[ Upstream commit 
a25d4261582cf00dad884c194d21084836663d3d ]
Commit 
89b3d6e60550 ("nvme: simplify the compat ioctl handling") removed
the initialization of compat_ioctl from the nvme block_device_operations
structures.
Presumably the expectation was that 32-bit ioctls would be directed
through the regular handler but this is not the case: failing to assign
.compat_ioctl actually means that the compat case is disabled entirely,
and any attempt to submit nvme ioctls from 32-bit userspace fails
outright with -ENOTTY.
For example:
  % smartctl -x /dev/nvme0n1
  [...]
  Read NVMe Identify Controller failed: NVME_IOCTL_ADMIN_CMD: Inappropriate ioctl for device
The blkdev_compat_ptr_ioctl helper can be used to direct compat calls
through the main ioctl handler and makes things work again.
Fixes: 89b3d6e60550 ("nvme: simplify the compat ioctl handling")
Signed-off-by: Nick Bowler <nbowler@draconx.ca>
Reviewed-by: Guixin Liu <kanie@linux.alibaba.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 static const struct block_device_operations nvme_bdev_ops = {
        .owner          = THIS_MODULE,
        .ioctl          = nvme_ioctl,
+       .compat_ioctl   = blkdev_compat_ptr_ioctl,
        .open           = nvme_open,
        .release        = nvme_release,
        .getgeo         = nvme_getgeo,
 
        .open           = nvme_ns_head_open,
        .release        = nvme_ns_head_release,
        .ioctl          = nvme_ns_head_ioctl,
+       .compat_ioctl   = blkdev_compat_ptr_ioctl,
        .getgeo         = nvme_getgeo,
        .report_zones   = nvme_ns_head_report_zones,
        .pr_ops         = &nvme_pr_ops,