Re: [RFC v4 06/21] ath10k: sdio support

["Valo, Kalle" <kvalo@qca.qualcomm.com>]

Erik Stromdahl <erik.stromdahl@gmail.com> writes:

> sdio/mailbox HIF implementation.
>
> Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>

I'm looking at this more carefully now and noticed this:

> +static int ath10k_sdio_bmi_credits(struct ath10k *ar)
> +{
> +	int ret;
> +	u32 addr, *cmd_credits;
> +	unsigned long timeout;
> +
> +	cmd_credits = kzalloc(sizeof(*cmd_credits), GFP_KERNEL);
> +	if (!cmd_credits) {
> +		ret = -ENOMEM;
> +		goto err;
> +	}
> +
> +	/* Read the counter register to get the command credits */
> +	addr = MBOX_COUNT_DEC_ADDRESS + ATH10K_HIF_MBOX_NUM_MAX * 4;
> +
> +	timeout = jiffies + BMI_COMMUNICATION_TIMEOUT_HZ;
> +	while (time_before(jiffies, timeout) && !*cmd_credits) {
> +		/* Hit the credit counter with a 4-byte access, the first byte
> +		 * read will hit the counter and cause a decrement, while the
> +		 * remaining 3 bytes has no effect. The rationale behind this
> +		 * is to make all HIF accesses 4-byte aligned.
> +		 */
> +		ret = ath10k_sdio_read_write_sync(ar, addr,
> +						  (u8 *)cmd_credits,
> +						  sizeof(*cmd_credits),
> +						  HIF_RD_SYNC_BYTE_INC);
> +		if (ret) {
> +			ath10k_warn(ar,
> +				    "Unable to decrement the command credit count register: %d\n",
> +				    ret);
> +			goto err_free;
> +		}
> +
> +		/* The counter is only 8 bits.
> +		 * Ignore anything in the upper 3 bytes
> +		 */
> +		*cmd_credits &= 0xFF;
> +	}
> +
> +	if (!*cmd_credits) {
> +		ath10k_warn(ar, "bmi communication timeout\n");
> +		ret = -ETIMEDOUT;
> +		goto err_free;
> +	}
> +
> +	return 0;
> +err_free:
> +	kfree(cmd_credits);
> +err:
> +	return ret;
> +}

AFAICS we are leaking cmd_credits if there's no error. Or is the buffer
freed somewhere within the mmc stack or something? The reason why I ask
is that I saw the same pattern in multiple functions so I'm curious.

-- 
Kalle Valo
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