[SCSI] bsg: add release callback support

This patch adds release callback support, which is called when a bsg
device goes away. bsg_register_queue() takes a pointer to a callback
function. This feature is useful for stuff like sas_host that can't
use the release callback in struct device.

If a caller doesn't need bsg's release callback, it can call
bsg_register_queue() with NULL pointer (e.g. scsi devices can use
release callback in struct device so they don't need bsg's callback).

With this patch, bsg uses kref for refcounts on bsg devices instead of
get/put_device in fops->open/release. bsg calls put_device and the
caller's release callback (if it was registered) in kref_put's
release.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 198aa4571e35..049103f1d16f 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -889,7 +889,7 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
                 goto out;
         }
 
-        error = bsg_register_queue(rq, &sdev->sdev_gendev, NULL);
+        error = bsg_register_queue(rq, &sdev->sdev_gendev, NULL, NULL);
 
         if (error)
                 sdev_printk(KERN_INFO, sdev,
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 27ec625ab771..94ff29f7c34b 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -219,7 +219,7 @@ static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy)
         if (!q)
                 return -ENOMEM;
 
-        error = bsg_register_queue(q, dev, name);
+        error = bsg_register_queue(q, dev, name, NULL);
         if (error) {
                 blk_cleanup_queue(q);
                 return -ENOMEM;