linux-kernel - Re: [v2] ath6kl: Use vmalloc to allocate ar->fw for api1 method

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Date:	Wed, 02 Dec 2015 05:20:33 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Brent Taylor <motobud@...il.com>
Cc:	kvalo@....qualcomm.com, linux-wireless@...r.kernel.org,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	ath6kl@...ts.infradead.org
Subject: Re: [v2] ath6kl: Use vmalloc to allocate ar->fw for api1 method

On Tue, 2015-12-01 at 22:18 -0600, Brent Taylor wrote:
> Since commit 8437754c8335 ("ath6kl: Use vmalloc instead of kmalloc for
> fw") ar->fw is expected to be pointing to memory allocated by vmalloc.
> If the api1 method (via ath6kl_fetch_fw_api1) is used to allocate memory
> for ar->fw, then kmemdup is used.  This patch checks if the firmware being
> loaded is the 'fw' image, then use vmalloc, otherwise use kmalloc.
> 
> Signed-off-by: Brent Taylor <motobud@...il.com>
> ---
> v2: Fix commit message and code formatting (use tab instaed of spaces)
> 
>  drivers/net/wireless/ath/ath6kl/init.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ath/ath6kl/init.c b/drivers/net/wireless/ath/ath6kl/init.c
> index 6ae0734..4f16bd8 100644
> --- a/drivers/net/wireless/ath/ath6kl/init.c
> +++ b/drivers/net/wireless/ath/ath6kl/init.c
> @@ -673,10 +673,15 @@ static int ath6kl_get_fw(struct ath6kl *ar, const char *filename,
>  		return ret;
>  
>  	*fw_len = fw_entry->size;
> -	*fw = kmemdup(fw_entry->data, fw_entry->size, GFP_KERNEL);
> +	if (&ar->fw == fw)
> +		*fw = vmalloc(fw_entry->size);
> +	else
> +		*fw = kmalloc(fw_entry->size, GFP_KERNEL);
>  
>  	if (*fw == NULL)
>  		ret = -ENOMEM;
> +	else
> +		memcpy(*fw, fw_entry->data, fw_entry->size);
>  
>  	release_firmware(fw_entry);
>  

This looks very odd.

Why not using kvfree() in ath6kl_core_cleanup() ?

If you switch to vmalloc() here because the kmemdup() was potentially
failing, then the changelog should say it !

Using vmalloc() instead of kmalloc() should be driven by the allocation
size, not the legacy code doing the freeing.



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