NVMe: Reference count open namespaces
Dynamic namespace attachment means the namespace may be removed at any
time, so the namespace reference count can not be tied to the device
reference count. This fixes a NULL dereference if an opened namespace
is detached from a controller.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 6f04771..b02ae3d 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1943,6 +1943,18 @@
#define nvme_compat_ioctl NULL
#endif
+static void nvme_free_ns(struct kref *kref)
+{
+ struct nvme_ns *ns = container_of(kref, struct nvme_ns, kref);
+
+ spin_lock(&dev_list_lock);
+ ns->disk->private_data = NULL;
+ spin_unlock(&dev_list_lock);
+
+ put_disk(ns->disk);
+ kfree(ns);
+}
+
static int nvme_open(struct block_device *bdev, fmode_t mode)
{
int ret = 0;
@@ -1952,21 +1964,25 @@
ns = bdev->bd_disk->private_data;
if (!ns)
ret = -ENXIO;
- else if (!kref_get_unless_zero(&ns->dev->kref))
+ else if (!kref_get_unless_zero(&ns->kref))
ret = -ENXIO;
+ else if (!kref_get_unless_zero(&ns->dev->kref)) {
+ kref_put(&ns->kref, nvme_free_ns);
+ ret = -ENXIO;
+ }
spin_unlock(&dev_list_lock);
return ret;
}
static void nvme_free_dev(struct kref *kref);
-
static void nvme_release(struct gendisk *disk, fmode_t mode)
{
struct nvme_ns *ns = disk->private_data;
struct nvme_dev *dev = ns->dev;
kref_put(&dev->kref, nvme_free_dev);
+ kref_put(&ns->kref, nvme_free_ns);
}
static int nvme_getgeo(struct block_device *bd, struct hd_geometry *geo)
@@ -2126,6 +2142,7 @@
if (!disk)
goto out_free_queue;
+ kref_init(&ns->kref);
ns->ns_id = nsid;
ns->disk = disk;
ns->lba_shift = 9; /* set to a default value for 512 until disk is validated */
@@ -2360,13 +2377,7 @@
static void nvme_free_namespace(struct nvme_ns *ns)
{
list_del(&ns->list);
-
- spin_lock(&dev_list_lock);
- ns->disk->private_data = NULL;
- spin_unlock(&dev_list_lock);
-
- put_disk(ns->disk);
- kfree(ns);
+ kref_put(&ns->kref, nvme_free_ns);
}
static int ns_cmp(void *priv, struct list_head *a, struct list_head *b)