pending-4.19/nvme-release-namespace-srcu-protection-before-perfor.patch

   1 From db251685664dd1cf36456732d5372b31b0f69d12 Mon Sep 17 00:00:00 2001
   2 From: Christoph Hellwig <hch@lst.de>
   3 Date: Fri, 17 May 2019 11:47:36 +0200
   4 Subject: nvme: release namespace SRCU protection before performing controller
   5  ioctls
   6
   7 [ Upstream commit 5fb4aac756acacf260b9ebd88747251effa3a2f2 ]
   8
   9 Holding the SRCU critical section protecting the namespace list can
  10 cause deadlocks when using the per-namespace admin passthrough ioctl to
  11 delete as namespace.  Release it earlier when performing per-controller
  12 ioctls to avoid that.
  13
  14 Reported-by: Kenneth Heitke <kenneth.heitke@intel.com>
  15 Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
  16 Reviewed-by: Keith Busch <keith.busch@intel.com>
  17 Signed-off-by: Christoph Hellwig <hch@lst.de>
  18 Signed-off-by: Sasha Levin <sashal@kernel.org>
  19 ---
  20  drivers/nvme/host/core.c | 25 ++++++++++++++++++++-----
  21  1 file changed, 20 insertions(+), 5 deletions(-)
  22
  23 diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
  24 index 82f5f1d030d4..818788275406 100644
  25 --- a/drivers/nvme/host/core.c
  26 +++ b/drivers/nvme/host/core.c
  27 @@ -1310,14 +1310,31 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
  28         if (unlikely(!ns))
  29                 return -EWOULDBLOCK;
  30
  31 +       /*
  32 +        * Handle ioctls that apply to the controller instead of the namespace
  33 +        * seperately and drop the ns SRCU reference early.  This avoids a
  34 +        * deadlock when deleting namespaces using the passthrough interface.
  35 +        */
  36 +       if (cmd == NVME_IOCTL_ADMIN_CMD || is_sed_ioctl(cmd)) {
  37 +               struct nvme_ctrl *ctrl = ns->ctrl;
  38 +
  39 +               nvme_get_ctrl(ns->ctrl);
  40 +               nvme_put_ns_from_disk(head, srcu_idx);
  41 +
  42 +               if (cmd == NVME_IOCTL_ADMIN_CMD)
  43 +                       ret = nvme_user_cmd(ctrl, NULL, argp);
  44 +               else
  45 +                       ret = sed_ioctl(ctrl->opal_dev, cmd, argp);
  46 +
  47 +               nvme_put_ctrl(ctrl);
  48 +               return ret;
  49 +       }
  50 +
  51         switch (cmd) {
  52         case NVME_IOCTL_ID:
  53                 force_successful_syscall_return();
  54                 ret = ns->head->ns_id;
  55                 break;
  56 -       case NVME_IOCTL_ADMIN_CMD:
  57 -               ret = nvme_user_cmd(ns->ctrl, NULL, argp);
  58 -               break;
  59         case NVME_IOCTL_IO_CMD:
  60                 ret = nvme_user_cmd(ns->ctrl, ns, argp);
  61                 break;
  62 @@ -1327,8 +1344,6 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
  63         default:
  64                 if (ns->ndev)
  65                         ret = nvme_nvm_ioctl(ns, cmd, arg);
  66 -               else if (is_sed_ioctl(cmd))
  67 -                       ret = sed_ioctl(ns->ctrl->opal_dev, cmd, argp);
  68                 else
  69                         ret = -ENOTTY;
  70         }
  71 --
  72 2.20.1
  73