Re: [PATCH v1 3/4] dmaengine: Add a comment on why it's okay when kasprintf() fails

[Andy Shevchenko]

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