linux-kernel - Re: [PATCH] remoteproc: k3: Call of_node_put(rmem

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Message-ID: <666e3f5a-6b22-4530-b018-c194f33415b8@ti.com>
Date: Tue, 24 Sep 2024 10:29:35 -0500
From: Andrew Davis <afd@...com>
To: Markus Elfring <Markus.Elfring@....de>, <linux-remoteproc@...r.kernel.org>,
        Bjorn Andersson <andersson@...nel.org>, Hari Nagalla <hnagalla@...com>,
        Martyn Welch <martyn.welch@...labora.com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suman Anna <s-anna@...com>, Wadim Egorov <w.egorov@...tec.de>
CC: LKML <linux-kernel@...r.kernel.org>, <kernel-janitors@...r.kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Subject: Re: [PATCH] remoteproc: k3: Call of_node_put(rmem_np) only once in
 three functions

On 9/24/24 7:43 AM, Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Tue, 24 Sep 2024 14:28:35 +0200
> 
> An of_node_put(rmem_np) call was immediately used after a pointer check
> for a of_reserved_mem_lookup() call in three function implementations.
> Thus call such a function only once instead directly before the checks.
> 
> This issue was transformed by using the Coccinelle software.
> 

Quick check of all the users of of_reserved_mem_lookup(), they almost
all do the same thing, get the phandle, mem_lookup, then node_put.

Maybe a helper function like this:

struct reserved_mem *of_reserved_mem_region_lookup(const struct device_node *node, int index)
{
	struct device_node *np;
	struct reserved_mem *rmem;

	np = of_parse_phandle(node, "memory-region", index);
	if (!np)
		return ERR_PTR(-ENODEV);

	rmem = of_reserved_mem_lookup(np);
	of_node_put(np);
	if (!rmem)
		return ERR_PTR(-EINVAL);

	return rmem;
}

Added to of_reserved_mem.c would allow us to clean up these cases in
this patch, and then several more spots (and also help force standard
property name usage).

Andrew

> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>   drivers/remoteproc/ti_k3_dsp_remoteproc.c | 6 ++----
>   drivers/remoteproc/ti_k3_m4_remoteproc.c  | 6 ++----
>   drivers/remoteproc/ti_k3_r5_remoteproc.c  | 3 +--
>   3 files changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/remoteproc/ti_k3_dsp_remoteproc.c b/drivers/remoteproc/ti_k3_dsp_remoteproc.c
> index 8be3f631c192..d08a3a98ada1 100644
> --- a/drivers/remoteproc/ti_k3_dsp_remoteproc.c
> +++ b/drivers/remoteproc/ti_k3_dsp_remoteproc.c
> @@ -576,11 +576,9 @@ static int k3_dsp_reserved_mem_init(struct k3_dsp_rproc *kproc)
>   			return -EINVAL;
> 
>   		rmem = of_reserved_mem_lookup(rmem_np);
> -		if (!rmem) {
> -			of_node_put(rmem_np);
> -			return -EINVAL;
> -		}
>   		of_node_put(rmem_np);
> +		if (!rmem)
> +			return -EINVAL;
> 
>   		kproc->rmem[i].bus_addr = rmem->base;
>   		/* 64-bit address regions currently not supported */
> diff --git a/drivers/remoteproc/ti_k3_m4_remoteproc.c b/drivers/remoteproc/ti_k3_m4_remoteproc.c
> index 09f0484a90e1..a16fb165fced 100644
> --- a/drivers/remoteproc/ti_k3_m4_remoteproc.c
> +++ b/drivers/remoteproc/ti_k3_m4_remoteproc.c
> @@ -433,11 +433,9 @@ static int k3_m4_reserved_mem_init(struct k3_m4_rproc *kproc)
>   			return -EINVAL;
> 
>   		rmem = of_reserved_mem_lookup(rmem_np);
> -		if (!rmem) {
> -			of_node_put(rmem_np);
> -			return -EINVAL;
> -		}
>   		of_node_put(rmem_np);
> +		if (!rmem)
> +			return -EINVAL;
> 
>   		kproc->rmem[i].bus_addr = rmem->base;
>   		/* 64-bit address regions currently not supported */
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> index 747ee467da88..d0ebdd5cfa70 100644
> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> @@ -1001,12 +1001,11 @@ static int k3_r5_reserved_mem_init(struct k3_r5_rproc *kproc)
>   		}
> 
>   		rmem = of_reserved_mem_lookup(rmem_np);
> +		of_node_put(rmem_np);
>   		if (!rmem) {
> -			of_node_put(rmem_np);
>   			ret = -EINVAL;
>   			goto unmap_rmem;
>   		}
> -		of_node_put(rmem_np);
> 
>   		kproc->rmem[i].bus_addr = rmem->base;
>   		/*
> --
> 2.46.1
>