diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 47d3cdd6ddf1..94d82cb96626 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1039,9 +1039,6 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
 	printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors,
 			req->current_nr_sectors);
 
-	/* release the command and kill it */
-	scsi_release_buffers(cmd);
-	scsi_put_command(cmd);
 	return BLKPREP_KILL;
 }
 
@@ -1078,9 +1075,13 @@ static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
 	scsi_io_completion(cmd, cmd->request_bufflen);
 }
 
-static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
+int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 {
 	struct scsi_cmnd *cmd;
+	int ret = scsi_prep_state_check(sdev, req);
+
+	if (ret != BLKPREP_OK)
+		return ret;
 
 	cmd = scsi_get_cmd_from_req(sdev, req);
 	if (unlikely(!cmd))
@@ -1126,18 +1127,20 @@ static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 	cmd->done = scsi_blk_pc_done;
 	return BLKPREP_OK;
 }
+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.
  */
-static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
+int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
 {
 	struct scsi_cmnd *cmd;
-	struct scsi_driver *drv;
-	int ret;
+	int ret = scsi_prep_state_check(sdev, req);
 
+	if (ret != BLKPREP_OK)
+		return ret;
 	/*
 	 * Filesystem requests must transfer data.
 	 */
@@ -1147,26 +1150,12 @@ static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
 	if (unlikely(!cmd))
 		return BLKPREP_DEFER;
 
-	ret = scsi_init_io(cmd);
-	if (unlikely(ret))
-		return ret;
-
-	/*
-	 * Initialize the actual SCSI command for this request.
-	 */
-	drv = *(struct scsi_driver **)req->rq_disk->private_data;
-	if (unlikely(!drv->init_command(cmd))) {
-		scsi_release_buffers(cmd);
-		scsi_put_command(cmd);
-		return BLKPREP_KILL;
-	}
-
-	return BLKPREP_OK;
+	return scsi_init_io(cmd);
 }
+EXPORT_SYMBOL(scsi_setup_fs_cmnd);
 
-static int scsi_prep_fn(struct request_queue *q, struct request *req)
+int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
 {
-	struct scsi_device *sdev = q->queuedata;
 	int ret = BLKPREP_OK;
 
 	/*
@@ -1212,35 +1201,25 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 				ret = BLKPREP_KILL;
 			break;
 		}
-
-		if (ret != BLKPREP_OK)
-			goto out;
 	}
+	return ret;
+}
+EXPORT_SYMBOL(scsi_prep_state_check);
 
-	switch (req->cmd_type) {
-	case REQ_TYPE_BLOCK_PC:
-		ret = scsi_setup_blk_pc_cmnd(sdev, req);
-		break;
-	case REQ_TYPE_FS:
-		ret = scsi_setup_fs_cmnd(sdev, req);
-		break;
-	default:
-		/*
-		 * All other command types are not supported.
-		 *
-		 * Note that these days the SCSI subsystem does not use
-		 * REQ_TYPE_SPECIAL requests anymore.  These are only used
-		 * (directly or via blk_insert_request) by non-SCSI drivers.
-		 */
-		blk_dump_rq_flags(req, "SCSI bad req");
-		ret = BLKPREP_KILL;
-		break;
-	}
+int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
+{
+	struct scsi_device *sdev = q->queuedata;
 
- out:
 	switch (ret) {
 	case BLKPREP_KILL:
 		req->errors = DID_NO_CONNECT << 16;
+		/* release the command and kill it */
+		if (req->special) {
+			struct scsi_cmnd *cmd = req->special;
+			scsi_release_buffers(cmd);
+			scsi_put_command(cmd);
+			req->special = NULL;
+		}
 		break;
 	case BLKPREP_DEFER:
 		/*
@@ -1257,6 +1236,17 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req)
 
 	return ret;
 }
+EXPORT_SYMBOL(scsi_prep_return);
+
+static int scsi_prep_fn(struct request_queue *q, struct request *req)
+{
+	struct scsi_device *sdev = q->queuedata;
+	int ret = BLKPREP_KILL;
+
+	if (req->cmd_type == REQ_TYPE_BLOCK_PC)
+		ret = scsi_setup_blk_pc_cmnd(sdev, req);
+	return scsi_prep_return(q, req, ret);
+}
 
