Re: [PATCH v10 06/22] IB/hns: Add initial cmd operation

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Wed, Jun 22, 2016 at 02:50:23PM +0800, Wei Hu (Xavier) wrote:
> 
> 
> On 2016/6/22 12:54, Leon Romanovsky wrote:
> >On Tue, Jun 21, 2016 at 09:01:57PM +0800, Wei Hu (Xavier) wrote:
> >>
> >>On 2016/6/21 19:28, Leon Romanovsky wrote:
> >>>On Tue, Jun 21, 2016 at 06:50:51PM +0800, Wei Hu (Xavier) wrote:
> >>>>On 2016/6/20 21:33, Leon Romanovsky wrote:
> >>>>>On Thu, Jun 16, 2016 at 10:35:14PM +0800, Lijun Ou wrote:
> >>>>>>This patch added the operation for cmd, and added some functions
> >>>>>>for initializing eq table and selecting cmd mode.
> >>>>>>
> >>>>>>Signed-off-by: Wei Hu <xavier.huwei-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
> >>>>>>Signed-off-by: Nenglong Zhao <zhaonenglong-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org>
> >>>>>>Signed-off-by: Lijun Ou <oulijun-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
> >>>>>>---
> >>>>>>PATCH v9/v8/v7/v6:
> >>>>>>- No change over the PATCH v5
> >>>>>>
> >>>>>>PATCH v5:
> >>>>>>- The initial patch which was redesigned based on the second patch
> >>>>>>   in PATCH v4
> >>>>>>---
> >>>>><...>
> >>>>>
> >>>>>>+#define CMD_MAX_NUM		32
> >>>>>>+
> >>>>>>+int hns_roce_cmd_init(struct hns_roce_dev *hr_dev)
> >>>>>>+{
> >>>>>>+	struct device *dev = &hr_dev->pdev->dev;
> >>>>>>+
> >>>>>>+	mutex_init(&hr_dev->cmd.hcr_mutex);
> >>>>>>+	sema_init(&hr_dev->cmd.poll_sem, 1);
> >>>>>>+	hr_dev->cmd.use_events = 0;
> >>>>>>+	hr_dev->cmd.toggle = 1;
> >>>>>>+	hr_dev->cmd.max_cmds = CMD_MAX_NUM;
> >>>>><...>
> >>>>>
> >>>>>>+	for (hr_cmd->token_mask = 1; hr_cmd->token_mask < hr_cmd->max_cmds;
> >>>>>>+	     hr_cmd->token_mask <<= 1)
> >>>>>>+		;
> >>>>>>+	--hr_cmd->token_mask;
> >>>>>It doesn't look that you dynamically change max_cmds supported.
> >>>>>Why do you need to calculate token_mask dynamically?
> >>>>Hi, Leon
> >>>>
> >>>>     1. The four lines above are in the function named
> >>>>hns_roce_cmd_use_events.
> >>>>          and now this function is only called once in hns_roce_probe.
> >>>>     2. In hns_roce_cmd_use_events,
> >>>>         we use these 4 lines to achieve the value of hr_cmd->token_mask
> >>>>according to hr_cmd->max_cmds dynamically,
> >>>>         then we only define one marco for hr_cmd->max_cmds as below:
> >>>>
> >>>>	#define CMD_MAX_NUM		32
> >>>>
> >>>>        And it looks more flexible.
> >>>It is called over engineering.
> >>>I would recommend to you to remove it.
> >>>
> >>>We don't need over complicated code which is executed
> >>>once with need to maintain with zero benefit.
> >>>
> >>>The other places need such simplification too.
> >>Hi, Leon
> >>
> >>         We will modify this place as below:
> >>         In hns_roce_hw_v1.c(for hip06 soc) file:
> >>
> >>             void hns_roce_v1_profile(struct hns_roce_dev *hr_dev)
> >>             {
> >>                 <snip>
> >>                 caps->max_cmds = 32;
> >>                 <snip>
> >>             }
> >>
> >>         In hns_roce_cmd.c file:
> >>
> >>   	  int hns_roce_cmd_init(struct hns_roce_dev *hr_dev)
> >>	  {
> >>	     <snip>
> >>	     hr_dev->cmd.max_cmds = hr_dev->caps->max_cmds;
> >>      		<snip>
> >>           }
> >>
> >>        Can you give more suggestions?
> >I would be happy to do it if I had enough time to review this code.
> >
> >General suggestion will be to ask yourself, if value is going to be
> >changed during the runtime. In case the answer is no, there is no room
> >to additional logic which translate constant to different value which
> >will be other constant.
> >
> >You should do it across all the patchset.
> >
> >So, in this specific case, the proposed change is not enough, you are
> >not solving an issue, but hiding it.
> >
> >Thanks
> We will modify this place as below：
> 
>     #define CMD_TOKEN_MASK      0x1f
> 
>    hr_cmd->token_mask = CMD_TOKEN_MASK;
> 
>    delete these four lines:
> 
> 	for (hr_cmd->token_mask = 1; hr_cmd->token_mask < hr_cmd->max_cmds;
> 	     hr_cmd->token_mask <<= 1)
> 		;
> 	--hr_cmd->token_mask;

Thanks,

While you are changing that file, please remove hns_roce_status_to_errno
function and embed it directly into hns_roce_cmd_event, so it will look
more compact.

	context->result = (status == HNS_ROCE_CMD_SUCCESS)?0:-EIO;

> 
>  	
> Thanks
> 
> >>
> >>Regards
> >>Wei Hu
> >>>>Regards
> >>>>Wei Hu
> >>>>
> >>>>
> >>>>
> >>
> 
> 

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