scsi: bsg: Simplify device registration

Use the per-device cdev_device_interface to store the bsg data in the char
device inode, and thus remove the need to embedd the bsg_class_device
structure in the request_queue.

Link: https://lore.kernel.org/r/20210729064845.1044147-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

3 files changed, 21 insertions, 19 deletions

diff --git a/drivers/scsi/scsi_bsg.c b/drivers/scsi/scsi_bsg.c
index 68f60316adf1..c0d41c45c2be 100644
--- a/drivers/scsi/scsi_bsg.c
+++ b/drivers/scsi/scsi_bsg.c
@@ -89,7 +89,8 @@ static const struct bsg_ops scsi_bsg_ops = {
 	.free_rq		= scsi_bsg_free_rq,
 };
 
-int scsi_bsg_register_queue(struct request_queue *q, struct device *parent)
+struct bsg_device *scsi_bsg_register_queue(struct scsi_device *sdev)
 {
-	return bsg_register_queue(q, parent, dev_name(parent), &scsi_bsg_ops);
+	return bsg_register_queue(sdev->request_queue, &sdev->sdev_gendev,
+				  dev_name(&sdev->sdev_gendev), &scsi_bsg_ops);
 }
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 0a0db35bab04..6d9152031a40 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -7,6 +7,7 @@
 #include <scsi/scsi_device.h>
 #include <linux/sbitmap.h>
 
+struct bsg_device;
 struct request_queue;
 struct request;
 struct scsi_cmnd;
@@ -180,15 +181,7 @@ static inline void scsi_dh_add_device(struct scsi_device *sdev) { }
 static inline void scsi_dh_release_device(struct scsi_device *sdev) { }
 #endif
 
-#ifdef CONFIG_BLK_DEV_BSG
-int scsi_bsg_register_queue(struct request_queue *q, struct device *parent);
-#else
-static inline int scsi_bsg_register_queue(struct request_queue *q,
-		struct device *parent)
-{
-	return 0;
-}
-#endif
+struct bsg_device *scsi_bsg_register_queue(struct scsi_device *sdev);
 
 extern int scsi_device_max_queue_depth(struct scsi_device *sdev);
 
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 4ff9ac3296d8..07cee8dc4100 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -13,6 +13,7 @@
 #include <linux/blkdev.h>
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
+#include <linux/bsg.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
@@ -1327,7 +1328,6 @@ static int scsi_target_add(struct scsi_target *starget)
 int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 {
 	int error, i;
-	struct request_queue *rq = sdev->request_queue;
 	struct scsi_target *starget = sdev->sdev_target;
 
 	error = scsi_target_add(starget);
@@ -1366,12 +1366,19 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 	transport_add_device(&sdev->sdev_gendev);
 	sdev->is_visible = 1;
 
-	error = scsi_bsg_register_queue(rq, &sdev->sdev_gendev);
-	if (error)
-		/* we're treating error on bsg register as non-fatal,
-		 * so pretend nothing went wrong */
-		sdev_printk(KERN_INFO, sdev,
-			    "Failed to register bsg queue, errno=%d\n", error);
+	if (IS_ENABLED(CONFIG_BLK_DEV_BSG)) {
+		sdev->bsg_dev = scsi_bsg_register_queue(sdev);
+		if (IS_ERR(sdev->bsg_dev)) {
+			/*
+			 * We're treating error on bsg register as non-fatal, so
+			 * pretend nothing went wrong.
+			 */
+			sdev_printk(KERN_INFO, sdev,
+				    "Failed to register bsg queue, errno=%d\n",
+				    error);
+			sdev->bsg_dev = NULL;
+		}
+	}
 
 	/* add additional host specific attributes */
 	if (sdev->host->hostt->sdev_attrs) {
@@ -1433,7 +1440,8 @@ void __scsi_remove_device(struct scsi_device *sdev)
 			sysfs_remove_groups(&sdev->sdev_gendev.kobj,
 					sdev->host->hostt->sdev_groups);
 
-		bsg_unregister_queue(sdev->request_queue);
+		if (IS_ENABLED(CONFIG_BLK_DEV_BSG) && sdev->bsg_dev)
+			bsg_unregister_queue(sdev->bsg_dev);
 		device_unregister(&sdev->sdev_dev);
 		transport_remove_device(dev);
 		device_del(dev);