[PATCH] locking/arch: Move qrwlock.h include after qspinlock.h

Paolo Bonzini
2021-02-10T18:36:49Z

include/asm-generic/qrwlock.h was trying to get arch_spin_is_locked via
asm-generic/qspinlock.h. However, this does not work because architectures
might be using queued rwlocks but not queued spinlocks (csky), or because they
might be defining their own queued_* macros before including asm/qspinlock.h.

To fix this, ensure that asm/spinlock.h always includes qrwlock.h after
defining arch_spin_is_locked (either directly for csky, or via
asm/qspinlock.h for other architectures). The only inclusion elsewhere
is in kernel/locking/qrwlock.c. That one is really unnecessary because
the file is only compiled in SMP configurations (config QUEUED_RWLOCKS
depends on SMP) and in that case linux/spinlock.h already includes
asm/qrwlock.h if needed, via asm/spinlock.h.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Waiman Long <longman@redhat.com>
Fixes: 26128cb6c7e6 ("locking/rwlocks: Add contention detection for rwlocks")
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
v1->v2: Fix sparc too. Add a comment in qrwlock.h itself.
Remove unnecessary inclusion in kernel/locking/qrwlock.c

arch/arm64/include/asm/spinlock.h | 2 +-
arch/mips/include/asm/spinlock.h | 2 +-
arch/sparc/include/asm/spinlock_64.h | 2 +-
arch/xtensa/include/asm/spinlock.h | 2 +-
include/asm-generic/qrwlock.h | 3 ++-
kernel/locking/qrwlock.c | 1 -
6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h
index 9083d6992603..0525c0b089ed 100644
--- a/arch/arm64/include/asm/spinlock.h
+++ b/arch/arm64/include/asm/spinlock.h
@@ -5,8 +5,8 @@
#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H

-#include <asm/qrwlock.h>
#include <asm/qspinlock.h>
+#include <asm/qrwlock.h>

/* See include/linux/spinlock.h */
#define smp_mb__after_spinlock() smp_mb()
diff --git a/arch/mips/include/asm/spinlock.h b/arch/mips/include/asm/spinlock.h
index 8a88eb265516..6ce2117e49f6 100644
--- a/arch/mips/include/asm/spinlock.h
+++ b/arch/mips/include/asm/spinlock.h
@@ -10,7 +10,6 @@
#define _ASM_SPINLOCK_H

#include <asm/processor.h>
-#include <asm/qrwlock.h>

#include <asm-generic/qspinlock_types.h>

@@ -27,5 +26,6 @@ static inline void queued_spin_unlock(struct qspinlock *lock)
}

#include <asm/qspinlock.h>
+#include <asm/qrwlock.h>

#endif /* _ASM_SPINLOCK_H */
diff --git a/arch/sparc/include/asm/spinlock_64.h b/arch/sparc/include/asm/spinlock_64.h
index 7fc82a233f49..3a9a0b0c7465 100644
--- a/arch/sparc/include/asm/spinlock_64.h
+++ b/arch/sparc/include/asm/spinlock_64.h
@@ -11,8 +11,8 @@

#include <asm/processor.h>
#include <asm/barrier.h>
-#include <asm/qrwlock.h>
#include <asm/qspinlock.h>
+#include <asm/qrwlock.h>

#endif /* !(__ASSEMBLY__) */

diff --git a/arch/xtensa/include/asm/spinlock.h b/arch/xtensa/include/asm/spinlock.h
index 584b0de6f2ca..41c449ece2d8 100644
--- a/arch/xtensa/include/asm/spinlock.h
+++ b/arch/xtensa/include/asm/spinlock.h
@@ -12,8 +12,8 @@
#define _XTENSA_SPINLOCK_H

#include <asm/barrier.h>
-#include <asm/qrwlock.h>
#include <asm/qspinlock.h>
+#include <asm/qrwlock.h>

#define smp_mb__after_spinlock() smp_mb()

diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h
index 0020d3b820a7..7ae0ece07b4e 100644
--- a/include/asm-generic/qrwlock.h
+++ b/include/asm-generic/qrwlock.h
@@ -14,7 +14,8 @@
#include <asm/processor.h>

#include <asm-generic/qrwlock_types.h>
-#include <asm-generic/qspinlock.h>
+
+/* Must be included from asm/spinlock.h after defining arch_spin_is_locked. */

/*
* Writer states & reader shift and bias.
diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c
index fe9ca92faa2a..4786dd271b45 100644
--- a/kernel/locking/qrwlock.c
+++ b/kernel/locking/qrwlock.c
@@ -12,7 +12,6 @@
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/spinlock.h>
-#include <asm/qrwlock.h>

/**
* queued_read_lock_slowpath - acquire read lock of a queue rwlock
--
2.26.2