In dma_request_chan() one of the kasprintf() call is not checked
against NULL. This is completely fine right now, but make others
aware of this aspect by adding a comment.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dmaengine.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index c1357d7f3dc6..dd4224d90f07 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -854,8 +854,8 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
 
 found:
 #ifdef CONFIG_DEBUG_FS
-	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
-					  name);
+	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev), name);
+	/* No functional issue if it fails, users are supposed to test before use */
 #endif
 
 	chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
-- 
2.43.0.rc1.1336.g36b5255a03ac

On Mon, Oct 07, 2024 at 06:06:47PM +0300, Andy Shevchenko wrote:
> In dma_request_chan() one of the kasprintf() call is not checked
> against NULL. This is completely fine right now, but make others
> aware of this aspect by adding a comment.

suggest:

Add comment in dma_request_chan() to clarify kasprintf() missing return
value check and it is correct funcationaly.

>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/dma/dmaengine.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index c1357d7f3dc6..dd4224d90f07 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -854,8 +854,8 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
>
>  found:
>  #ifdef CONFIG_DEBUG_FS
> -	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
> -					  name);
> +	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev), name);
> +	/* No functional issue if it fails, users are supposed to test before use */

comments should above chan->dbg_client_name ...

No funcational issue if it is NULL because user always test it before use.

>  #endif
>
>  	chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
> --
> 2.43.0.rc1.1336.g36b5255a03ac
>

On Mon, Oct 07, 2024 at 11:51:14AM -0400, Frank Li wrote:
> On Mon, Oct 07, 2024 at 06:06:47PM +0300, Andy Shevchenko wrote:
> > In dma_request_chan() one of the kasprintf() call is not checked
> > against NULL. This is completely fine right now, but make others
> > aware of this aspect by adding a comment.
> 
> suggest:
> 
> Add comment in dma_request_chan() to clarify kasprintf() missing return
> value check and it is correct funcationaly.

Sure, thanks.

...

> >  #ifdef CONFIG_DEBUG_FS
> > -	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
> > -					  name);
> > +	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev), name);
> > +	/* No functional issue if it fails, users are supposed to test before use */
> 
> comments should above chan->dbg_client_name ...

It's placed exactly there on purpose. Because it explains 

> No funcational issue if it is NULL because user always test it before use.

I think my is better because it reveals the actual issue, ideally users
must not rely on that and the code here should assign a valid pointer.
The problem is that the code paths are a bit twisted and I only can come
up with this comment _for now_. Semantically this change is a band-aid
(and not good), but at least it describes current (broken) desing.

-- 
With Best Regards,
Andy Shevchenko