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>

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>
Mike Christie · Jens Axboe
1 parent 24c3047095
Showing 5 changed files with 385 additions and 0 deletions Side-by-side Diff
block/Kconfig
block/Makefile
block/bsg-lib.c
include/linux/blkdev.h
include/linux/bsg-lib.h
@@ -65,6 +65,16 @@
  
 	  If unsure, say Y.
  
+config BLK_DEV_BSGLIB
+	bool "Block layer SG support v4 helper lib"
+	default n
+	select BLK_DEV_BSG
+	help
+	  Subsystems will normally enable this if needed. Users will not
+	  normally need to manually enable this.
+
+	  If unsure, say N.
+
 config BLK_DEV_INTEGRITY
 	bool "Block layer data integrity support"
 	---help---
@@ -8,6 +8,7 @@
 			blk-iopoll.o blk-lib.o ioctl.o genhd.o scsi_ioctl.o
  
 obj-$(CONFIG_BLK_DEV_BSG)	+= bsg.o
+obj-$(CONFIG_BLK_DEV_BSGLIB)	+= bsg-lib.o
 obj-$(CONFIG_BLK_CGROUP)	+= blk-cgroup.o
 obj-$(CONFIG_BLK_DEV_THROTTLING)	+= blk-throttle.o
 obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
+/*
+ *  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
+ *
+ */
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/scatterlist.h>
+#include <linux/bsg-lib.h>
+#include <scsi/scsi_cmnd.h>
+
+/**
+ * bsg_destroy_job - routine to teardown/delete a bsg job
+ * @job: bsg_job that is to be torn down
+ */
+static void bsg_destroy_job(struct bsg_job *job)
+{
+	put_device(job->dev);	/* release reference for the request */
+
+	kfree(job->request_payload.sg_list);
+	kfree(job->reply_payload.sg_list);
+	kfree(job);
+}
+
+/**
+ * bsg_job_done - completion routine for bsg requests
+ * @job: bsg_job that is complete
+ * @result: job reply result
+ * @reply_payload_rcv_len: length of payload recvd
+ *
+ * The LLD should call this when the bsg job has completed.
+ */
+void bsg_job_done(struct bsg_job *job, int result,
+		  unsigned int reply_payload_rcv_len)
+{
+	struct request *req = job->req;
+	struct request *rsp = req->next_rq;
+	int err;
+
+	err = job->req->errors = result;
+	if (err < 0)
+		/* we're only returning the result field in the reply */
+		job->req->sense_len = sizeof(u32);
+	else
+		job->req->sense_len = job->reply_len;
+	/* we assume all request payload was transferred, residual == 0 */
+	req->resid_len = 0;
+
+	if (rsp) {
+		WARN_ON(reply_payload_rcv_len > rsp->resid_len);
+
+		/* set reply (bidi) residual */
+		rsp->resid_len -= min(reply_payload_rcv_len, rsp->resid_len);
+	}
+	blk_complete_request(req);
+}
+EXPORT_SYMBOL_GPL(bsg_job_done);
+
+/**
+ * bsg_softirq_done - softirq done routine for destroying the bsg requests
+ * @rq: BSG request that holds the job to be destroyed
+ */
+static void bsg_softirq_done(struct request *rq)
+{
+	struct bsg_job *job = rq->special;
+
+	blk_end_request_all(rq, rq->errors);
+	bsg_destroy_job(job);
+}
+
+static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
+{
+	size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
+
+	BUG_ON(!req->nr_phys_segments);
+
+	buf->sg_list = kzalloc(sz, GFP_KERNEL);
+	if (!buf->sg_list)
+		return -ENOMEM;
+	sg_init_table(buf->sg_list, req->nr_phys_segments);
+	buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
+	buf->payload_len = blk_rq_bytes(req);
+	return 0;
+}
+
+/**
+ * bsg_create_job - create the bsg_job structure for the bsg request
+ * @dev: device that is being sent the bsg request
+ * @req: BSG request that needs a job structure