 /*
  * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 2c6116fd4578..38a41415004b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -240,7 +240,6 @@ static struct scsi_driver sd_template = {
 		.shutdown	= sd_shutdown,
 	},
 	.rescan			= sd_rescan,
-	.init_command		= sd_init_command,
 };
 
 /*
@@ -331,14 +330,31 @@ static void scsi_disk_put(struct scsi_disk *sdkp)
  *
  *	Returns 1 if successful and 0 if error (or cannot be done now).
  **/
-static int sd_init_command(struct scsi_cmnd * SCpnt)
+static int sd_prep_fn(struct request_queue *q, struct request *rq)
 {
-	struct scsi_device *sdp = SCpnt->device;
-	struct request *rq = SCpnt->request;
+	struct scsi_cmnd *SCpnt;
+	struct scsi_device *sdp = q->queuedata;
 	struct gendisk *disk = rq->rq_disk;
 	sector_t block = rq->sector;
-	unsigned int this_count = SCpnt->request_bufflen >> 9;
+	unsigned int this_count = rq->nr_sectors;
 	unsigned int timeout = sdp->timeout;
+	int ret;
+
+	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
+		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
+		goto out;
+	} else if (rq->cmd_type != REQ_TYPE_FS) {
+		ret = BLKPREP_KILL;
+		goto out;
+	}
+	ret = scsi_setup_fs_cmnd(sdp, rq);
+	if (ret != BLKPREP_OK)
+		goto out;
+	SCpnt = rq->special;
+
+	/* from here on until we're complete, any goto out
+	 * is used for a killable error condition */
+	ret = BLKPREP_KILL;
 
 	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
 					"sd_init_command: block=%llu, "
@@ -353,7 +369,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 						rq->nr_sectors));
 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
 						"Retry with 0x%p\n", SCpnt));
-		return 0;
+		goto out;
 	}
 
 	if (sdp->changed) {
@@ -362,8 +378,9 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 		 * the changed bit has been reset
 		 */
 		/* printk("SCSI disk has been changed. Prohibiting further I/O.\n"); */
-		return 0;
+		goto out;
 	}
+
 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt, "block=%llu\n",
 					(unsigned long long)block));
 
@@ -382,7 +399,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 		if ((block & 1) || (rq->nr_sectors & 1)) {
 			scmd_printk(KERN_ERR, SCpnt,
 				    "Bad block number requested\n");
-			return 0;
+			goto out;
 		} else {
 			block = block >> 1;
 			this_count = this_count >> 1;
@@ -392,7 +409,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 		if ((block & 3) || (rq->nr_sectors & 3)) {
 			scmd_printk(KERN_ERR, SCpnt,
 				    "Bad block number requested\n");
-			return 0;
+			goto out;
 		} else {
 			block = block >> 2;
 			this_count = this_count >> 2;
@@ -402,7 +419,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 		if ((block & 7) || (rq->nr_sectors & 7)) {
 			scmd_printk(KERN_ERR, SCpnt,
 				    "Bad block number requested\n");
-			return 0;
+			goto out;
 		} else {
 			block = block >> 3;
 			this_count = this_count >> 3;
@@ -410,7 +427,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 	}
 	if (rq_data_dir(rq) == WRITE) {
 		if (!sdp->writeable) {
-			return 0;
+			goto out;
 		}
 		SCpnt->cmnd[0] = WRITE_6;
 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
@@ -419,7 +436,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
 	} else {
 		scmd_printk(KERN_ERR, SCpnt, "Unknown command %x\n", rq->cmd_flags);
-		return 0;
+		goto out;
 	}
 
