ioctl: Rearrange members in nvme_zns_mgmt_send_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_zns_mgmt_send_args {
        int                        args_size;            /*     0     4 */
        int                        fd;                   /*     4     4 */
        __u32 *                    result;               /*     8     8 */
        __u32                      timeout;              /*    16     4 */
        __u32                      nsid;                 /*    20     4 */
        __u64                      slba;                 /*    24     8 */
        enum nvme_zns_send_action  zsa;                  /*    32     4 */
        __u32                      data_len;             /*    36     4 */
        void *                     data;                 /*    40     8 */
        _Bool                      select_all;           /*    48     1 */
        __u8                       zsaso;                /*    49     1 */

        /* size: 56, cachelines: 1, members: 11 */
        /* padding: 6 */
        /* last cacheline: 56 bytes */
} __attribute__((__aligned__(8)));

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

Author: dwsuse

src/nvme/ioctl.h

@@ -3939,29 +3939,29 @@ int nvme_resv_report(struct nvme_resv_report_args *args);
 /**
  * nvme_zns_mgmt_send_args - Arguments for the NVMe ZNS Management Send command
  * @fd:		File descriptor of nvme device
+ * @result:	The command completion result from CQE dword0
+ * @timeout:	timeout in ms
  * @nsid:	Namespace ID
  * @slba:	Starting logical block address
  * @zsa:	Zone send action
- * @select_all:	Select all flag
- * @zsaso:	Zone Send Action Specific Option
  * @data_len:	Length of @data
  * @data:	Userspace address of the data
- * @timeout:	timeout in ms
- * @result:	The command completion result from CQE dword0
+ * @select_all:	Select all flag
+ * @zsaso:	Zone Send Action Specific Option
  */
 struct nvme_zns_mgmt_send_args {
 	int args_size;
 	int fd;
+	__u32 *result;
+	__u32 timeout;
 	__u32 nsid;
 	__u64 slba;
 	enum nvme_zns_send_action zsa;
-	bool select_all;
-	__u8 zsaso;
 	__u32 data_len;
 	void *data;
-	__u32 timeout;
-	__u32 *result;
-};
+	bool select_all;
+	__u8 zsaso;
+} __attribute__((packed, aligned(__alignof__(__u64))));
 
 /**
  * nvme_zns_mgmt_send() -