[RFC PATCH 5/6] fs: fat: move fstrim to file_operation

["Enrico Weigelt, metux IT consult" <info@metux.net>]

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/fat/file.c | 25 ++++---------------------
 1 file changed, 4 insertions(+), 21 deletions(-)

diff --git a/fs/fat/file.c b/fs/fat/file.c
index 13855ba49cd9..5f57f06341d0 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -122,35 +122,20 @@ static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr)
 	return put_user(sbi->vol_id, user_attr);
 }
 
-static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg)
+static int fat_ioctl_fitrim(struct file *file, struct fstrim_range *range)
 {
+	struct inode *inode = file_inode(file);
 	struct super_block *sb = inode->i_sb;
-	struct fstrim_range __user *user_range;
-	struct fstrim_range range;
 	struct request_queue *q = bdev_get_queue(sb->s_bdev);
 	int err;
 
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
-
 	if (!blk_queue_discard(q))
 		return -EOPNOTSUPP;
 
-	user_range = (struct fstrim_range __user *)arg;
-	if (copy_from_user(&range, user_range, sizeof(range)))
-		return -EFAULT;
-
-	range.minlen = max_t(unsigned int, range.minlen,
+	range->minlen = max_t(unsigned int, range->minlen,
 			     q->limits.discard_granularity);
 
-	err = fat_trim_fs(inode, &range);
-	if (err < 0)
-		return err;
-
-	if (copy_to_user(user_range, &range, sizeof(range)))
-		return -EFAULT;
-
-	return 0;
+	return fat_trim_fs(inode, range);
 }
 
 long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
@@ -165,8 +150,6 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return fat_ioctl_set_attributes(filp, user_attr);
 	case FAT_IOCTL_GET_VOLUME_ID:
 		return fat_ioctl_get_volume_id(inode, user_attr);
-	case FITRIM:
-		return fat_ioctl_fitrim(inode, arg);
 	default:
 		return -ENOTTY;	/* Inappropriate ioctl for device */
 	}
-- 
2.20.1