+ */
+static int bsg_create_job(struct device *dev, struct request *req)
+{
+	struct request *rsp = req->next_rq;
+	struct request_queue *q = req->q;
+	struct bsg_job *job;
+	int ret;
+
+	BUG_ON(req->special);
+
+	job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL);
+	if (!job)
+		return -ENOMEM;
+
+	req->special = job;
+	job->req = req;
+	if (q->bsg_job_size)
+		job->dd_data = (void *)&job[1];
+	job->request = req->cmd;
+	job->request_len = req->cmd_len;
+	job->reply = req->sense;
+	job->reply_len = SCSI_SENSE_BUFFERSIZE;	/* Size of sense buffer
+						 * allocated */
+	if (req->bio) {
+		ret = bsg_map_buffer(&job->request_payload, req);
+		if (ret)
+			goto failjob_rls_job;
+	}
+	if (rsp && rsp->bio) {
+		ret = bsg_map_buffer(&job->reply_payload, rsp);
+		if (ret)
+			goto failjob_rls_rqst_payload;
+	}
+	job->dev = dev;
+	/* take a reference for the request */
+	get_device(job->dev);
+	return 0;
+
+failjob_rls_rqst_payload:
+	kfree(job->request_payload.sg_list);
+failjob_rls_job:
+	kfree(job);
+	return -ENOMEM;
+}
+
+/*
+ * bsg_goose_queue - restart queue in case it was stopped
+ * @q: request q to be restarted
+ */
+void bsg_goose_queue(struct request_queue *q)
+{
+	if (!q)
+		return;
+
+	blk_run_queue_async(q);
+}
+EXPORT_SYMBOL_GPL(bsg_goose_queue);
+
+/**
+ * bsg_request_fn - generic handler for bsg requests
+ * @q: request queue to manage
+ *
+ * On error the create_bsg_job function should return a -Exyz error value
+ * that will be set to the req->errors.
+ *
+ * Drivers/subsys should pass this to the queue init function.
+ */
+void bsg_request_fn(struct request_queue *q)
+{
+	struct device *dev = q->queuedata;
+	struct request *req;
+	struct bsg_job *job;
+	int ret;
+
+	if (!get_device(dev))
+		return;
+
+	while (1) {
+		req = blk_fetch_request(q);
+		if (!req)
+			break;
+		spin_unlock_irq(q->queue_lock);
+
+		ret = bsg_create_job(dev, req);
+		if (ret) {
+			req->errors = ret;
+			blk_end_request_all(req, ret);
+			spin_lock_irq(q->queue_lock);
+			continue;
+		}
+
+		job = req->special;
+		ret = q->bsg_job_fn(job);
+		spin_lock_irq(q->queue_lock);
+		if (ret)
+			break;
+	}
+
+	spin_unlock_irq(q->queue_lock);
+	put_device(dev);
+	spin_lock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL_GPL(bsg_request_fn);
+
+/**
+ * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
+ * @dev: device to attach bsg device to
+ * @q: request queue setup by caller
+ * @name: device to give bsg device
+ * @job_fn: bsg job handler
+ * @dd_job_size: size of LLD data needed for each job
+ *
+ * The caller should have setup the reuqest queue with bsg_request_fn
+ * as the request_fn.
+ */
+int bsg_setup_queue(struct device *dev, struct request_queue *q,
+		    char *name, bsg_job_fn *job_fn, int dd_job_size)
+{
+	int ret;
+
+	q->queuedata = dev;
+	q->bsg_job_size = dd_job_size;
+	q->bsg_job_fn = job_fn;
+	queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
+	blk_queue_softirq_done(q, bsg_softirq_done);
+	blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
+
+	ret = bsg_register_queue(q, dev, name, NULL);
+	if (ret) {
+		printk(KERN_ERR "%s: bsg interface failed to "
+		       "initialize - register queue\n", dev->kobj.name);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(bsg_setup_queue);
+
+/**
+ * bsg_remove_queue - Deletes the bsg dev from the q
+ * @q:	the request_queue that is to be torn down.
