ioctl: Rearrange members in nvme_ns_attach_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_ns_attach_args {
        int                        args_size;            /*     0     4 */
        int                        fd;                   /*     4     4 */
        __u32 *                    result;               /*     8     8 */
        __u32                      timeout;              /*    16     4 */
        __u32                      nsid;                 /*    20     4 */
        struct nvme_ctrl_list *    ctrlist;              /*    24     8 */
        enum nvme_ns_attach_sel    sel;                  /*    32     4 */

        /* size: 40, cachelines: 1, members: 7 */
        /* padding: 4 */
        /* last cacheline: 40 bytes */
} __attribute__((__aligned__(8)));

While at it also introduce the result member.

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

Author: dwsuse

src/nvme/ioctl.c

@@ -1203,7 +1203,7 @@ int nvme_ns_attach(struct nvme_ns_attach_args *args)
 
 	if (args->args_size < sizeof(*args))
 		return -EINVAL;
-	return nvme_submit_admin_passthru(args->fd, &cmd, NULL);
+	return nvme_submit_admin_passthru(args->fd, &cmd, args->result);
 }
 
 int nvme_fw_download(struct nvme_fw_download_args *args)

src/nvme/ioctl.h

@@ -2781,19 +2781,21 @@ static inline int nvme_ns_mgmt_delete(int fd, __u32 nsid)
 /**
  * nvme_ns_attach_args - Arguments for Nvme Namespace Management command
  * @fd:		File descriptor of nvme device
+ * @result:	NVMe command result
+ * @timeout:	Timeout in ms
  * @nsid:	Namespace ID to execute attach selection
- * @sel:	Attachment selection, see &enum nvme_ns_attach_sel
  * @ctrlist:	Controller list to modify attachment state of nsid
- * @timeout:	Timeout in ms
+ * @sel:	Attachment selection, see &enum nvme_ns_attach_sel
  */
 struct nvme_ns_attach_args {
 	int args_size;
 	int fd;
+	__u32 *result;
+	__u32 timeout;
 	__u32 nsid;
-	enum nvme_ns_attach_sel sel;
 	struct nvme_ctrl_list *ctrlist;
-	__u32 timeout;
-};
+	enum nvme_ns_attach_sel sel;
+} __attribute__((packed, aligned(__alignof__(__u32*))));
 
 /**
  * nvme_ns_attach_args - Attach or detach namespace to controller(s)
@@ -2813,10 +2815,11 @@ static inline int nvme_ns_attach_ctrls(int fd, __u32 nsid,
 	struct nvme_ns_attach_args args = {
 		.args_size = sizeof(args),
 		.fd = fd,
+		.result = NULL,
+		.timeout = NVME_DEFAULT_IOCTL_TIMEOUT,
 		.nsid = nsid,
-		.sel = NVME_NS_ATTACH_SEL_CTRL_ATTACH,
 		.ctrlist = ctrlist,
-		.timeout = NVME_DEFAULT_IOCTL_TIMEOUT,
+		.sel = NVME_NS_ATTACH_SEL_CTRL_ATTACH,
 	};
 
 	return nvme_ns_attach(&args);
@@ -2834,10 +2837,11 @@ static inline int nvme_ns_detach_ctrls(int fd, __u32 nsid,
 	struct nvme_ns_attach_args args = {
 		.args_size = sizeof(args),
 		.fd = fd,
+		.result = NULL,
+		.timeout = NVME_DEFAULT_IOCTL_TIMEOUT,
 		.nsid = nsid,
-		.sel = NVME_NS_ATTACH_SEL_CTRL_DEATTACH,
 		.ctrlist = ctrlist,
-		.timeout = NVME_DEFAULT_IOCTL_TIMEOUT,
+		.sel = NVME_NS_ATTACH_SEL_CTRL_DEATTACH,
 	};
 
 	return nvme_ns_attach(&args);