VFS: factor out three helpers for FIBMAP/FIONBIO/FIOASYNC file ioctls

Factor out file-specific ioctl code into smaller helper functions, away from
file_ioctl().  This helps code readability and also reduces indentation inside
case statements.
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ioctl.c

@@ -52,32 +52,34 @@ long vfs_ioctl(struct file *filp, unsigned int cmd,
 	return error;
 }
 
-static int file_ioctl(struct file *filp, unsigned int cmd,
-		unsigned long arg)
+static int ioctl_fibmap(struct file *filp, int __user *p)
 {
-	int error;
-	int block;
-	struct inode *inode = filp->f_path.dentry->d_inode;
-	int __user *p = (int __user *)arg;
-
-	switch (cmd) {
-	case FIBMAP:
-	{
 	struct address_space *mapping = filp->f_mapping;
-		int res;
+	int res, block;
+
 	/* do we support this mess? */
 	if (!mapping->a_ops->bmap)
 		return -EINVAL;
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
-		error = get_user(block, p);
-		if (error)
-			return error;
+	res = get_user(block, p);
+	if (res)
+		return res;
 	lock_kernel();
 	res = mapping->a_ops->bmap(mapping, block);
 	unlock_kernel();
 	return put_user(res, p);
-	}
+}
+
+static int file_ioctl(struct file *filp, unsigned int cmd,
+		unsigned long arg)
+{
+	struct inode *inode = filp->f_path.dentry->d_inode;
+	int __user *p = (int __user *)arg;
+
+	switch (cmd) {
+	case FIBMAP:
+		return ioctl_fibmap(filp, p);
 	case FIGETBSZ:
 		return put_user(inode->i_sb->s_blocksize, p);
 	case FIONREAD:
@@ -87,32 +89,14 @@ static int file_ioctl(struct file *filp, unsigned int cmd,
 	return vfs_ioctl(filp, cmd, arg);
 }
 
-/*
- * When you add any new common ioctls to the switches above and below
- * please update compat_sys_ioctl() too.
- *
- * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
- * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
- */
-int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
-	     unsigned long arg)
+static int ioctl_fionbio(struct file *filp, int __user *argp)
 {
 	unsigned int flag;
-	int on, error = 0;
-
-	switch (cmd) {
-	case FIOCLEX:
-		set_close_on_exec(fd, 1);
-		break;
-
-	case FIONCLEX:
-		set_close_on_exec(fd, 0);
-		break;
+	int on, error;
 
-	case FIONBIO:
-		error = get_user(on, (int __user *)arg);
+	error = get_user(on, argp);
 	if (error)
-			break;
+		return error;
 	flag = O_NONBLOCK;
 #ifdef __sparc__
 	/* SunOS compatibility item. */
@@ -123,12 +107,18 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 		filp->f_flags |= flag;
 	else
 		filp->f_flags &= ~flag;
-		break;
+	return error;
+}
 
-	case FIOASYNC:
-		error = get_user(on, (int __user *)arg);
+static int ioctl_fioasync(unsigned int fd, struct file *filp,
+			  int __user *argp)
+{
+	unsigned int flag;
+	int on, error;
+
+	error = get_user(on, argp);
 	if (error)
-			break;
+		return error;
 	flag = on ? FASYNC : 0;
 
 	/* Did FASYNC state change ? */
@@ -140,13 +130,44 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
 		} else
 			error = -ENOTTY;
 	}
-		if (error != 0)
-			break;
+	if (error)
+		return error;
 
 	if (on)
 		filp->f_flags |= FASYNC;
 	else
 		filp->f_flags &= ~FASYNC;
+	return error;
+}
+
+/*
+ * When you add any new common ioctls to the switches above and below
+ * please update compat_sys_ioctl() too.
+ *
+ * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d.
+ * It's just a simple helper for sys_ioctl and compat_sys_ioctl.
+ */
+int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
+	     unsigned long arg)
+{
+	int error = 0;
+	int __user *argp = (int __user *)arg;
+
+	switch (cmd) {
+	case FIOCLEX:
+		set_close_on_exec(fd, 1);
+		break;
+
+	case FIONCLEX:
+		set_close_on_exec(fd, 0);
+		break;
+
+	case FIONBIO:
+		error = ioctl_fionbio(filp, argp);
+		break;
+
+	case FIOASYNC:
+		error = ioctl_fioasync(fd, filp, argp);
 		break;
 
 	case FIOQSIZE: