Re: [ndctl patch 3/4] query_fw_finish_status: get rid of redundant variable

[Ira Weiny <ira.weiny@intel.com>]

On Mon, Oct 28, 2019 at 03:37:48PM -0400, Jeff Moyer wrote:
> Ira Weiny <ira.weiny@intel.com> writes:
> 
> >> (Watching the unit test run fall into an infinite loop..) Nope, the
> >> break is in the switch scope, the while loop needs the 'goto out'.
> >> 
> >> Yes this bit definitely needs to be refactored :)
> >
> > How about this patch instead?  Untested.
> 
> I'm not a fan of the looping with gotos.

Me either... But... the logic here is not the same.

>
> I think separating out the
> waiting for busy to its own function would make this more clear.
> Looking more closely, there are other issues.  The timeout code looks at
> the seconds, but ignores the fractions, so you could be off by almost an
> entire second, there.

For this operation that is probably not a big deal.  We should be waiting much
longer than the operation should take anyway.

>
> It also doens't retry the sleep if interrupted.

This could be an issue.

> Finally, I find the variables names to be highly confusing.
> 
> I've decided not to fix those last two bugs just yet, but here's a patch
> that shows the dirction I think it should go.  Compile-tested only for
> now.  Let me know what you think.

I thought about doing something similar but to make the logic the same it
becomes a bit awkward.

> 
> Ira, I used the same base as you.  If you updated ndctl, you'll have to
> revert 9e0391e057b36 to apply this patch.
> 
> Cheers,
> Jeff
> 
> diff --git a/ndctl/dimm.c b/ndctl/dimm.c
> index c8821d6..701f58b 100644
> --- a/ndctl/dimm.c
> +++ b/ndctl/dimm.c
> @@ -674,6 +674,41 @@ out:
>  	return rc;
>  }
>  
> +static void wait_for_cmd_completion(struct ndctl_cmd *cmd, struct fw_info *fw,
> +				    struct timespec *start)
> +{
> +	enum ND_FW_STATUS status;
> +	struct timespec sleeptime, now;
> +	int rc;
> +
> +	sleeptime.tv_nsec = fw->query_interval / 1000;
> +	sleeptime.tv_sec = 0;
> +
> +	while ((status = ndctl_cmd_fw_xlat_firmware_status(cmd)) == FW_EBUSY) {
> +
> +		rc = clock_gettime(CLOCK_MONOTONIC, &now);
> +		if (rc < 0)
> +			break;
> +
> +		/*
> +		 * If we expire max query time, we timed out
> +		 */
> +		if (now.tv_sec - start->tv_sec > fw->max_query / 1000000)
> +			break;
> +
> +		/*
> +		 * Sleep the interval dictated by firmware before
> +		 * query again.
> +		 */
> +		rc = nanosleep(&sleeptime, NULL);
> +		if (rc < 0)
> +			break;

You need ndctl_cmd_submit() here to be the same logic.

> +
> +	}
> +
> +	return;
> +}
> +
>  static int query_fw_finish_status(struct ndctl_dimm *dimm,
>  		struct action_context *actx)
>  {
> @@ -682,98 +717,65 @@ static int query_fw_finish_status(struct ndctl_dimm *dimm,
>  	struct ndctl_cmd *cmd;
>  	int rc;
>  	enum ND_FW_STATUS status;
> -	bool done = false;
> -	struct timespec now, before, after;
> +	struct timespec start;
>  	uint64_t ver;
>  
>  	cmd = ndctl_dimm_cmd_new_fw_finish_query(uctx->start);
>  	if (!cmd)
>  		return -ENXIO;
>  
> -	rc = clock_gettime(CLOCK_MONOTONIC, &before);
> +	rc = clock_gettime(CLOCK_MONOTONIC, &start);
>  	if (rc < 0)
> -		goto out;
> -
> -	now.tv_nsec = fw->query_interval / 1000;
> -	now.tv_sec = 0;
> -
> -	do {
> -		rc = ndctl_cmd_submit(cmd);
> -		if (rc < 0)
> -			break;
> +		goto unref;
>  
> -		status = ndctl_cmd_fw_xlat_firmware_status(cmd);
> -		switch (status) {
> -		case FW_SUCCESS:
> -			ver = ndctl_cmd_fw_fquery_get_fw_rev(cmd);
> -			if (ver == 0) {
> -				fprintf(stderr, "No firmware updated.\n");
> -				rc = -ENXIO;
> -				goto out;
> -			}
> -
> -			printf("Image updated successfully to DIMM %s.\n",
> -					ndctl_dimm_get_devname(dimm));
> -			printf("Firmware version %#lx.\n", ver);
> -			printf("Cold reboot to activate.\n");
> -			done = true;
> -			rc = 0;
> -			break;
> -		case FW_EBUSY:
> -			/* Still on going, continue */
> -			rc = clock_gettime(CLOCK_MONOTONIC, &after);
> -			if (rc < 0) {
> -				rc = -errno;
> -				goto out;
> -			}
> +	rc = ndctl_cmd_submit(cmd);
> +	if (rc < 0)
> +		goto unref;
>  
> -			/*
> -			 * If we expire max query time,
> -			 * we timed out
> -			 */
> -			if (after.tv_sec - before.tv_sec >
> -					fw->max_query / 1000000) {
> -				rc = -ETIMEDOUT;
> -				goto out;
> -			}
> +	wait_for_cmd_completion(cmd, fw, &start);

wait_for_cmd_completion() does not call ndctl_cmd_submit()

Now I find it odd that we need to resubmit the command but I assume the logic
is correct.  Therefore we need to go back and call ndctl_cmd_submit() again.

Or is this not required?

anyway that is why I went ahead and used the goto...

Ira
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