nvme: fix srcu locking on error return in nvme_get_ns_from_disk

If we can't get a namespace don't leak the SRCU lock.  nvme_ioctl was
working around this, but nvme_pr_command wasn't handling this properly.
Just do what callers would usually expect.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 308b9ce820cd..421bffd95aee 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1361,9 +1361,14 @@ static struct nvme_ns *nvme_get_ns_from_disk(struct gendisk *disk,
 {
 #ifdef CONFIG_NVME_MULTIPATH
         if (disk->fops == &nvme_ns_head_ops) {
+                struct nvme_ns *ns;
+
                 *head = disk->private_data;
                 *srcu_idx = srcu_read_lock(&(*head)->srcu);
-                return nvme_find_path(*head);
+                ns = nvme_find_path(*head);
+                if (!ns)
+                        srcu_read_unlock(&(*head)->srcu, *srcu_idx);
+                return ns;
         }
 #endif
         *head = NULL;
@@ -1410,9 +1415,9 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
 
         ns = nvme_get_ns_from_disk(bdev->bd_disk, &head, &srcu_idx);
         if (unlikely(!ns))
-                ret = -EWOULDBLOCK;
-        else
-                ret = nvme_ns_ioctl(ns, cmd, arg);
+                return -EWOULDBLOCK;
+
+        ret = nvme_ns_ioctl(ns, cmd, arg);
         nvme_put_ns_from_disk(head, srcu_idx);
         return ret;
 }