+ *
+ * Notes:
+ *   Before unregistering the queue empty any requests that are blocked
+ */
+void bsg_remove_queue(struct request_queue *q)
+{
+	struct request *req; /* block request */
+	int counts; /* totals for request_list count and starved */
+
+	if (!q)
+		return;
+
+	/* Stop taking in new requests */
+	spin_lock_irq(q->queue_lock);
+	blk_stop_queue(q);
+
+	/* drain all requests in the queue */
+	while (1) {
+		/* need the lock to fetch a request
+		 * this may fetch the same reqeust as the previous pass
+		 */
+		req = blk_fetch_request(q);
+		/* save requests in use and starved */
+		counts = q->rq.count[0] + q->rq.count[1] +
+			 q->rq.starved[0] + q->rq.starved[1];
+		spin_unlock_irq(q->queue_lock);
+		/* any requests still outstanding? */
+		if (counts == 0)
+			break;
+
+		/* This may be the same req as the previous iteration,
+		 * always send the blk_end_request_all after a prefetch.
+		 * It is not okay to not end the request because the
+		 * prefetch started the request.
+		 */
+		if (req) {
+			/* return -ENXIO to indicate that this queue is
+			 * going away
+			 */
+			req->errors = -ENXIO;
+			blk_end_request_all(req, -ENXIO);
+		}
+
+		msleep(200); /* allow bsg to possibly finish */
+		spin_lock_irq(q->queue_lock);
+	}
+	bsg_unregister_queue(q);
+}
+EXPORT_SYMBOL_GPL(bsg_remove_queue);
@@ -30,6 +30,7 @@
 struct blk_trace;
 struct request;
 struct sg_io_hdr;
+struct bsg_job;
  
 #define BLKDEV_MIN_RQ	4
 #define BLKDEV_MAX_RQ	128	/* Default maximum */
@@ -209,6 +210,7 @@
 typedef void (softirq_done_fn)(struct request *);
 typedef int (dma_drain_needed_fn)(struct request *);
 typedef int (lld_busy_fn) (struct request_queue *q);
+typedef int (bsg_job_fn) (struct bsg_job *);
  
 enum blk_eh_timer_return {
 	BLK_EH_NOT_HANDLED,
@@ -375,6 +377,8 @@
 	struct mutex		sysfs_lock;
  
 #if defined(CONFIG_BLK_DEV_BSG)
+	bsg_job_fn		*bsg_job_fn;
+	int			bsg_job_size;
 	struct bsg_class_device bsg_dev;
 #endif
  
+/*
+ *  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
...	...	@@ -65,6 +65,16 @@
65	65
66	66	If unsure, say Y.
67	67
	68	+config BLK_DEV_BSGLIB
	69	+ bool "Block layer SG support v4 helper lib"
	70	+ default n
	71	+ select BLK_DEV_BSG
	72	+ help
	73	+ Subsystems will normally enable this if needed. Users will not
	74	+ normally need to manually enable this.
	75	+
	76	+ If unsure, say N.
	77	+
68	78	config BLK_DEV_INTEGRITY
69	79	bool "Block layer data integrity support"
70	80	---help---
...	...	@@ -8,6 +8,7 @@
8	8	blk-iopoll.o blk-lib.o ioctl.o genhd.o scsi_ioctl.o
9	9
10	10	obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
	11	+obj-$(CONFIG_BLK_DEV_BSGLIB) += bsg-lib.o
11	12	obj-$(CONFIG_BLK_CGROUP) += blk-cgroup.o
12	13	obj-$(CONFIG_BLK_DEV_THROTTLING) += blk-throttle.o
13	14	obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
	1	+/*
	2	+ * BSG helper library
	3	+ *
	4	+ * Copyright (C) 2008 James Smart, Emulex Corporation
	5	+ * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
	6	+ * Copyright (C) 2011 Mike Christie
	7	+ *
	8	+ * This program is free software; you can redistribute it and/or modify
	9	+ * it under the terms of the GNU General Public License as published by
	10	+ * the Free Software Foundation; either version 2 of the License, or
	11	+ * (at your option) any later version.
