nvme: Fix nvme_get/set_features() with a NULL result pointer

nvme_set_features() callers seem to expect that passing NULL as the
result pointer is acceptable.  Teach nvme_set_features() not to try to
write to the NULL address.

For symmetry, make the same change to nvme_get_features(), despite the
fact that all current callers pass a valid result pointer.

I assume that this bug hasn't been reported in practice because
the callers that pass NULL are all in the SCSI translation layer
and no one uses the relevant operations.

Cc: stable@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7f75d661237f..2feacc70bf61 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -611,7 +611,7 @@ int nvme_get_features(struct nvme_ctrl *dev, unsigned fid, unsigned nsid,
 
         ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &cqe, NULL, 0, 0,
                         NVME_QID_ANY, 0, 0);
-        if (ret >= 0)
+        if (ret >= 0 && result)
                 *result = le32_to_cpu(cqe.result);
         return ret;
 }
@@ -631,7 +631,7 @@ int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword11,
 
         ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &cqe, NULL, 0, 0,
                         NVME_QID_ANY, 0, 0);
-        if (ret >= 0)
+        if (ret >= 0 && result)
                 *result = le32_to_cpu(cqe.result);
         return ret;
 }