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Commit f4b477c4 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by Linus Torvalds
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rbtree: add const qualifier to some functions 



The 'rb_first()', 'rb_last()', 'rb_next()' and 'rb_prev()' calls
take a pointer to an RB node or RB root. They do not change the
pointed objects, so add a 'const' qualifier in order to make life
of the users of these functions easier.

Indeed, if I have my own constant pointer &const struct my_type *p,
and I call 'rb_next(&p->rb)', I get a GCC warning:

warning: passing argument 1 of ‘rb_next’ discards qualifiers from pointer target type

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cfce41a6

include/linux/rbtree.h

+4 −4
Original line number Diff line number Diff line
@@ -140,10 +140,10 @@ extern void rb_insert_color(struct rb_node *, struct rb_root *); 
extern void rb_erase(struct rb_node *, struct rb_root *);



/* Find logical next and previous nodes in a tree */

extern struct rb_node *rb_next(struct rb_node *);

extern struct rb_node *rb_prev(struct rb_node *);

extern struct rb_node *rb_first(struct rb_root *);

extern struct rb_node *rb_last(struct rb_root *);

extern struct rb_node *rb_next(const struct rb_node *);

extern struct rb_node *rb_prev(const struct rb_node *);

extern struct rb_node *rb_first(const struct rb_root *);

extern struct rb_node *rb_last(const struct rb_root *);



/* Fast replacement of a single node without remove/rebalance/add/rebalance */

extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,

lib/rbtree.c

+6 −6
Original line number Diff line number Diff line
@@ -292,7 +292,7 @@ EXPORT_SYMBOL(rb_erase); 
/*

 * This function returns the first node (in sort order) of the tree.

 */

struct rb_node *rb_first(struct rb_root *root)

struct rb_node *rb_first(const struct rb_root *root)

{

	struct rb_node	*n;
@@ -305,7 +305,7 @@ struct rb_node *rb_first(struct rb_root *root) 
}

EXPORT_SYMBOL(rb_first);



struct rb_node *rb_last(struct rb_root *root)

struct rb_node *rb_last(const struct rb_root *root)

{

	struct rb_node	*n;
@@ -318,7 +318,7 @@ struct rb_node *rb_last(struct rb_root *root) 
}

EXPORT_SYMBOL(rb_last);



struct rb_node *rb_next(struct rb_node *node)

struct rb_node *rb_next(const struct rb_node *node)

{

	struct rb_node *parent;
@@ -331,7 +331,7 @@ struct rb_node *rb_next(struct rb_node *node) 
		node = node->rb_right; 

		while (node->rb_left)

			node=node->rb_left;

		return node;

		return (struct rb_node *)node;

	}



	/* No right-hand children.  Everything down and left is
@@ -347,7 +347,7 @@ struct rb_node *rb_next(struct rb_node *node) 
}

EXPORT_SYMBOL(rb_next);



struct rb_node *rb_prev(struct rb_node *node)

struct rb_node *rb_prev(const struct rb_node *node)

{

	struct rb_node *parent;
@@ -360,7 +360,7 @@ struct rb_node *rb_prev(struct rb_node *node) 
		node = node->rb_left; 

		while (node->rb_right)

			node=node->rb_right;

		return node;

		return (struct rb_node *)node;

	}



	/* No left-hand children. Go up till we find an ancestor which