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linux-next/include/linux/bsg-lib.h
Christoph Hellwig 17cb960f29 bsg: split handling of SCSI CDBs vs transport requeues
The current BSG design tries to shoe-horn the transport-specific
passthrough commands into the overall framework for SCSI passthrough
requests.  This has a couple problems:

 - each passthrough queue has to set the QUEUE_FLAG_SCSI_PASSTHROUGH flag
   despite not dealing with SCSI commands at all.  Because of that these
   queues could also incorrectly accept SCSI commands from in-kernel
   users or through the legacy SCSI_IOCTL_SEND_COMMAND ioctl.
 - the real SCSI bsg queues also incorrectly accept bsg requests of the
   BSG_SUB_PROTOCOL_SCSI_TRANSPORT type
 - the bsg transport code is almost unredable because it tries to reuse
   different SCSI concepts for its own purpose.

This patch instead adds a new bsg_ops structure to handle the two cases
differently, and thus solves all of the above problems.  Another side
effect is that the bsg-lib queues also don't need to embedd a
struct scsi_request anymore.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-13 11:40:24 -06:00

81 lines
2.2 KiB
C

/*
* BSG helper library
*
* Copyright (C) 2008 James Smart, Emulex Corporation
* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
* Copyright (C) 2011 Mike Christie
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#ifndef _BLK_BSG_
#define _BLK_BSG_
#include <linux/blkdev.h>
#include <scsi/scsi_request.h>
struct request;
struct device;
struct scatterlist;
struct request_queue;
struct bsg_buffer {
unsigned int payload_len;
int sg_cnt;
struct scatterlist *sg_list;
};
struct bsg_job {
struct device *dev;
struct kref kref;
unsigned int timeout;
/* Transport/driver specific request/reply structs */
void *request;
void *reply;
unsigned int request_len;
unsigned int reply_len;
/*
* On entry : reply_len indicates the buffer size allocated for
* the reply.
*
* Upon completion : the message handler must set reply_len
* to indicates the size of the reply to be returned to the
* caller.
*/
/* DMA payloads for the request/response */
struct bsg_buffer request_payload;
struct bsg_buffer reply_payload;
int result;
unsigned int reply_payload_rcv_len;
void *dd_data; /* Used for driver-specific storage */
};
void bsg_job_done(struct bsg_job *job, int result,
unsigned int reply_payload_rcv_len);
struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
bsg_job_fn *job_fn, int dd_job_size,
void (*release)(struct device *));
void bsg_job_put(struct bsg_job *job);
int __must_check bsg_job_get(struct bsg_job *job);
#endif