queue-5.1/nvme-fix-srcu-locking-on-error-return-in-nvme_get_ns.patch

   1 From 5058ab089148342cfcee79ed39f01707e9747b32 Mon Sep 17 00:00:00 2001
   2 From: Christoph Hellwig <hch@lst.de>
   3 Date: Fri, 17 May 2019 02:47:33 -0700
   4 Subject: nvme: fix srcu locking on error return in nvme_get_ns_from_disk
   5
   6 [ Upstream commit 100c815cbd56480b3e31518475b04719c363614a ]
   7
   8 If we can't get a namespace don't leak the SRCU lock.  nvme_ioctl was
   9 working around this, but nvme_pr_command wasn't handling this properly.
  10 Just do what callers would usually expect.
  11
  12 Signed-off-by: Christoph Hellwig <hch@lst.de>
  13 Reviewed-by: Keith Busch <keith.busch@intel.com>
  14 Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
  15 Signed-off-by: Sasha Levin <sashal@kernel.org>
  16 ---
  17  drivers/nvme/host/core.c | 13 +++++++++----
  18  1 file changed, 9 insertions(+), 4 deletions(-)
  19
  20 diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
  21 index 8782d86a8ca3..e29c395f44d2 100644
  22 --- a/drivers/nvme/host/core.c
  23 +++ b/drivers/nvme/host/core.c
  24 @@ -1362,9 +1362,14 @@ static struct nvme_ns *nvme_get_ns_from_disk(struct gendisk *disk,
  25  {
  26  #ifdef CONFIG_NVME_MULTIPATH
  27         if (disk->fops == &nvme_ns_head_ops) {
  28 +               struct nvme_ns *ns;
  29 +
  30                 *head = disk->private_data;
  31                 *srcu_idx = srcu_read_lock(&(*head)->srcu);
  32 -               return nvme_find_path(*head);
  33 +               ns = nvme_find_path(*head);
  34 +               if (!ns)
  35 +                       srcu_read_unlock(&(*head)->srcu, *srcu_idx);
  36 +               return ns;
  37         }
  38  #endif
  39         *head = NULL;
  40 @@ -1411,9 +1416,9 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
  41
  42         ns = nvme_get_ns_from_disk(bdev->bd_disk, &head, &srcu_idx);
  43         if (unlikely(!ns))
  44 -               ret = -EWOULDBLOCK;
  45 -       else
  46 -               ret = nvme_ns_ioctl(ns, cmd, arg);
  47 +               return -EWOULDBLOCK;
  48 +
  49 +       ret = nvme_ns_ioctl(ns, cmd, arg);
  50         nvme_put_ns_from_disk(head, srcu_idx);
  51         return ret;
  52  }
  53 --
  54 2.20.1
  55