ioctl: Rearrange members in nvme_virtual_mgmt_args

Avoid any holes in the struct by rearranging the members. Also add the
attribute packed to struct definition to reduce ABI breakage.

struct nvme_virtual_mgmt_args {
        int                        args_size;            /*     0     4 */
        int                        fd;                   /*     4     4 */
        __u32 *                    result;               /*     8     8 */
        __u32                      timeout;              /*    16     4 */
        enum nvme_virt_mgmt_act    act;                  /*    20     4 */
        enum nvme_virt_mgmt_rt     rt;                   /*    24     4 */
        __u16                      cntlid;               /*    28     2 */
        __u16                      nr;                   /*    30     2 */

        /* size: 32, cachelines: 1, members: 8 */
        /* last cacheline: 32 bytes */
} __attribute__((__aligned__(8)));

Signed-off-by: Daniel Wagner <[email protected]>

Author: dwsuse

src/nvme/ioctl.h

@@ -3507,23 +3507,23 @@ int nvme_dev_self_test(struct nvme_dev_self_test_args *args);
  * nvme_virtual_mgmt_args - Arguments for the NVMe Virtualization
  * 			    resource management command
  * @fd:		File descriptor of nvme device
+ * @result:	If successful, the CQE dword0
+ * @timeout:	Timeout in ms
  * @act:	Virtual resource action, see &enum nvme_virt_mgmt_act
  * @rt:		Resource type to modify, see &enum nvme_virt_mgmt_rt
  * @cntlid:	Controller id for which resources are bing modified
  * @nr:		Number of resources being allocated or assigned
- * @timeout:	Timeout in ms
- * @result:	If successful, the CQE dword0
  */
 struct nvme_virtual_mgmt_args {
 	int args_size;
 	int fd;
+	__u32 *result;
+	__u32 timeout;
 	enum nvme_virt_mgmt_act act;
 	enum nvme_virt_mgmt_rt rt;
 	__u16 cntlid;
 	__u16 nr;
-	__u32 timeout;
-	__u32 *result;
-};
+} __attribute__((packed, aligned(__alignof__(__u32*))));
 
 /**
  * nvme_virtual_mgmt() - Virtualization resource management