Re: [PATCH 02/10] scsi: restructure command initialization for TYPE_FS requests

[Hannes Reinecke <hare@suse.de>]

On 06/29/2014 03:34 PM, Christoph Hellwig wrote:
> We should call the device handler prep_fn for all TYPE_FS requests,
> not just simple read/write calls that are handled by the disk driver.
>
> Restructure the common I/O code to call the prep_fn handler and zero
> out the CDB, and just leave the call to scsi_init_io to the ULDs.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/scsi/scsi_lib.c    |   22 ++++++++++++----------
>   drivers/scsi/sd.c          |    2 +-
>   drivers/scsi/sr.c          |    3 +--
>   include/scsi/scsi_driver.h |    1 -
>   4 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index b505b06..bc84811 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1115,11 +1115,10 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
>   EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
>
>   /*
> - * Setup a REQ_TYPE_FS command.  These are simple read/write request
> - * from filesystems that still need to be translated to SCSI CDBs from
> - * the ULD.
> + * Setup a REQ_TYPE_FS command.  These are simple request from filesystems
> + * that still need to be translated to SCSI CDBs from the ULD.
>    */
> -int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
> +static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
>   {
>   	struct scsi_cmnd *cmd = req->special;
>
> @@ -1131,9 +1130,8 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
>   	}
>
>   	memset(cmd->cmnd, 0, BLK_MAX_CDB);
> -	return scsi_init_io(cmd, GFP_ATOMIC);
> +	return scsi_cmd_to_driver(cmd)->init_command(cmd);
>   }
> -EXPORT_SYMBOL(scsi_setup_fs_cmnd);
>
>   static int
>   scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
> @@ -1238,12 +1236,16 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
>   		goto out;
>   	}
>
> -	if (req->cmd_type == REQ_TYPE_FS)
> -		ret = scsi_cmd_to_driver(cmd)->init_command(cmd);
> -	else if (req->cmd_type == REQ_TYPE_BLOCK_PC)
> +	switch (req->cmd_type) {
> +	case REQ_TYPE_FS:
> +		ret = scsi_setup_fs_cmnd(sdev, req);
> +		break;
> +	case REQ_TYPE_BLOCK_PC:
>   		ret = scsi_setup_blk_pc_cmnd(sdev, req);
> -	else
> +		break;
> +	default:
>   		ret = BLKPREP_KILL;
> +	}
>
>   out:
>   	return scsi_prep_return(q, req, ret);
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 9c86e3d..001b3e8 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -894,7 +894,7 @@ static int sd_init_command(struct scsi_cmnd *SCpnt)
>   		ret = scsi_setup_flush_cmnd(sdp, rq);
>   		goto out;
>   	}
> -	ret = scsi_setup_fs_cmnd(sdp, rq);
> +	ret = scsi_init_io(SCpnt, GFP_ATOMIC);
>   	if (ret != BLKPREP_OK)
>   		goto out;
>   	SCpnt = rq->special;
> diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
> index a7ea27c..9feeb37 100644
> --- a/drivers/scsi/sr.c
> +++ b/drivers/scsi/sr.c
> @@ -385,10 +385,9 @@ static int sr_init_command(struct scsi_cmnd *SCpnt)
>   	int block = 0, this_count, s_size;
>   	struct scsi_cd *cd;
>   	struct request *rq = SCpnt->request;
> -	struct scsi_device *sdp = SCpnt->device;
>   	int ret;
>
> -	ret = scsi_setup_fs_cmnd(sdp, rq);
> +	ret = scsi_init_io(SCpnt, GFP_ATOMIC);
>   	if (ret != BLKPREP_OK)
>   		goto out;
>   	SCpnt = rq->special;
> diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
> index 36c4114..009d2ae 100644
> --- a/include/scsi/scsi_driver.h
> +++ b/include/scsi/scsi_driver.h
> @@ -30,6 +30,5 @@ extern int scsi_register_interface(struct class_interface *);
>   	class_interface_unregister(intf)
>
>   int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req);
> -int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req);
>
>   #endif /* _SCSI_SCSI_DRIVER_H */
>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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