brlock: fix build with KVM_BRLOCK_DEBUG

Build breaks when using KVM_BRLOCK_DEBUG because the header was seamingly
conceived to be included in a single .c file...

Fix this by moving the definition of the read/write lock into the kvm
struct.
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

include/kvm/brlock.h

@@ -21,13 +21,11 @@
 
 #include "kvm/rwsem.h"
 
-DECLARE_RWSEM(brlock_sem);
+#define br_read_lock(kvm)	down_read(&(kvm)->brlock_sem);
+#define br_read_unlock(kvm)	up_read(&(kvm)->brlock_sem);
 
-#define br_read_lock(kvm)	down_read(&brlock_sem);
-#define br_read_unlock(kvm)	up_read(&brlock_sem);
-
-#define br_write_lock(kvm)	down_write(&brlock_sem);
-#define br_write_unlock(kvm)	up_write(&brlock_sem);
+#define br_write_lock(kvm)	down_write(&(kvm)->brlock_sem);
+#define br_write_unlock(kvm)	up_write(&(kvm)->brlock_sem);
 
 #else
 

include/kvm/kvm.h

@@ -81,6 +81,10 @@ struct kvm {
 	int                     nr_disks;
 
 	int			vm_state;
+
+#ifdef KVM_BRLOCK_DEBUG
+	pthread_rwlock_t	brlock_sem;
+#endif
 };
 
 void kvm__set_dir(const char *fmt, ...);

kvm.c

@@ -160,6 +160,10 @@ struct kvm *kvm__new(void)
 	kvm->sys_fd = -1;
 	kvm->vm_fd = -1;
 
+#ifdef KVM_BRLOCK_DEBUG
+	kvm->brlock_sem = (pthread_rwlock_t) PTHREAD_RWLOCK_INITIALIZER;
+#endif
+
 	return kvm;
 }