ioctl: Rearrange members in nvme_copy_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_copy_args {
        int                        args_size;            /*     0     4 */
        int                        fd;                   /*     4     4 */
        __u32 *                    result;               /*     8     8 */
        __u32                      timeout;              /*    16     4 */
        __u32                      nsid;                 /*    20     4 */
        struct nvme_copy_range *   copy;                 /*    24     8 */
        __u64                      sdlba;                /*    32     8 */
        __u16                      nr;                   /*    40     2 */
        __u16                      dspec;                /*    42     2 */
        __u8                       prinfor;              /*    44     1 */
        __u8                       prinfow;              /*    45     1 */
        __u8                       dtype;                /*    46     1 */
        __u8                       format;               /*    47     1 */
        int                        lr;                   /*    48     4 */
        int                        fua;                  /*    52     4 */
        __u32                      ilbrt;                /*    56     4 */
        __u16                      lbatm;                /*    60     2 */
        __u16                      lbat;                 /*    62     2 */

        /* size: 64, cachelines: 1, members: 18 */
} __attribute__((__aligned__(8)));

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

Author: dwsuse

src/nvme/ioctl.h

@@ -3745,43 +3745,43 @@ int nvme_dsm(struct nvme_dsm_args *args);
 /**
  * nvme_copy_args - Arguments for the NVMe Copy command
  * @fd:		File descriptor of the nvme device
+ * @result:	The command completion result from CQE dword0
+ * @timeout:	Timeout in ms
  * @nsid:	Namespace identifier
  * @copy:	Range descriptior
  * @sdlba:	Start destination LBA
  * @nr:		Number of ranges
+ * @dspec:	Directive specific value
  * @prinfor:	Protection information field for read
  * @prinfow:	Protection information field for write
  * @dtype:	Directive type
- * @dspec:	Directive specific value
  * @format:	Descriptor format
  * @lr:		Limited retry
  * @fua:	Force unit access
  * @ilbrt:	Initial logical block reference tag
  * @lbatm:	Logical block application tag mask
  * @lbat:	Logical block application tag
- * @timeout:	Timeout in ms
- * @result:	The command completion result from CQE dword0
  */
 struct nvme_copy_args {
 	int args_size;
 	int fd;
+	__u32 *result;
+	__u32 timeout;
 	__u32 nsid;
 	struct nvme_copy_range *copy;
 	__u64 sdlba;
 	__u16 nr;
+	__u16 dspec;
 	__u8 prinfor;
 	__u8 prinfow;
 	__u8 dtype;
-	__u16 dspec;
 	__u8 format;
 	int lr;
 	int fua;
 	__u32 ilbrt;
 	__u16 lbatm;
 	__u16 lbat;
-	__u32 timeout;
-	__u32 *result;
-};
+} __attribute__((packed, aligned(__alignof__(__u64))));
 
 /**
  * nvme_copy() -