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Date:   Sat, 12 Jun 2021 21:55:46 -0500
From:   Bjorn Andersson <bjorn.andersson@linaro.org>
To:     Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc:     kvalo@codeaurora.org, wcn36xx@lists.infradead.org,
        linux-wireless@vger.kernel.org, shawn.guo@linaro.org,
        benl@squareup.com, loic.poulain@linaro.org
Subject: Re: [PATCH] wcn36xx: Move hal_buf allocation to devm_kmalloc in probe
Message-ID: <YMVzsh7CxGUmTprx@yoga>
References: <20210605173347.2266003-1-bryan.odonoghue@linaro.org>
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In-Reply-To: <20210605173347.2266003-1-bryan.odonoghue@linaro.org>
Precedence: bulk

On Sat 05 Jun 12:33 CDT 2021, Bryan O'Donoghue wrote:

> Right now wcn->hal_buf is allocated in wcn36xx_start(). This is a problem
> since we should have setup all of the buffers we required by the time
> ieee80211_register_hw() is called.
> 
> struct ieee80211_ops callbacks may run prior to mac_start() and therefore
> wcn->hal_buf must be initialized.
> 
> This is easily remediated by moving the allocation to probe() taking the
> opportunity to tidy up freeing memory by using devm_kmalloc().
> 
> Fixes: 8e84c2582169 ('wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680
> hardware')
> 

I don't think you're supposed to have an empty line between your Fixes
and S-o-b. That said, this looks good and your reasoning is sound.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> ---
>  drivers/net/wireless/ath/wcn36xx/main.c | 21 ++++++++-------------
>  1 file changed, 8 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/wcn36xx/main.c b/drivers/net/wireless/ath/wcn36xx/main.c
> index 84e117e0546c..2ccf7a8924a0 100644
> --- a/drivers/net/wireless/ath/wcn36xx/main.c
> +++ b/drivers/net/wireless/ath/wcn36xx/main.c
> @@ -296,23 +296,16 @@ static int wcn36xx_start(struct ieee80211_hw *hw)
>  		goto out_free_dxe_pool;
>  	}
>  
> -	wcn->hal_buf = kmalloc(WCN36XX_HAL_BUF_SIZE, GFP_KERNEL);
> -	if (!wcn->hal_buf) {
> -		wcn36xx_err("Failed to allocate smd buf\n");
> -		ret = -ENOMEM;
> -		goto out_free_dxe_ctl;
> -	}
> -
>  	ret = wcn36xx_smd_load_nv(wcn);
>  	if (ret) {
>  		wcn36xx_err("Failed to push NV to chip\n");
> -		goto out_free_smd_buf;
> +		goto out_free_dxe_ctl;
>  	}
>  
>  	ret = wcn36xx_smd_start(wcn);
>  	if (ret) {
>  		wcn36xx_err("Failed to start chip\n");
> -		goto out_free_smd_buf;
> +		goto out_free_dxe_ctl;
>  	}
>  
>  	if (!wcn36xx_is_fw_version(wcn, 1, 2, 2, 24)) {
> @@ -339,8 +332,6 @@ static int wcn36xx_start(struct ieee80211_hw *hw)
>  
>  out_smd_stop:
>  	wcn36xx_smd_stop(wcn);
> -out_free_smd_buf:
> -	kfree(wcn->hal_buf);
>  out_free_dxe_ctl:
>  	wcn36xx_dxe_free_ctl_blks(wcn);
>  out_free_dxe_pool:
> @@ -375,8 +366,6 @@ static void wcn36xx_stop(struct ieee80211_hw *hw)
>  
>  	wcn36xx_dxe_free_mem_pools(wcn);
>  	wcn36xx_dxe_free_ctl_blks(wcn);
> -
> -	kfree(wcn->hal_buf);
>  }
>  
>  static void wcn36xx_change_ps(struct wcn36xx *wcn, bool enable)
> @@ -1499,6 +1488,12 @@ static int wcn36xx_probe(struct platform_device *pdev)
>  	mutex_init(&wcn->hal_mutex);
>  	mutex_init(&wcn->scan_lock);
>  
> +	wcn->hal_buf = devm_kmalloc(wcn->dev, WCN36XX_HAL_BUF_SIZE, GFP_KERNEL);
> +	if (!wcn->hal_buf) {
> +		ret = -ENOMEM;
> +		goto out_wq;
> +	}
> +
>  	ret = dma_set_mask_and_coherent(wcn->dev, DMA_BIT_MASK(32));
>  	if (ret < 0) {
>  		wcn36xx_err("failed to set DMA mask: %d\n", ret);
> -- 
> 2.30.1
>