 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
@@ -470,7 +487,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 			 */
 			scmd_printk(KERN_ERR, SCpnt,
 				    "FUA write on READ/WRITE(6) drive\n");
-			return 0;
+			goto out;
 		}
 
 		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
@@ -501,7 +518,9 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 	 * This indicates that the command is ready from our end to be
 	 * queued.
 	 */
-	return 1;
+	ret = BLKPREP_OK;
+ out:
+	return scsi_prep_return(q, rq, ret);
 }
 
 /**
@@ -1669,6 +1688,7 @@ static int sd_probe(struct device *dev)
 
 	sd_revalidate_disk(gd);
 
+	blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
 	blk_queue_issue_flush_fn(sdp->request_queue, sd_issue_flush);
 
 	gd->driverfs_dev = &sdp->sdev_gendev;
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 902eb11ffe8a..a0c4e13d4dab 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -78,7 +78,6 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
 
 static int sr_probe(struct device *);
 static int sr_remove(struct device *);
-static int sr_init_command(struct scsi_cmnd *);
 
 static struct scsi_driver sr_template = {
 	.owner			= THIS_MODULE,
@@ -87,7 +86,6 @@ static struct scsi_driver sr_template = {
 		.probe		= sr_probe,
 		.remove		= sr_remove,
 	},
-	.init_command		= sr_init_command,
 };
 
 static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
@@ -296,19 +294,39 @@ static void rw_intr(struct scsi_cmnd * SCpnt)
 	scsi_io_completion(SCpnt, good_bytes);
 }
 
-static int sr_init_command(struct scsi_cmnd * SCpnt)
+static int sr_prep_fn(struct request_queue *q, struct request *rq)
 {
 	int block=0, this_count, s_size, timeout = SR_TIMEOUT;
-	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
+	struct scsi_cd *cd;
+	struct scsi_cmnd *SCpnt;
+	struct scsi_device *sdp = q->queuedata;
+	int ret;
+
+	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
+		ret = scsi_setup_blk_pc_cmnd(sdp, rq);
+		goto out;
+	} else if (rq->cmd_type != REQ_TYPE_FS) {
+		ret = BLKPREP_KILL;
+		goto out;
+	}
+	ret = scsi_setup_fs_cmnd(sdp, rq);
+	if (ret != BLKPREP_OK)
+		goto out;
+	SCpnt = rq->special;
+	cd = scsi_cd(rq->rq_disk);
+
+	/* from here on until we're complete, any goto out
+	 * is used for a killable error condition */
+	ret = BLKPREP_KILL;
 
 	SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
 				cd->disk->disk_name, block));
 
 	if (!cd->device || !scsi_device_online(cd->device)) {
 		SCSI_LOG_HLQUEUE(2, printk("Finishing %ld sectors\n",
-					SCpnt->request->nr_sectors));
+					rq->nr_sectors));
 		SCSI_LOG_HLQUEUE(2, printk("Retry with 0x%p\n", SCpnt));
-		return 0;
+		goto out;
 	}
 
 	if (cd->device->changed) {
@@ -316,7 +334,7 @@ static int sr_init_command(struct scsi_cmnd * SCpnt)
 		 * quietly refuse to do anything to a changed disc until the
 		 * changed bit has been reset
 		 */
-		return 0;
+		goto out;
 	}
 
 	/*
@@ -333,21 +351,21 @@ static int sr_init_command(struct scsi_cmnd * SCpnt)
 
 	if (s_size != 512 && s_size != 1024 && s_size != 2048) {
 		scmd_printk(KERN_ERR, SCpnt, "bad sector size %d\n", s_size);
-		return 0;
+		goto out;
 	}
 
