Re: [PATCH] dma: cpp41: Fix handling of error path

[Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>]

* Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> [161114 06:59]:
> On Mon, Nov 14, 2016 at 06:47:31AM -0800, Tony Lindgren wrote:
> > Hi,
> > 
> > * Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> [161114 06:35]:
> > > On Fri, Nov 11, 2016 at 11:28:52AM -0800, Tony Lindgren wrote:
> > > > If we return early on pm_runtime_get() error, we need to also call
> > > > pm_runtime_put_noidle() as pointed out in a musb related thread
> > > > by Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>. This is to keep the PM runtime
> > > > use counts happy.
> > > > 
> > > > Fixes: fdea2d09b997 ("dmaengine: cppi41: Add basic PM runtime support")
> > > > Cc: Johan Hovold <johan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> > > > Signed-off-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
> > > > ---
> > > >  drivers/dma/cppi41.c | 11 +++++++++--
> > > >  1 file changed, 9 insertions(+), 2 deletions(-)
> > >  
> > > > @@ -466,6 +472,7 @@ static void cppi41_dma_issue_pending(struct dma_chan *chan)
> > > >  
> > > >  	error = pm_runtime_get(cdd->ddev.dev);
> > > >  	if ((error != -EINPROGRESS) && error < 0) {
> > > > +		pm_runtime_put_noidle(cdd->ddev.dev);
> > > >  		dev_err(cdd->ddev.dev, "Failed to pm_runtime_get: %i\n",
> > > >  			error);
> > > 
> > > Will this chunk not introduce rather than fix an imbalance, though? An
> > > error is never returned above, and the corresponding put is done
> > > unconditionally as far as I can tell.
> > 
> > There is already an early return in cppi41_dma_issue_pending() on
> > error.
> 
> Indeed, but before
> 
> 	"dma: cppi41: Fix unpaired pm runtime when only a USB hub is
>         connected"
> 
> from last week, the corresponding put in cppi41_irq() was done
> unconditionally and would have required an unconditional get here.

Oh yeah that's right as the pm_runtime_mark_last_busy() and
pm_runtime_put_autosuspend() got moved.

Regards,

Tony
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