linux-kernel - Re: [PATCH 1/2] media: s5p-mfc: check for firmware allocation before requesting firmware

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Message-id: <5bbc048a-4b68-de23-373d-eb8a12c5b736@samsung.com>
Date:   Thu, 02 Nov 2017 09:12:43 +0100
From:   Andrzej Hajda <a.hajda@...sung.com>
To:     Shuah Khan <shuahkh@....samsung.com>, kyungmin.park@...sung.com,
        kamil@...as.org, jtp.park@...sung.com, mchehab@...nel.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] media: s5p-mfc: check for firmware allocation
 before requesting firmware

Hi Shuah,

On 06.10.2017 23:30, Shuah Khan wrote:
> Check if firmware is allocated before requesting firmware instead of
> requesting firmware only to release it if firmware is not allocated.
>
> Signed-off-by: Shuah Khan <shuahkh@....samsung.com>
> ---
>  drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c b/drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c
> index 69ef9c2..f064a0d1 100644
> --- a/drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c
> +++ b/drivers/media/platform/s5p-mfc/s5p_mfc_ctrl.c
> @@ -55,6 +55,11 @@ int s5p_mfc_load_firmware(struct s5p_mfc_dev *dev)
>  	 * into kernel. */
>  	mfc_debug_enter();
>  
> +	if (!dev->fw_buf.virt) {
> +		mfc_err("MFC firmware is not allocated\n");
> +		return -EINVAL;
> +	}
> +
>  	for (i = MFC_FW_MAX_VERSIONS - 1; i >= 0; i--) {
>  		if (!dev->variant->fw_name[i])
>  			continue;
> @@ -75,11 +80,6 @@ int s5p_mfc_load_firmware(struct s5p_mfc_dev *dev)
>  		release_firmware(fw_blob);
>  		return -ENOMEM;
>  	}
> -	if (!dev->fw_buf.virt) {
> -		mfc_err("MFC firmware is not allocated\n");
> -		release_firmware(fw_blob);
> -		return -EINVAL;
> -	}

Is there any scenario in which dev->fw_buf.virt is null and
s5p_mfc_load_firmware is called?
I suspect this check is not necessary at all.

Regards
Andrzej

>  	memcpy(dev->fw_buf.virt, fw_blob->data, fw_blob->size);
>  	wmb();
>  	release_firmware(fw_blob);