[PATCH 5.19 0881/1157] nvme: define compat_ioctl again to unbreak 32-bit userspace.

Greg Kroah-Hartman
2022-08-16T04:46:38Z

From: Nick Bowler <nbowler@draconx.ca>

[ 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>
---
drivers/nvme/host/core.c | 1 +
drivers/nvme/host/multipath.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 6a12a906a11e..9c75d7378d31 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2123,6 +2123,7 @@ static int nvme_report_zones(struct gendisk *disk, sector_t sector,
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,
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index d3e2440d8abb..432ea9793a84 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -408,6 +408,7 @@ const struct block_device_operations nvme_ns_head_ops = {
.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,
--
2.35.1