fs: f2fs: move fstrim to file_operation

Use the newly introduced file_operation callback for FITRIM ioctl.
This removes some common code, eg. permission check, buffer copying,
which is now done by generic vfs code.

fs/f2fs/file.c

@@ -2252,38 +2252,27 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
 	return ret;
 }
 
-static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg)
+static long f2fs_ioc_fitrim(struct file *file, struct fstrim_range *range)
 {
 	struct inode *inode = file_inode(filp);
 	struct super_block *sb = inode->i_sb;
 	struct request_queue *q = bdev_get_queue(sb->s_bdev);
-	struct fstrim_range range;
 	int ret;
 
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
-
 	if (!f2fs_hw_support_discard(F2FS_SB(sb)))
 		return -EOPNOTSUPP;
 
-	if (copy_from_user(&range, (struct fstrim_range __user *)arg,
-				sizeof(range)))
-		return -EFAULT;
-
 	ret = mnt_want_write_file(filp);
 	if (ret)
 		return ret;
 
-	range.minlen = max((unsigned int)range.minlen,
+	range->minlen = max((unsigned int)range->minlen,
 				q->limits.discard_granularity);
-	ret = f2fs_trim_fs(F2FS_SB(sb), &range);
+	ret = f2fs_trim_fs(F2FS_SB(sb), range);
 	mnt_drop_write_file(filp);
 	if (ret < 0)
 		return ret;
 
-	if (copy_to_user((struct fstrim_range __user *)arg, &range,
-				sizeof(range)))
-		return -EFAULT;
 	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
 	return 0;
 }
@@ -4124,8 +4113,6 @@ static long __f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return f2fs_ioc_abort_volatile_write(filp);
 	case F2FS_IOC_SHUTDOWN:
 		return f2fs_ioc_shutdown(filp, arg);
-	case FITRIM:
-		return f2fs_ioc_fitrim(filp, arg);
 	case FS_IOC_SET_ENCRYPTION_POLICY:
 		return f2fs_ioc_set_encryption_policy(filp, arg);
 	case FS_IOC_GET_ENCRYPTION_POLICY:
@@ -4405,7 +4392,6 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case F2FS_IOC_RELEASE_VOLATILE_WRITE:
 	case F2FS_IOC_ABORT_VOLATILE_WRITE:
 	case F2FS_IOC_SHUTDOWN:
-	case FITRIM:
 	case FS_IOC_SET_ENCRYPTION_POLICY:
 	case FS_IOC_GET_ENCRYPTION_PWSALT:
 	case FS_IOC_GET_ENCRYPTION_POLICY:
@@ -4461,4 +4447,5 @@ const struct file_operations f2fs_file_operations = {
 #endif
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
+	.fitrim		= f2fs_ioc_fitrim,
 };