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authorChristoph Hellwig <hch@lst.de>2018-05-29 08:40:23 +0200
committerJens Axboe <axboe@kernel.dk>2018-05-29 13:00:25 -0600
commit5de815a7eedfacf593817ef34634eaa9b75a1482 (patch)
tree13cca552662936096f7b306dc5dbb7b64dfdd93e /block/bsg.c
parentb7405176b58aa475354f3c0d2ca1c560e9354288 (diff)
downloadlinux-stericsson-5de815a7eedfacf593817ef34634eaa9b75a1482.tar.gz
block: remove parent device reference from struct bsg_class_device
Bsg holding a reference to the parent device may result in a crash if a bsg file handle is closed after the parent device driver has unloaded. Holding a reference is not really needed: the parent device must exist between bsg_register_queue and bsg_unregister_queue. Before the device goes away the caller does blk_cleanup_queue so that all in-flight requests to the device are gone and all new requests cannot pass beyond the queue. The queue itself is a refcounted object and it will stay alive with a bsg file. Based on analysis, previous patch and changelog from Anatoliy Glagolev. Reported-by: Anatoliy Glagolev <glagolig@gmail.com> Reviewed-by: James E.J. Bottomley <jejb@linux.vnet.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bsg.c')
-rw-r--r--block/bsg.c39
1 files changed, 5 insertions, 34 deletions
diff --git a/block/bsg.c b/block/bsg.c
index 30876c5fbf15..132e657e2d91 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -649,18 +649,6 @@ 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);
- struct device *parent = bcd->parent;
-
- if (bcd->release)
- bcd->release(bcd->parent);
-
- put_device(parent);
-}
-
static int bsg_put_device(struct bsg_device *bd)
{
int ret = 0, do_free;
@@ -693,7 +681,6 @@ static int bsg_put_device(struct bsg_device *bd)
kfree(bd);
out:
- kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
if (do_free)
blk_put_queue(q);
return ret;
@@ -759,8 +746,6 @@ 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)
- kref_get(&bcd->ref);
mutex_unlock(&bsg_mutex);
if (!bcd)
@@ -771,8 +756,6 @@ static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
return bd;
bd = bsg_add_device(inode, bcd->queue, file);
- if (IS_ERR(bd))
- kref_put(&bcd->ref, bsg_kref_release_function);
return bd;
}
@@ -912,25 +895,17 @@ void bsg_unregister_queue(struct request_queue *q)
sysfs_remove_link(&q->kobj, "bsg");
device_unregister(bcd->class_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 *parent,
- const char *name, const struct bsg_ops *ops,
- void (*release)(struct device *))
+ const char *name, const struct bsg_ops *ops)
{
struct bsg_class_device *bcd;
dev_t dev;
int ret;
struct device *class_dev = NULL;
- const char *devname;
-
- if (name)
- devname = name;
- else
- devname = dev_name(parent);
/*
* we need a proper transport to send commands, not a stacked device
@@ -954,15 +929,12 @@ int bsg_register_queue(struct request_queue *q, struct device *parent,
bcd->minor = ret;
bcd->queue = q;
- bcd->parent = get_device(parent);
- bcd->release = release;
bcd->ops = ops;
- kref_init(&bcd->ref);
dev = MKDEV(bsg_major, bcd->minor);
- class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
+ class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name);
if (IS_ERR(class_dev)) {
ret = PTR_ERR(class_dev);
- goto put_dev;
+ goto idr_remove;
}
bcd->class_dev = class_dev;
@@ -977,8 +949,7 @@ int bsg_register_queue(struct request_queue *q, struct device *parent,
unregister_class_dev:
device_unregister(class_dev);
-put_dev:
- put_device(parent);
+idr_remove:
idr_remove(&bsg_minor_idr, bcd->minor);
unlock:
mutex_unlock(&bsg_mutex);
@@ -992,7 +963,7 @@ int bsg_scsi_register_queue(struct request_queue *q, struct device *parent)
return -EINVAL;
}
- return bsg_register_queue(q, parent, NULL, &bsg_scsi_ops, NULL);
+ return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops);
}
EXPORT_SYMBOL_GPL(bsg_scsi_register_queue);