RE: [PATCH v2 10/11] megaraid_sas: Use Block layer API to check SCSI device in-flight IO requests

[Anand Lodnoor <anand.lodnoor@broadcom.com>]

Hannes,
               Thank you for pointing it out. Will incorporate the suggested
changes in the upcoming patches.

Thanks & Regards,
Anand R.L

-----Original Message-----
From: Hannes Reinecke [mailto:hare@suse.de]
Sent: Thursday, January 16, 2020 6:01 PM
To: Anand Lodnoor <anand.lodnoor@broadcom.com>; linux-scsi@vger.kernel.org
Cc: kashyap.desai@broadcom.com; sumit.saxena@broadcom.com;
kiran-kumar.kasturi@broadcom.com; sankar.patra@broadcom.com;
sasikumar.pc@broadcom.com; shivasharan.srikanteshwara@broadcom.com;
chandrakanth.patil@broadcom.com
Subject: Re: [PATCH v2 10/11] megaraid_sas: Use Block layer API to check
SCSI device in-flight IO requests

On 1/14/20 12:21 PM, Anand Lodnoor wrote:
> Remove usage of device_busy counter from driver. Instead of
> device_busy counter now driver uses 'nr_active' counter of
> request_queue to get the number of inflight request for a LUN.
>
> Link : https://patchwork.kernel.org/patch/11249297/
> Signed-off-by: Chandrakanth Patil <chandrakanth.patil@broadcom.com>
> Signed-off-by: Anand Lodnoor <anand.lodnoor@broadcom.com>
> ---
>  drivers/scsi/megaraid/megaraid_sas_fusion.c | 56
> ++++++++++++++++-------------
>  1 file changed, 31 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> index 0bdd477..f3b36fd 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> @@ -364,6 +364,35 @@ inline void megasas_return_cmd_fusion(struct
> megasas_instance *instance,
>  		instance->max_fw_cmds = instance->max_fw_cmds-1;
>  	}
>  }
> +
> +static inline void
> +megasas_get_msix_index(struct megasas_instance *instance,
> +		       struct scsi_cmnd *scmd,
> +		       struct megasas_cmd_fusion *cmd,
> +		       u8 data_arms)
> +{
> +	int sdev_busy;
> +
> +	/* nr_hw_queue = 1 for MegaRAID */
> +	struct blk_mq_hw_ctx *hctx =
> +		scmd->device->request_queue->queue_hw_ctx[0];
> +
While this might be true it would be better to use the hctx from the request
itself:

struct blk_mq_hw_ctx *hctx = scmd->request->mq_hctx;

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      Teamlead Storage & Networking
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB
36809 (AG Nürnberg), GF: Felix Imendörffer