL);
 	if (!root)
-		return -ENXIO;
-	debugfs_create_file("memory", S_IRUGO, root, &memblock.memory, &memblock_debug_fops);
-	debugfs_create_file("reserved", S_IRUGO, root, &memblock.reserved, &memblock_debug_fops);
+		return -ENOMEM;
+
+	if (!debugfs_create_file("memory", S_IRUGO, root, &memblock.memory,
+				&memblock_debug_fops))
+		goto fail;
+	if (!debugfs_create_file("reserved", S_IRUGO, root, &memblock.reserved,
+				&memblock_debug_fops))
+		goto fail;
 
 	return 0;
+fail:
+	debugfs_remove_recursive(root);
+	return -ENOMEM;
 }
 __initcall(memblock_init_debugfs);
 
-- 
1.7.3.4

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

[Andrew Morton]

On Thu, 26 Apr 2012 01:29:52 +0530
Sasikantha babu <sasikanth.v19@gmail.com> wrote:

> 1) Removed already created debug fs entries on failure
> 
> 2) Fixed coding style 80 char per line
> 
> Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com>
> ---
>  mm/memblock.c |   14 +++++++++++---
>  1 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index a44eab3..5553723 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -966,11 +966,19 @@ static int __init memblock_init_debugfs(void)
>  {
>  	struct dentry *root = debugfs_create_dir("memblock", NULL);
>  	if (!root)
> -		return -ENXIO;
> -	debugfs_create_file("memory", S_IRUGO, root, &memblock.memory, &memblock_debug_fops);
> -	debugfs_create_file("reserved", S_IRUGO, root, &memblock.reserved, &memblock_debug_fops);
> +		return -ENOMEM;

hm, why the switch to -ENOMEM?

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.

> +	if (!debugfs_create_file("memory", S_IRUGO, root, &memblock.memory,
> +				&memblock_debug_fops))
> +		goto fail;
> +	if (!debugfs_create_file("reserved", S_IRUGO, root, &memblock.reserved,
> +				&memblock_debug_fops))
> +		goto fail;
>  
>  	return 0;
> +fail:
> +	debugfs_remove_recursive(root);
> +	return -ENOMEM;
>  }
>  __initcall(memblock_init_debugfs);

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

[Andrew Morton]

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.