[tip: locking/core] locking/rtmutex: Reduce <linux/rtmutex.h> header dependencies, only include <linux/rbtree_types.h>

[tip-bot2 for Sebastian Andrzej Siewior]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     e4e17af3b7f8841279b5a429de14907e26845c39
Gitweb:        https://git.kernel.org/tip/e4e17af3b7f8841279b5a429de14907e26845c39
Author:        Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
AuthorDate:    Sun, 15 Aug 2021 23:28:20 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 17 Aug 2021 17:37:26 +02:00

locking/rtmutex: Reduce <linux/rtmutex.h> header dependencies, only include <linux/rbtree_types.h>

We have the following 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>.

Include <linux/rbtree_types.h> instead.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210815211303.598003167@xxxxxxxxxxxxx
---
 include/linux/rtmutex.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 4be97ae..9deedfe 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -15,7 +15,7 @@
 
 #include <linux/compiler.h>
 #include <linux/linkage.h>
-#include <linux/rbtree.h>
+#include <linux/rbtree_types.h>
 #include <linux/spinlock_types_raw.h>
 
 extern int max_lock_depth; /* for sysctl */