locking/refcounts: Include fewer headers in <linux/refcount.h>

Debloat <linux/refcount.h>'s dependencies:

- <linux/kernel.h> is not needed, but <linux/compiler.h> is.
- <linux/mutex.h> is not needed, only a forward declaration of "struct mutex".
- <linux/spinlock.h> is not needed, <linux/spinlock_types.h> is enough.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://lkml.kernel.org/lkml/20180331220036.GA7676@avx2
Signed-off-by: Ingo Molnar <mingo@kernel.org>

3 files changed, 7 insertions, 3 deletions

diff --git a/arch/x86/include/asm/refcount.h b/arch/x86/include/asm/refcount.h
index 4cf11d88d3b3..19b90521954c 100644
--- a/arch/x86/include/asm/refcount.h
+++ b/arch/x86/include/asm/refcount.h
@@ -5,6 +5,7 @@
  * PaX/grsecurity.
  */
 #include <linux/refcount.h>
+#include <asm/bug.h>
 
 /*
  * This is the first portion of the refcount error handling, which lives in
diff --git a/include/linux/refcount.h b/include/linux/refcount.h
index 4193c41e383a..c36addd27dd5 100644
--- a/include/linux/refcount.h
+++ b/include/linux/refcount.h
@@ -3,9 +3,10 @@
 #define _LINUX_REFCOUNT_H
 
 #include <linux/atomic.h>
-#include <linux/mutex.h>
-#include <linux/spinlock.h>
-#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <linux/spinlock_types.h>
+
+struct mutex;
 
 /**
  * struct refcount_t - variant of atomic_t specialized for reference counts
diff --git a/lib/refcount.c b/lib/refcount.c
index 0eb48353abe3..4bd842f20749 100644
--- a/lib/refcount.c
+++ b/lib/refcount.c
@@ -35,7 +35,9 @@
  *
  */
 
+#include <linux/mutex.h>
 #include <linux/refcount.h>
+#include <linux/spinlock.h>
 #include <linux/bug.h>
 
 #ifdef CONFIG_REFCOUNT_FULL