From 5de815a7eedfacf593817ef34634eaa9b75a1482 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 29 May 2018 08:40:23 +0200 Subject: 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 Reviewed-by: James E.J. Bottomley Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/bsg.c | 39 +++++---------------------------------- 1 file changed, 5 insertions(+), 34 deletions(-) (limited to 'block/bsg.c') 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); -- cgit v1.2.3