[PATCH AUTOSEL 4.19 17/36] nvme: fix srcu locking on error return in nvme_get_ns_from_disk

[Sasha Levin]

From: Christoph Hellwig <h...@lst.de>

[ Upstream commit 100c815cbd56480b3e31518475b04719c363614a ]

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 <h...@lst.de>
Reviewed-by: Keith Busch <keith.bu...@intel.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulka...@wdc.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/nvme/host/core.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index abfb46378cc1..44d8077fbe95 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1277,9 +1277,14 @@ 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;
@@ -1326,9 +1331,9 @@ 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;
 }
-- 
2.20.1