ext4: keep uniform naming convention for io & io_end variables

Let's keep uniform naming convention for ext4_submit_io (io)
& ext4_end_io_t (io_end) structures, to avoid any confusion.
No functionality change in this patch.

Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20191016073711.4141-2-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/page-io.c

@@ -136,19 +136,19 @@ static void ext4_release_io_end(ext4_io_end_t *io_end)
  * cannot get to ext4_ext_truncate() before all IOs overlapping that range are
  * completed (happens from ext4_free_ioend()).
  */
-static int ext4_end_io(ext4_io_end_t *io)
+static int ext4_end_io_end(ext4_io_end_t *io_end)
 {
-	struct inode *inode = io->inode;
-	loff_t offset = io->offset;
-	ssize_t size = io->size;
-	handle_t *handle = io->handle;
+	struct inode *inode = io_end->inode;
+	loff_t offset = io_end->offset;
+	ssize_t size = io_end->size;
+	handle_t *handle = io_end->handle;
 	int ret = 0;
 
-	ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p,"
+	ext4_debug("ext4_end_io_nolock: io_end 0x%p from inode %lu,list->next 0x%p,"
 		   "list->prev 0x%p\n",
-		   io, inode->i_ino, io->list.next, io->list.prev);
+		   io_end, inode->i_ino, io_end->list.next, io_end->list.prev);
 
-	io->handle = NULL;	/* Following call will use up the handle */
+	io_end->handle = NULL;	/* Following call will use up the handle */
 	ret = ext4_convert_unwritten_extents(handle, inode, offset, size);
 	if (ret < 0 && !ext4_forced_shutdown(EXT4_SB(inode->i_sb))) {
 		ext4_msg(inode->i_sb, KERN_EMERG,
@@ -157,30 +157,30 @@ static int ext4_end_io(ext4_io_end_t *io)
 			 "(inode %lu, offset %llu, size %zd, error %d)",
 			 inode->i_ino, offset, size, ret);
 	}
-	ext4_clear_io_unwritten_flag(io);
-	ext4_release_io_end(io);
+	ext4_clear_io_unwritten_flag(io_end);
+	ext4_release_io_end(io_end);
 	return ret;
 }
 
 static void dump_completed_IO(struct inode *inode, struct list_head *head)
 {
 #ifdef	EXT4FS_DEBUG
 	struct list_head *cur, *before, *after;
-	ext4_io_end_t *io, *io0, *io1;
+	ext4_io_end_t *io_end, *io_end0, *io_end1;
 
 	if (list_empty(head))
 		return;
 
 	ext4_debug("Dump inode %lu completed io list\n", inode->i_ino);
-	list_for_each_entry(io, head, list) {
-		cur = &io->list;
+	list_for_each_entry(io_end, head, list) {
+		cur = &io_end->list;
 		before = cur->prev;
-		io0 = container_of(before, ext4_io_end_t, list);
+		io_end0 = container_of(before, ext4_io_end_t, list);
 		after = cur->next;
-		io1 = container_of(after, ext4_io_end_t, list);
+		io_end1 = container_of(after, ext4_io_end_t, list);
 
 		ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
-			    io, inode->i_ino, io0, io1);
+			    io_end, inode->i_ino, io_end0, io_end1);
 	}
 #endif
 }
@@ -207,7 +207,7 @@ static void ext4_add_complete_io(ext4_io_end_t *io_end)
 static int ext4_do_flush_completed_IO(struct inode *inode,
 				      struct list_head *head)
 {
-	ext4_io_end_t *io;
+	ext4_io_end_t *io_end;
 	struct list_head unwritten;
 	unsigned long flags;
 	struct ext4_inode_info *ei = EXT4_I(inode);
@@ -219,11 +219,11 @@ static int ext4_do_flush_completed_IO(struct inode *inode,
 	spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
 
 	while (!list_empty(&unwritten)) {
-		io = list_entry(unwritten.next, ext4_io_end_t, list);
-		BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN));
-		list_del_init(&io->list);
+		io_end = list_entry(unwritten.next, ext4_io_end_t, list);
+		BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN));
+		list_del_init(&io_end->list);
 
-		err = ext4_end_io(io);
+		err = ext4_end_io_end(io_end);
 		if (unlikely(!ret && err))
 			ret = err;
 	}
@@ -242,13 +242,14 @@ void ext4_end_io_rsv_work(struct work_struct *work)
 
 ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
 {
-	ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags);
-	if (io) {
-		io->inode = inode;
-		INIT_LIST_HEAD(&io->list);
-		atomic_set(&io->count, 1);
+	ext4_io_end_t *io_end = kmem_cache_zalloc(io_end_cachep, flags);
+
+	if (io_end) {
+		io_end->inode = inode;
+		INIT_LIST_HEAD(&io_end->list);
+		atomic_set(&io_end->count, 1);
 	}
-	return io;
+	return io_end;
 }
 
 void ext4_put_io_end_defer(ext4_io_end_t *io_end)