RE: [PATCH 10/14] scsi: only maintain target_blocked if the driver has a target queue limit

[Elliott, Robert (Server Storage)]

> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@xxxxxx]
> Sent: Thursday, 12 June, 2014 8:49 AM
> To: James Bottomley
> Cc: Jens Axboe; Bart Van Assche; Elliott, Robert (Server Storage); linux-
> scsi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: [PATCH 10/14] scsi: only maintain target_blocked if the driver has a
> target queue limit
> 
> This saves us an atomic operation for each I/O submission and completion
> for the usual case where the driver doesn't set a per-target can_queue
> value.  Only a few iscsi hardware offload drivers set the per-target
> can_queue value at the moment.
> 
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  drivers/scsi/scsi_lib.c |   17 ++++++++++++-----
>  1 file changed, 12 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 0e33dee..763b3c9 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
...

> @@ -1642,7 +1648,8 @@ static void scsi_request_fn(struct request_queue *q)
>  	return;
> 
>   host_not_ready:
> -	atomic_dec(&scsi_target(sdev)->target_busy);
> +	if (&scsi_target(sdev)->can_queue > 0)
> +		atomic_dec(&scsi_target(sdev)->target_busy);
>   not_ready:
>  	/*
>  	 * lock q, handle tag, requeue req, and decrement device_busy. We

There's an extra & in that if statement.

---
Rob Elliott    HP Server Storage



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/