	12	+ *
	13	+ * This program is distributed in the hope that it will be useful,
	14	+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	+ * GNU General Public License for more details.
	17	+ *
	18	+ * You should have received a copy of the GNU General Public License
	19	+ * along with this program; if not, write to the Free Software
	20	+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	21	+ *
	22	+ */
	23	+#include <linux/slab.h>
	24	+#include <linux/blkdev.h>
	25	+#include <linux/delay.h>
	26	+#include <linux/scatterlist.h>
	27	+#include <linux/bsg-lib.h>
	28	+#include <scsi/scsi_cmnd.h>
	29	+
	30	+/**
	31	+ * bsg_destroy_job - routine to teardown/delete a bsg job
	32	+ * @job: bsg_job that is to be torn down
	33	+ */
	34	+static void bsg_destroy_job(struct bsg_job *job)
	35	+{
	36	+ put_device(job->dev); /* release reference for the request */
	37	+
	38	+ kfree(job->request_payload.sg_list);
	39	+ kfree(job->reply_payload.sg_list);
	40	+ kfree(job);
	41	+}
	42	+
	43	+/**
	44	+ * bsg_job_done - completion routine for bsg requests
	45	+ * @job: bsg_job that is complete
	46	+ * @result: job reply result
	47	+ * @reply_payload_rcv_len: length of payload recvd
	48	+ *
	49	+ * The LLD should call this when the bsg job has completed.
	50	+ */
	51	+void bsg_job_done(struct bsg_job *job, int result,
	52	+ unsigned int reply_payload_rcv_len)
	53	+{
	54	+ struct request *req = job->req;
	55	+ struct request *rsp = req->next_rq;
	56	+ int err;
	57	+
	58	+ err = job->req->errors = result;
	59	+ if (err < 0)
	60	+ /* we're only returning the result field in the reply */
	61	+ job->req->sense_len = sizeof(u32);
	62	+ else
	63	+ job->req->sense_len = job->reply_len;
	64	+ /* we assume all request payload was transferred, residual == 0 */
	65	+ req->resid_len = 0;
	66	+
	67	+ if (rsp) {
	68	+ WARN_ON(reply_payload_rcv_len > rsp->resid_len);
	69	+
	70	+ /* set reply (bidi) residual */
	71	+ rsp->resid_len -= min(reply_payload_rcv_len, rsp->resid_len);
	72	+ }
	73	+ blk_complete_request(req);
	74	+}
	75	+EXPORT_SYMBOL_GPL(bsg_job_done);
	76	+
	77	+/**
	78	+ * bsg_softirq_done - softirq done routine for destroying the bsg requests
	79	+ * @rq: BSG request that holds the job to be destroyed
	80	+ */
	81	+static void bsg_softirq_done(struct request *rq)
	82	+{
	83	+ struct bsg_job *job = rq->special;
	84	+
	85	+ blk_end_request_all(rq, rq->errors);
	86	+ bsg_destroy_job(job);
	87	+}
	88	+
	89	+static int bsg_map_buffer(struct bsg_buffer buf, struct request req)
	90	+{
	91	+ size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments);
	92	+
	93	+ BUG_ON(!req->nr_phys_segments);
	94	+
	95	+ buf->sg_list = kzalloc(sz, GFP_KERNEL);
	96	+ if (!buf->sg_list)
	97	+ return -ENOMEM;
	98	+ sg_init_table(buf->sg_list, req->nr_phys_segments);
	99	+ buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list);
	100	+ buf->payload_len = blk_rq_bytes(req);
	101	+ return 0;
	102	+}
	103	+
	104	+/**
	105	+ * bsg_create_job - create the bsg_job structure for the bsg request
	106	+ * @dev: device that is being sent the bsg request
	107	+ * @req: BSG request that needs a job structure
	108	+ */
