[PATCH] nvme: change nvme_passthru_cmd64's result field.

[Charles Machalow]

Changing nvme_passthru_cmd64's result field to be backwards compatible
with the nvme_passthru_cmd/nvme_admin_cmd struct in terms of the result
field. With this change the first 32 bits of result in either case
point to CQE DW0. This allows userspace tools to use the new structure
when using the old ADMIN/IO_CMD ioctls or new ADMIN/IO_CMD64 ioctls.

Signed-off-by: Charles Machalow <csm10495@xxxxxxxxx>
---
 drivers/nvme/host/core.c        | 4 ++--
 include/uapi/linux/nvme_ioctl.h | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index fa7ba09dc..74a7cc2dd 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1453,11 +1453,11 @@ static int nvme_user_cmd64(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
 	status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
 			(void __user *)(uintptr_t)cmd.addr, cmd.data_len,
 			(void __user *)(uintptr_t)cmd.metadata, cmd.metadata_len,
-			0, &cmd.result, timeout);
+			0, (u64 *)&cmd.result, timeout);
 	nvme_passthru_end(ctrl, effects);
 
 	if (status >= 0) {
-		if (put_user(cmd.result, &ucmd->result))
+		if (put_user(*(u64 *)&cmd.result, (u64 *)&ucmd->result))
 			return -EFAULT;
 	}
 
diff --git a/include/uapi/linux/nvme_ioctl.h b/include/uapi/linux/nvme_ioctl.h
index e168dc59e..4cb07bd6d 100644
--- a/include/uapi/linux/nvme_ioctl.h
+++ b/include/uapi/linux/nvme_ioctl.h
@@ -63,7 +63,7 @@ struct nvme_passthru_cmd64 {
 	__u32	cdw14;
 	__u32	cdw15;
 	__u32	timeout_ms;
-	__u64	result;
+	__u32	result[2];
 };
 
 #define nvme_admin_cmd nvme_passthru_cmd
-- 
2.17.1