-	if (rq_data_dir(SCpnt->request) == WRITE) {
+	if (rq_data_dir(rq) == WRITE) {
 		if (!cd->device->writeable)
-			return 0;
+			goto out;
 		SCpnt->cmnd[0] = WRITE_10;
 		SCpnt->sc_data_direction = DMA_TO_DEVICE;
  	 	cd->cdi.media_written = 1;
-	} else if (rq_data_dir(SCpnt->request) == READ) {
+	} else if (rq_data_dir(rq) == READ) {
 		SCpnt->cmnd[0] = READ_10;
 		SCpnt->sc_data_direction = DMA_FROM_DEVICE;
 	} else {
-		blk_dump_rq_flags(SCpnt->request, "Unknown sr command");
-		return 0;
+		blk_dump_rq_flags(rq, "Unknown sr command");
+		goto out;
 	}
 
 	{
@@ -368,10 +386,10 @@ static int sr_init_command(struct scsi_cmnd * SCpnt)
 	/*
 	 * request doesn't start on hw block boundary, add scatter pads
 	 */
-	if (((unsigned int)SCpnt->request->sector % (s_size >> 9)) ||
+	if (((unsigned int)rq->sector % (s_size >> 9)) ||
 	    (SCpnt->request_bufflen % s_size)) {
 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
-		return 0;
+		goto out;
 	}
 
 	this_count = (SCpnt->request_bufflen >> 9) / (s_size >> 9);
@@ -379,12 +397,12 @@ static int sr_init_command(struct scsi_cmnd * SCpnt)
 
 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
 				cd->cdi.name,
-				(rq_data_dir(SCpnt->request) == WRITE) ?
+				(rq_data_dir(rq) == WRITE) ?
 					"writing" : "reading",
-				this_count, SCpnt->request->nr_sectors));
+				this_count, rq->nr_sectors));
 
 	SCpnt->cmnd[1] = 0;
-	block = (unsigned int)SCpnt->request->sector / (s_size >> 9);
+	block = (unsigned int)rq->sector / (s_size >> 9);
 
 	if (this_count > 0xffff) {
 		this_count = 0xffff;
@@ -419,7 +437,9 @@ static int sr_init_command(struct scsi_cmnd * SCpnt)
 	 * This indicates that the command is ready from our end to be
 	 * queued.
 	 */
-	return 1;
+	ret = BLKPREP_OK;
+ out:
+	return scsi_prep_return(q, rq, ret);
 }
 
 static int sr_block_open(struct inode *inode, struct file *file)
@@ -590,6 +610,7 @@ static int sr_probe(struct device *dev)
 
 	/* FIXME: need to handle a get_capabilities failure properly ?? */
 	get_capabilities(cd);
+	blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
 	sr_vendor_init(cd);
 
 	disk->driverfs_dev = &sdev->sdev_gendev;
diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
index 3465f31a21c4..56a304709fde 100644
--- a/include/scsi/scsi_driver.h
+++ b/include/scsi/scsi_driver.h
@@ -5,13 +5,15 @@
 
 struct module;
 struct scsi_cmnd;
+struct scsi_device;
+struct request;
+struct request_queue;
 
 
 struct scsi_driver {
 	struct module		*owner;
 	struct device_driver	gendrv;
 
-	int (*init_command)(struct scsi_cmnd *);
 	void (*rescan)(struct device *);
 };
 #define to_scsi_driver(drv) \
@@ -25,4 +27,9 @@ extern int scsi_register_interface(struct class_interface *);
 #define scsi_unregister_interface(intf) \
 	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);
+int scsi_prep_state_check(struct scsi_device *sdev, struct request *req);
+int scsi_prep_return(struct request_queue *q, struct request *req, int ret);
+
 #endif /* _SCSI_SCSI_DRIVER_H */
diff --git a/include/scsi/sd.h b/include/scsi/sd.h
index ce02ad1f5185..aa1e71613010 100644
--- a/include/scsi/sd.h
+++ b/include/scsi/sd.h
@@ -55,7 +55,6 @@ static void sd_shutdown(struct device *dev);
 static int sd_suspend(struct device *dev, pm_message_t state);
 static int sd_resume(struct device *dev);
 static void sd_rescan(struct device *);
-static int  sd_init_command(struct scsi_cmnd *);
 static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
 static void scsi_disk_release(struct class_device *cdev);
 static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);