	109	+static int bsg_create_job(struct device dev, struct request req)
	110	+{
	111	+ struct request *rsp = req->next_rq;
	112	+ struct request_queue *q = req->q;
	113	+ struct bsg_job *job;
	114	+ int ret;
	115	+
	116	+ BUG_ON(req->special);
	117	+
	118	+ job = kzalloc(sizeof(struct bsg_job) + q->bsg_job_size, GFP_KERNEL);
	119	+ if (!job)
	120	+ return -ENOMEM;
	121	+
	122	+ req->special = job;
	123	+ job->req = req;
	124	+ if (q->bsg_job_size)
	125	+ job->dd_data = (void *)&job[1];
	126	+ job->request = req->cmd;
	127	+ job->request_len = req->cmd_len;
	128	+ job->reply = req->sense;
	129	+ job->reply_len = SCSI_SENSE_BUFFERSIZE; /* Size of sense buffer
	130	+ * allocated */
	131	+ if (req->bio) {
	132	+ ret = bsg_map_buffer(&job->request_payload, req);
	133	+ if (ret)
	134	+ goto failjob_rls_job;
	135	+ }
	136	+ if (rsp && rsp->bio) {
	137	+ ret = bsg_map_buffer(&job->reply_payload, rsp);
	138	+ if (ret)
	139	+ goto failjob_rls_rqst_payload;
	140	+ }
	141	+ job->dev = dev;
	142	+ /* take a reference for the request */
	143	+ get_device(job->dev);
	144	+ return 0;
	145	+
	146	+failjob_rls_rqst_payload:
	147	+ kfree(job->request_payload.sg_list);
	148	+failjob_rls_job:
	149	+ kfree(job);
	150	+ return -ENOMEM;
	151	+}
	152	+
	153	+/*
	154	+ * bsg_goose_queue - restart queue in case it was stopped
	155	+ * @q: request q to be restarted
	156	+ */
	157	+void bsg_goose_queue(struct request_queue *q)
	158	+{
	159	+ if (!q)
	160	+ return;
	161	+
	162	+ blk_run_queue_async(q);
	163	+}
	164	+EXPORT_SYMBOL_GPL(bsg_goose_queue);
	165	+
	166	+/**
	167	+ * bsg_request_fn - generic handler for bsg requests
	168	+ * @q: request queue to manage
	169	+ *
	170	+ * On error the create_bsg_job function should return a -Exyz error value
	171	+ * that will be set to the req->errors.
	172	+ *
	173	+ * Drivers/subsys should pass this to the queue init function.
	174	+ */
	175	+void bsg_request_fn(struct request_queue *q)
	176	+{
	177	+ struct device *dev = q->queuedata;
	178	+ struct request *req;
	179	+ struct bsg_job *job;
	180	+ int ret;
	181	+
	182	+ if (!get_device(dev))
	183	+ return;
	184	+
	185	+ while (1) {
	186	+ req = blk_fetch_request(q);
	187	+ if (!req)
	188	+ break;
	189	+ spin_unlock_irq(q->queue_lock);
	190	+
	191	+ ret = bsg_create_job(dev, req);
	192	+ if (ret) {
	193	+ req->errors = ret;
	194	+ blk_end_request_all(req, ret);
	195	+ spin_lock_irq(q->queue_lock);
	196	+ continue;
	197	+ }
	198	+
	199	+ job = req->special;
	200	+ ret = q->bsg_job_fn(job);
	201	+ spin_lock_irq(q->queue_lock);
	202	+ if (ret)
	203	+ break;
	204	+ }
	205	+
	206	+ spin_unlock_irq(q->queue_lock);
	207	+ put_device(dev);
	208	+ spin_lock_irq(q->queue_lock);
	209	+}
	210	+EXPORT_SYMBOL_GPL(bsg_request_fn);
	211	+
	212	+/**
	213	+ * bsg_setup_queue - Create and add the bsg hooks so we can receive requests
	214	+ * @dev: device to attach bsg device to
	215	+ * @q: request queue setup by caller
	216	+ * @name: device to give bsg device
	217	+ * @job_fn: bsg job handler
	218	+ * @dd_job_size: size of LLD data needed for each job
	219	+ *
	220	+ * The caller should have setup the reuqest queue with bsg_request_fn
	221	+ * as the request_fn.
