linux-kernel - Re: [PATCH 1/5] remoteproc: stm32: Call of_node

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Message-ID: <20230321213250.GB2782856@p14s>
Date:   Tue, 21 Mar 2023 15:32:50 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>
Cc:     andersson@...nel.org, shawnguo@...nel.org, s.hauer@...gutronix.de,
        kernel@...gutronix.de, festevam@...il.com, linux-imx@....com,
        patrice.chotard@...s.st.com, mcoquelin.stm32@...il.com,
        alexandre.torgue@...s.st.com, arnaud.pouliquen@...com,
        hongxing.zhu@....com, peng.fan@....com, shengjiu.wang@....com,
        linux-remoteproc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/5] remoteproc: stm32: Call of_node_put() on iteration
 error

On Tue, Mar 21, 2023 at 10:00:03AM +0100, Arnaud POULIQUEN wrote:
> Hi Mathieu,
> 
> On 3/20/23 23:18, Mathieu Poirier wrote:
> > Function of_phandle_iterator_next() calls of_node_put() on the last
> > device_node it iterated over, but when the loop exits prematurely it has
> > to be called explicitly> 
> > Fixes: 13140de09cc2 ("remoteproc: stm32: add an ST stm32_rproc driver")
> > Cc: stable@...r.kernel.org
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> > ---
> >  drivers/remoteproc/stm32_rproc.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
> > index 7d782ed9e589..23c1690b8d73 100644
> > --- a/drivers/remoteproc/stm32_rproc.c
> > +++ b/drivers/remoteproc/stm32_rproc.c
> > @@ -223,11 +223,13 @@ static int stm32_rproc_prepare(struct rproc *rproc)
> >  	while (of_phandle_iterator_next(&it) == 0) {
> >  		rmem = of_reserved_mem_lookup(it.node);
> >  		if (!rmem) {
> > +			of_node_put(it.node);
> >  			dev_err(dev, "unable to acquire memory-region\n");
> >  			return -EINVAL;
> >  		}
> >  
> >  		if (stm32_rproc_pa_to_da(rproc, rmem->base, &da) < 0) {
> > +			of_node_put(it.node);
> >  			dev_err(dev, "memory region not valid %pa\n",
> >  				&rmem->base);
> >  			return -EINVAL;
> > @@ -254,8 +256,10 @@ static int stm32_rproc_prepare(struct rproc *rproc)
> >  							   it.node->name);
> >  		}
> >  
> > -		if (!mem)
> > +		if (!mem) {
> > +			of_node_put(it.node);
> >  			return -ENOMEM;
> > +		}
> 
> Good catch!
> 
> Looking in code I don't see that we call of_node_put() when we release the
> carveouts. 
> Please tell me if I'm wrong but look to me that we should also call of_node_put()
> in mem->release() op, in drivers. 
>

Are you referring to entry->release(), which for stm32 is
stm32_rproc_mem_release(), in rproc_resource_cleanup()?

If so then no, it is not needed since of_phandle_iterator_next() calls
of_node_put() on the previous device_node with each iteration.

Otherwise I fail to understand the question and will ask you to clarify.

> This one remains valid.
> reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
> 

Ok

> Thanks,
> Arnaud
> 
> 
> >  
> >  		rproc_add_carveout(rproc, mem);
> >  		index++;