Re: [PATCH v1 1/1] serial: 8250_port: Drop duplicate NULL check

[Andy Shevchenko]

On Tue, Mar 03, 2026 at 09:55:45AM +0200, Andy Shevchenko wrote:
> On Tue, Mar 03, 2026 at 06:25:29AM +0100, Jiri Slaby wrote:
> > On 02. 03. 26, 16:27, Andy Shevchenko wrote:
> > > serial8250_release_dma() is NULL-aware, no need to check this in the caller.
> > > While at it, make sure DMA won't be used again, by NULLifying the pointer.

...

> > > -	if (up->dma)
> > > -		serial8250_release_dma(up);
> > > +	serial8250_release_dma(up);
> > > +	up->dma = NULL;
> > 
> > Shouldn't serial8250_release_dma() NULL it instead, so the callers need not
> > to bother?
> 
> I copied what 8250_omap is doing. But we can do what you suggested I think.

I looked at the 8250_dma code and serial8250_release_dma() in particular,
and I think I am not going to change the approach. The 'dma' pointer is
assigned outside of serial8250_request_dma() and NULLifying it in
serial8250_release_dma() will be a layering violation.

-- 
With Best Regards,
Andy Shevchenko