linux-kernel - Re: [PATCH 2/2] rpmsg: glink: Consolidate TX_DATA and TX_DATA

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Message-ID: <e01c0579-5ce2-459b-0306-7351f8aca561@quicinc.com>
Date:   Fri, 7 Apr 2023 15:10:45 -0700
From:   Chris Lew <quic_clew@...cinc.com>
To:     Bjorn Andersson <quic_bjorande@...cinc.com>,
        Bjorn Andersson <andersson@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>
CC:     <linux-arm-msm@...r.kernel.org>,
        <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] rpmsg: glink: Consolidate TX_DATA and TX_DATA_CONT



On 3/27/2023 7:41 AM, Bjorn Andersson wrote:
> Rather than duplicating most of the code for constructing the initial
> TX_DATA and subsequent TX_DATA_CONT packets, roll them into a single
> loop.
> 
> Signed-off-by: Bjorn Andersson <quic_bjorande@...cinc.com>
> ---
>   drivers/rpmsg/qcom_glink_native.c | 46 +++++++++----------------------
>   1 file changed, 13 insertions(+), 33 deletions(-)
> 
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index 62634d020d13..082cf7f4888e 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -1309,7 +1309,7 @@ static int __qcom_glink_send(struct glink_channel *channel,
>   	int ret;
>   	unsigned long flags;
>   	int chunk_size = len;
> -	int left_size = 0;
> +	size_t offset = 0;
>   
>   	if (!glink->intentless) {
>   		while (!intent) {
> @@ -1343,49 +1343,29 @@ static int __qcom_glink_send(struct glink_channel *channel,
>   		iid = intent->id;
>   	}
>   
> -	if (wait && chunk_size > SZ_8K) {
> -		chunk_size = SZ_8K;
> -		left_size = len - chunk_size;
> -	}
> -	req.msg.cmd = cpu_to_le16(GLINK_CMD_TX_DATA);
> -	req.msg.param1 = cpu_to_le16(channel->lcid);
> -	req.msg.param2 = cpu_to_le32(iid);
> -	req.chunk_size = cpu_to_le32(chunk_size);
> -	req.left_size = cpu_to_le32(left_size);
> -
> -	ret = qcom_glink_tx(glink, &req, sizeof(req), data, chunk_size, wait);
> -
> -	/* Mark intent available if we failed */
> -	if (ret) {
> -		if (intent)
> -			intent->in_use = false;
> -		return ret;
> -	}
> -
> -	while (left_size > 0) {
> -		data = (void *)((char *)data + chunk_size);
> -		chunk_size = left_size;
> -		if (chunk_size > SZ_8K)
> +	while (offset < len) {
> +		chunk_size = len - offset;
> +		if (chunk_size > SZ_8K && (wait || offset > 0))

offset > 0 seems to be a new condition compared to the previous logic.
Are we adding this as a cached check because we know if offset is set 
then fragmented sends are allowed?

I don't think wait would have changed during the loop, so I'm not sure 
if offset > 0 is adding any extra value to the check.

>   			chunk_size = SZ_8K;
> -		left_size -= chunk_size;
>   
> -		req.msg.cmd = cpu_to_le16(GLINK_CMD_TX_DATA_CONT);
> +		req.msg.cmd = cpu_to_le16(offset == 0 ? GLINK_CMD_TX_DATA : GLINK_CMD_TX_DATA_CONT);
>   		req.msg.param1 = cpu_to_le16(channel->lcid);
>   		req.msg.param2 = cpu_to_le32(iid);
>   		req.chunk_size = cpu_to_le32(chunk_size);
> -		req.left_size = cpu_to_le32(left_size);
> +		req.left_size = cpu_to_le32(len - offset - chunk_size);
>   
> -		ret = qcom_glink_tx(glink, &req, sizeof(req), data,
> -				    chunk_size, wait);
> -
> -		/* Mark intent available if we failed */
> +		ret = qcom_glink_tx(glink, &req, sizeof(req), data + offset, chunk_size, wait);
>   		if (ret) {
> +			/* Mark intent available if we failed */
>   			if (intent)
>   				intent->in_use = false;
> -			break;
> +			return ret;
>   		}
> +
> +		offset += chunk_size;
>   	}
> -	return ret;
> +
> +	return 0;
>   }
>   
>   static int qcom_glink_send(struct rpmsg_endpoint *ept, void *data, int len)