Move zfs_cmd_t copyin/copyout to platform code

FreeBSD needs to cope with multiple version of the zfs_cmd_t
structure. Allowing the platform code to pre and post
process the cmd structure makes it possible to work with
legacy tooling.

Reviewed-by: Jorgen Lundman <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Matt Macy <[email protected]>
Closes #9624 

2 files changed, 24 insertions, 21 deletions

diff --git a/module/os/linux/zfs/zfs_ioctl_os.c b/module/os/linux/zfs/zfs_ioctl_os.c
index fa47c30ea..2960832a5 100644
--- a/module/os/linux/zfs/zfs_ioctl_os.c
+++ b/module/os/linux/zfs/zfs_ioctl_os.c
@@ -168,9 +168,25 @@ static long
 zfsdev_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
 {
 	uint_t vecnum;
+	zfs_cmd_t *zc;
+	int error, rc;
 
 	vecnum = cmd - ZFS_IOC_FIRST;
-	return (zfsdev_ioctl_common(vecnum, arg));
+
+	zc = kmem_zalloc(sizeof (zfs_cmd_t), KM_SLEEP);
+
+	if (ddi_copyin((void *)(uintptr_t)arg, zc, sizeof (zfs_cmd_t), 0)) {
+		error = -SET_ERROR(EFAULT);
+		goto out;
+	}
+	error = -zfsdev_ioctl_common(vecnum, zc);
+	rc = ddi_copyout(zc, (void *)(uintptr_t)arg, sizeof (zfs_cmd_t), 0);
+	if (error == 0 && rc != 0)
+		error = -SET_ERROR(EFAULT);
+out:
+	kmem_free(zc, sizeof (zfs_cmd_t));
+	return (error);
+
 }
 
 int
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index 902c0b2b2..a993d02e1 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -7215,18 +7215,19 @@ zfsdev_minor_alloc(void)
 }
 
 long
-zfsdev_ioctl_common(uint_t vecnum, unsigned long arg)
+zfsdev_ioctl_common(uint_t vecnum, zfs_cmd_t *zc)
 {
-	zfs_cmd_t *zc;
-	int error, cmd, rc, flag = 0;
+	int error, cmd, flag = 0;
 	const zfs_ioc_vec_t *vec;
 	char *saved_poolname = NULL;
 	nvlist_t *innvl = NULL;
 	fstrans_cookie_t cookie;
 
 	cmd = vecnum;
+	error = 0;
 	if (vecnum >= sizeof (zfs_ioc_vec) / sizeof (zfs_ioc_vec[0]))
-		return (-SET_ERROR(ZFS_ERR_IOC_CMD_UNAVAIL));
+		return (SET_ERROR(ZFS_ERR_IOC_CMD_UNAVAIL));
+
 	vec = &zfs_ioc_vec[vecnum];
 
 	/*
@@ -7234,16 +7235,7 @@ zfsdev_ioctl_common(uint_t vecnum, unsigned long arg)
 	 * a normal or legacy handler are registered.
 	 */
 	if (vec->zvec_func == NULL && vec->zvec_legacy_func == NULL)
-		return (-SET_ERROR(ZFS_ERR_IOC_CMD_UNAVAIL));
-
-	zc = kmem_zalloc(sizeof (zfs_cmd_t), KM_SLEEP);
-
-	error = ddi_copyin((void *)(uintptr_t)arg, zc, sizeof (zfs_cmd_t),
-	    flag);
-	if (error != 0) {
-		error = SET_ERROR(EFAULT);
-		goto out;
-	}
+		return (SET_ERROR(ZFS_ERR_IOC_CMD_UNAVAIL));
 
 	zc->zc_iflags = flag & FKIOCTL;
 	if (zc->zc_nvlist_src_size > MAX_NVLIST_SRC_SIZE) {
@@ -7406,9 +7398,6 @@ zfsdev_ioctl_common(uint_t vecnum, unsigned long arg)
 
 out:
 	nvlist_free(innvl);
-	rc = ddi_copyout(zc, (void *)(uintptr_t)arg, sizeof (zfs_cmd_t), flag);
-	if (error == 0 && rc != 0)
-		error = SET_ERROR(EFAULT);
 	if (error == 0 && vec->zvec_allow_log) {
 		char *s = tsd_get(zfs_allow_log_key);
 		if (s != NULL)
@@ -7418,9 +7407,7 @@ out:
 		if (saved_poolname != NULL)
 			kmem_strfree(saved_poolname);
 	}
-
-	kmem_free(zc, sizeof (zfs_cmd_t));
-	return (-error);
+	return (error);
 }
 
 int