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Commit c682b262 authored by Grant Likely's avatar Grant Likely Committed by Alex Shi
Browse files

of: Drop ->next pointer from struct device_node 



The ->next pointer in struct device_node is a hanger-on from when it was
used to iterate over the whole tree by a particular device_type property
value. Those days are long over, but the fdt unflattening code still
uses it to put nodes in the unflattened tree into the same order as node
in the flat tree. By reworking the unflattening code to reverse the list
after unflattening all the children of a node, the pointer can be
dropped which gives a small amount of memory savings.

Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
Acked-by: default avatarFrank Rowand <frank.rowand@sonymobile.com>
Cc: Gaurav Minocha <gaurav.minocha.os@gmail.com>
(cherry picked from commit 70161ff336674ecfd20614a9c0c61cb17a6e9e83)
Signed-off-by: default avatarAlex Shi <alex.shi@linaro.org>
parent 5ca64887

drivers/of/fdt.c

+18 −6
Original line number Diff line number Diff line
@@ -226,12 +226,8 @@ static void * unflatten_dt_node(void *blob, 
		prev_pp = &np->properties;

		if (dad != NULL) {

			np->parent = dad;

			/* we temporarily use the next field as `last_child'*/

			if (dad->next == NULL)

			np->sibling = dad->child;

			dad->child = np;

			else

				dad->next->sibling = np;

			dad->next = np;

		}

	}

	/* process properties */
@@ -329,6 +325,22 @@ static void * unflatten_dt_node(void *blob, 


	if (*poffset < 0 && *poffset != -FDT_ERR_NOTFOUND)

		pr_err("unflatten: error %d processing FDT\n", *poffset);



	/*

	 * Reverse the child list. Some drivers assumes node order matches .dts

	 * node order

	 */

	if (!dryrun && np->child) {

		struct device_node *child = np->child;

		np->child = NULL;

		while (child) {

			struct device_node *next = child->sibling;

			child->sibling = np->child;

			np->child = child;

			child = next;

		}

	}



	if (nodepp)

		*nodepp = np;

include/linux/of.h

+0 −1
Original line number Diff line number Diff line
@@ -57,7 +57,6 @@ struct device_node { 
	struct	device_node *parent;

	struct	device_node *child;

	struct	device_node *sibling;

	struct	device_node *next;	/* next device of same type */

	struct	kobject kobj;

	unsigned long _flags;

	void	*data;