linux-kernel - Re: [PATCH] mailbox: arm_mhuv2: clean up loop in get_irq_chan

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Message-ID: <20241114090146.u2cyg6fmykw57mei@vireshk-i7>
Date: Thu, 14 Nov 2024 14:31:46 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: Tushar Khandelwal <Tushar.Khandelwal@....com>,
	Jassi Brar <jassisinghbrar@...il.com>, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] mailbox: arm_mhuv2: clean up loop in get_irq_chan_comb()

On 14-11-24, 12:00, Dan Carpenter wrote:
> Both the inner and outer loops in this code use the "i" iterator.
> The inner loop should really use a different iterator.
> 
> It doesn't affect things in practice because the data comes from the
> device tree.  The "protocol" and "windows" variables are going to be
> zero.  That means we're always going to hit the "return &chans[channel];"
> statement and we're not going to want to iterate through the outer
> loop again.
> 
> Still it's worth fixing this for future use cases.
> 
> Fixes: 5a6338cce9f4 ("mailbox: arm_mhuv2: Add driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
> ---
>  drivers/mailbox/arm_mhuv2.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mailbox/arm_mhuv2.c b/drivers/mailbox/arm_mhuv2.c
> index 0ec21dcdbde7..cff7c343ee08 100644
> --- a/drivers/mailbox/arm_mhuv2.c
> +++ b/drivers/mailbox/arm_mhuv2.c
> @@ -500,7 +500,7 @@ static const struct mhuv2_protocol_ops mhuv2_data_transfer_ops = {
>  static struct mbox_chan *get_irq_chan_comb(struct mhuv2 *mhu, u32 __iomem *reg)
>  {
>  	struct mbox_chan *chans = mhu->mbox.chans;
> -	int channel = 0, i, offset = 0, windows, protocol, ch_wn;
> +	int channel = 0, i, j, offset = 0, windows, protocol, ch_wn;
>  	u32 stat;
>  
>  	for (i = 0; i < MHUV2_CMB_INT_ST_REG_CNT; i++) {
> @@ -510,9 +510,9 @@ static struct mbox_chan *get_irq_chan_comb(struct mhuv2 *mhu, u32 __iomem *reg)
>  
>  		ch_wn = i * MHUV2_STAT_BITS + __builtin_ctz(stat);
>  
> -		for (i = 0; i < mhu->length; i += 2) {
> -			protocol = mhu->protocols[i];
> -			windows = mhu->protocols[i + 1];
> +		for (j = 0; j < mhu->length; j += 2) {
> +			protocol = mhu->protocols[j];
> +			windows = mhu->protocols[j + 1];
>  
>  			if (ch_wn >= offset + windows) {
>  				if (protocol == DOORBELL)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh