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authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>2008-04-19 00:43:14 +0900
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-04-22 15:16:32 -0500
commit97f46ae45c70857e459b7f8df1fc2807e7bd90a9 (patch)
tree7e7245349c433f67be23c6a75c3936c0466b59d6 /block/bsg.c
parent643eb2d932c97a0583381629d632d486934cf7ee (diff)
downloadlinux-linaro-stable-97f46ae45c70857e459b7f8df1fc2807e7bd90a9.tar.gz
[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>
Diffstat (limited to 'block/bsg.c')
-rw-r--r--block/bsg.c43
1 files changed, 29 insertions, 14 deletions
diff --git a/block/bsg.c b/block/bsg.c
index f51172ed27c2..23ea4fd1a66d 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -699,14 +699,26 @@ static struct bsg_device *bsg_alloc_device(void)
return bd;
}
+static void bsg_kref_release_function(struct kref *kref)
+{
+ struct bsg_class_device *bcd =
+ container_of(kref, struct bsg_class_device, ref);
+
+ if (bcd->release)
+ bcd->release(bcd->parent);
+
+ put_device(bcd->parent);
+}
+
static int bsg_put_device(struct bsg_device *bd)
{
- int ret = 0;
- struct device *dev = bd->queue->bsg_dev.dev;
+ int ret = 0, do_free;
+ struct request_queue *q = bd->queue;
mutex_lock(&bsg_mutex);
- if (!atomic_dec_and_test(&bd->ref_count))
+ do_free = atomic_dec_and_test(&bd->ref_count);
+ if (!do_free)
goto out;
dprintk("%s: tearing down\n", bd->name);
@@ -723,12 +735,13 @@ static int bsg_put_device(struct bsg_device *bd)
*/
ret = bsg_complete_all_commands(bd);
- blk_put_queue(bd->queue);
hlist_del(&bd->dev_list);
kfree(bd);
out:
mutex_unlock(&bsg_mutex);
- put_device(dev);
+ kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
+ if (do_free)
+ blk_put_queue(q);
return ret;
}
@@ -796,7 +809,7 @@ static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
mutex_lock(&bsg_mutex);
bcd = idr_find(&bsg_minor_idr, iminor(inode));
if (bcd)
- get_device(bcd->dev);
+ kref_get(&bcd->ref);
mutex_unlock(&bsg_mutex);
if (!bcd)
@@ -808,7 +821,7 @@ static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
bd = bsg_add_device(inode, bcd->queue, file);
if (IS_ERR(bd))
- put_device(bcd->dev);
+ kref_put(&bcd->ref, bsg_kref_release_function);
return bd;
}
@@ -947,14 +960,14 @@ void bsg_unregister_queue(struct request_queue *q)
idr_remove(&bsg_minor_idr, bcd->minor);
sysfs_remove_link(&q->kobj, "bsg");
device_unregister(bcd->class_dev);
- put_device(bcd->dev);
bcd->class_dev = NULL;
+ kref_put(&bcd->ref, bsg_kref_release_function);
mutex_unlock(&bsg_mutex);
}
EXPORT_SYMBOL_GPL(bsg_unregister_queue);
-int bsg_register_queue(struct request_queue *q, struct device *gdev,
- const char *name)
+int bsg_register_queue(struct request_queue *q, struct device *parent,
+ const char *name, void (*release)(struct device *))
{
struct bsg_class_device *bcd;
dev_t dev;
@@ -965,7 +978,7 @@ int bsg_register_queue(struct request_queue *q, struct device *gdev,
if (name)
devname = name;
else
- devname = gdev->bus_id;
+ devname = parent->bus_id;
/*
* we need a proper transport to send commands, not a stacked device
@@ -996,9 +1009,11 @@ int bsg_register_queue(struct request_queue *q, struct device *gdev,
bcd->minor = minor;
bcd->queue = q;
- bcd->dev = get_device(gdev);
+ bcd->parent = get_device(parent);
+ bcd->release = release;
+ kref_init(&bcd->ref);
dev = MKDEV(bsg_major, bcd->minor);
- class_dev = device_create(bsg_class, gdev, dev, "%s", devname);
+ class_dev = device_create(bsg_class, parent, dev, "%s", devname);
if (IS_ERR(class_dev)) {
ret = PTR_ERR(class_dev);
goto put_dev;
@@ -1017,7 +1032,7 @@ int bsg_register_queue(struct request_queue *q, struct device *gdev,
unregister_class_dev:
device_unregister(class_dev);
put_dev:
- put_device(gdev);
+ put_device(parent);
remove_idr:
idr_remove(&bsg_minor_idr, minor);
unlock: