[PATCH 3/3] nvme: add parameter command_retry to enable retry

[Minwoo Im]

Hello,

On 21-01-12 09:09:26, Christoph Hellwig wrote:
> On Fri, Jan 08, 2021 at 11:46:59PM +0900, Minwoo Im wrote:
> > This patch added a module parameter named command_retry to turn on the
> > command retry feature in this driver.  If turning it on,
> > REQ3_FAILFAST_DRIVER will not be set to requests so that retry can be
> > reached out to nvme_retry_req() based on the module parameter.
> 
> Why would we want to do that, and if so why only conditional on a module
> parameter?

If reqeust->cmd_flags are set with the REQ_FAILFAST_DRIVER in
nvme_init_request(), then it will always go to COMPLETE case rather than
RETRY in nvme_decide_disposition():

	if (blk_noretry_request(req) ||
		...

And I thought that to make command delay feature enabled, module
parameter was a good start to toggle this feature.

Thanks!