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

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Message-ID: <104da4a2-a099-666e-b821-e8efe0901ce8@foss.st.com>
Date:   Wed, 22 Mar 2023 09:21:14 +0100
From:   Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
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 3/21/23 22:32, Mathieu Poirier wrote:
> 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.

My apologize, I misread the of_phandle_iterator_next function. you can forget my
comment.

Regards,
Arnaud

> 
>> This one remains valid.
>> reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
>>
> 
> Ok
> 
>> Thanks,
>> Arnaud
>>
>>
>>>  
>>>  		rproc_add_carveout(rproc, mem);
>>>  		index++;