Commit 089050ca authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Ingo Molnar
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rbtree: Split out the rbtree type definitions into <linux/rbtree_types.h> 



So we have this header dependency problem on RT:

 - <linux/rtmutex.h> needs the definition of 'struct rb_root_cached'.
 - <linux/rbtree.h> includes <linux/kernel.h>, which includes <linux/spinlock.h>.

That works nicely for non-RT enabled kernels, but on RT enabled kernels
spinlocks are based on rtmutexes, which creates another circular header
dependency, as <linux/spinlocks.h> will require <linux/rtmutex.h>.

Split out the type definitions and move them into their own header file so
the rtmutex header can include just those.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.542123501@linutronix.de
parent cbcebf5b

include/linux/rbtree.h

+2 −29
Original line number Diff line number Diff line
@@ -17,24 +17,14 @@ 
#ifndef	_LINUX_RBTREE_H

#define	_LINUX_RBTREE_H



#include <linux/rbtree_types.h>



#include <linux/kernel.h>

#include <linux/stddef.h>

#include <linux/rcupdate.h>



struct rb_node {

	unsigned long  __rb_parent_color;

	struct rb_node *rb_right;

	struct rb_node *rb_left;

} __attribute__((aligned(sizeof(long))));

    /* The alignment might seem pointless, but allegedly CRIS needs it */



struct rb_root {

	struct rb_node *rb_node;

};



#define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))



#define RB_ROOT	(struct rb_root) { NULL, }

#define	rb_entry(ptr, type, member) container_of(ptr, type, member)



#define RB_EMPTY_ROOT(root)  (READ_ONCE((root)->rb_node) == NULL)
@@ -112,23 +102,6 @@ static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent 
			typeof(*pos), field); 1; }); \

	     pos = n)



/*

 * Leftmost-cached rbtrees.

 *

 * We do not cache the rightmost node based on footprint

 * size vs number of potential users that could benefit

 * from O(1) rb_last(). Just not worth it, users that want

 * this feature can always implement the logic explicitly.

 * Furthermore, users that want to cache both pointers may

 * find it a bit asymmetric, but that's ok.

 */

struct rb_root_cached {

	struct rb_root rb_root;

	struct rb_node *rb_leftmost;

};



#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }



/* Same as rb_first(), but O(1) */

#define rb_first_cached(root) (root)->rb_leftmost

include/linux/rbtree_types.h

0 → 100644
+34 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-or-later */

#ifndef _LINUX_RBTREE_TYPES_H

#define _LINUX_RBTREE_TYPES_H



struct rb_node {

	unsigned long  __rb_parent_color;

	struct rb_node *rb_right;

	struct rb_node *rb_left;

} __attribute__((aligned(sizeof(long))));

/* The alignment might seem pointless, but allegedly CRIS needs it */



struct rb_root {

	struct rb_node *rb_node;

};



/*

 * Leftmost-cached rbtrees.

 *

 * We do not cache the rightmost node based on footprint

 * size vs number of potential users that could benefit

 * from O(1) rb_last(). Just not worth it, users that want

 * this feature can always implement the logic explicitly.

 * Furthermore, users that want to cache both pointers may

 * find it a bit asymmetric, but that's ok.

 */

struct rb_root_cached {

	struct rb_root rb_root;

	struct rb_node *rb_leftmost;

};



#define RB_ROOT (struct rb_root) { NULL, }

#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }



#endif