	222	+ */
	223	+int bsg_setup_queue(struct device dev, struct request_queue q,
	224	+ char name, bsg_job_fn job_fn, int dd_job_size)
	225	+{
	226	+ int ret;
	227	+
	228	+ q->queuedata = dev;
	229	+ q->bsg_job_size = dd_job_size;
	230	+ q->bsg_job_fn = job_fn;
	231	+ queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
	232	+ blk_queue_softirq_done(q, bsg_softirq_done);
	233	+ blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
	234	+
	235	+ ret = bsg_register_queue(q, dev, name, NULL);
	236	+ if (ret) {
	237	+ printk(KERN_ERR "%s: bsg interface failed to "
	238	+ "initialize - register queue\n", dev->kobj.name);
	239	+ return ret;
	240	+ }
	241	+
	242	+ return 0;
	243	+}
	244	+EXPORT_SYMBOL_GPL(bsg_setup_queue);
	245	+
	246	+/**
	247	+ * bsg_remove_queue - Deletes the bsg dev from the q
	248	+ * @q: the request_queue that is to be torn down.
	249	+ *
	250	+ * Notes:
	251	+ * Before unregistering the queue empty any requests that are blocked
	252	+ */
	253	+void bsg_remove_queue(struct request_queue *q)
	254	+{
	255	+ struct request req; / block request */
	256	+ int counts; /* totals for request_list count and starved */
	257	+
	258	+ if (!q)
	259	+ return;
	260	+
	261	+ /* Stop taking in new requests */
	262	+ spin_lock_irq(q->queue_lock);
	263	+ blk_stop_queue(q);
	264	+
	265	+ /* drain all requests in the queue */
	266	+ while (1) {
	267	+ /* need the lock to fetch a request
	268	+ * this may fetch the same reqeust as the previous pass
	269	+ */
	270	+ req = blk_fetch_request(q);
	271	+ /* save requests in use and starved */
	272	+ counts = q->rq.count[0] + q->rq.count[1] +
	273	+ q->rq.starved[0] + q->rq.starved[1];
	274	+ spin_unlock_irq(q->queue_lock);
	275	+ /* any requests still outstanding? */
	276	+ if (counts == 0)
	277	+ break;
	278	+
	279	+ /* This may be the same req as the previous iteration,
	280	+ * always send the blk_end_request_all after a prefetch.
	281	+ * It is not okay to not end the request because the
	282	+ * prefetch started the request.
	283	+ */
	284	+ if (req) {
	285	+ /* return -ENXIO to indicate that this queue is
	286	+ * going away
	287	+ */
	288	+ req->errors = -ENXIO;
	289	+ blk_end_request_all(req, -ENXIO);
	290	+ }
	291	+
	292	+ msleep(200); /* allow bsg to possibly finish */
	293	+ spin_lock_irq(q->queue_lock);
	294	+ }
	295	+ bsg_unregister_queue(q);
	296	+}
	297	+EXPORT_SYMBOL_GPL(bsg_remove_queue);
...	...	@@ -30,6 +30,7 @@
30	30	struct blk_trace;
31	31	struct request;
32	32	struct sg_io_hdr;
	33	+struct bsg_job;
33	34
34	35	#define BLKDEV_MIN_RQ 4
35	36	#define BLKDEV_MAX_RQ 128 /* Default maximum */
...	...	@@ -209,6 +210,7 @@
209	210	typedef void (softirq_done_fn)(struct request *);
210	211	typedef int (dma_drain_needed_fn)(struct request *);
211	212	typedef int (lld_busy_fn) (struct request_queue *q);
	213	+typedef int (bsg_job_fn) (struct bsg_job *);
212	214
213	215	enum blk_eh_timer_return {
214	216	BLK_EH_NOT_HANDLED,
...	...	@@ -375,6 +377,8 @@
375	377	struct mutex sysfs_lock;
376	378
377	379	#if defined(CONFIG_BLK_DEV_BSG)
	380	+ bsg_job_fn *bsg_job_fn;
	381	+ int bsg_job_size;
378	382	struct bsg_class_device bsg_dev;
379	383	#endif
380	384