Re: [PATCH 1/1] backing-dev: refactor wb_congested_put()

[Jules Irenge]

On Wed, 11 Mar 2020, Andrew Morton wrote:

> On Wed, 11 Mar 2020 19:29:48 -0700 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> 
> > On Wed, Mar 11, 2020 at 05:59:19PM -0700, Andrew Morton wrote:
> > > hm, it's hard to get excited over this.  Open-coding the
> > > refcount_dec_and_lock_irqsave() internals at a callsite in order to
> > > make sparse happy.
> > > 
> > > Is there some other way, using __acquires (for example)?
> > 
> > sparse is really bad at conditional lock acquisition. 
> 
> I can well imagine.
> 
> > we have similar
> > problems over the vfs.  but we shouldn't be obfuscating our code to make
> > the tool happy.
> 
> Perhaps sparse needs a way of being directed to suppress checking
> across a particular function.
> 
> 
Thanks for the feedback, maybe this is a limitation for Sparse.

I have experienced quite often this problem.