Re: [PATCH] hwrng: ks-sa - fix runtime pm imbalance on error

[stern@xxxxxxxxxxxxxxxxxxx]

On Wed, May 20, 2020 at 03:42:17PM +0000, Sverdlin, Alexander (Nokia - DE/Ulm) wrote:
> Hello Dinghao,
> 
> On Wed, 2020-05-20 at 21:29 +0800, Dinghao Liu wrote:
> > pm_runtime_get_sync() increments the runtime PM usage counter even
> > the call returns an error code. Thus a pairing decrement is needed
> > on the error handling path to keep the counter balanced.
> 
> I believe, this is the wrong place for such kind of fix.
> pm_runtime_get_sync() has obviously a broken semantics with regards to
> your observation but no other driver does what you propose.

Look again.  For example, see what usb_autoresume_device() in 
drivers/usb/core/driver.c does.

You really shouldn't make generalizations such as "no other driver does 
..." unless you have read the code for every driver in the kernel.

Alan Stern