block: add bsg helper library

This moves the FC classes bsg code to the block layer and
makes it a lib so that other classes like iscsi and SAS can use it.

It is helpful because working with the request queue, bios,
creating scatterlists, etc are a pain that the LLD does not
have to worry about with normal IOs and should not have to
worry about for bsg requests.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/include/linux/bsg-lib.h b/include/linux/bsg-lib.h
new file mode 100644
index 0000000..f55ab8c
--- /dev/null
+++ b/include/linux/bsg-lib.h
@@ -0,0 +1,73 @@
+/*
+ *  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>
+
+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 request *req;
+
+	/* 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;
+
+	void *dd_data;		/* Used for driver-specific storage */
+};
+
+void bsg_job_done(struct bsg_job *job, int result,
+		  unsigned int reply_payload_rcv_len);
+int bsg_setup_queue(struct device *dev, struct request_queue *q, char *name,
+		    bsg_job_fn *job_fn, int dd_job_size);
+void bsg_request_fn(struct request_queue *q);
+void bsg_remove_queue(struct request_queue *q);
+void bsg_goose_queue(struct request_queue *q);
+
+#endif