[tip: locking/core] locking: Fix rwlock support in <linux/spinlock_up.h>

[tip-bot2 for Bart Van Assche]

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

Commit-ID:     756a0e011cfca0b45a48464aa25b05d9a9c2fb0b
Gitweb:        https://git.kernel.org/tip/756a0e011cfca0b45a48464aa25b05d9a9c2fb0b
Author:        Bart Van Assche <bvanassche@xxxxxxx>
AuthorDate:    Fri, 13 Mar 2026 10:15:07 -07:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 16 Mar 2026 13:16:50 +01:00

locking: Fix rwlock support in <linux/spinlock_up.h>

Architecture support for rwlocks must be available whether or not
CONFIG_DEBUG_SPINLOCK has been defined. Move the definitions of the
arch_{read,write}_{lock,trylock,unlock}() macros such that these become
visbile if CONFIG_DEBUG_SPINLOCK=n.

This patch prepares for converting do_raw_{read,write}_trylock() into
inline functions. Without this patch that conversion triggers a build
failure for UP architectures, e.g. arm-ep93xx. I used the following
kernel configuration to build the kernel for that architecture:

	CONFIG_ARCH_MULTIPLATFORM=y
	CONFIG_ARCH_MULTI_V7=n
	CONFIG_ATAGS=y
	CONFIG_MMU=y
	CONFIG_ARCH_MULTI_V4T=y
	CONFIG_CPU_LITTLE_ENDIAN=y
	CONFIG_ARCH_EP93XX=y

Fixes: fb1c8f93d869 ("[PATCH] spinlock consolidation")
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://patch.msgid.link/20260313171510.230998-2-bvanassche@xxxxxxx
---
 include/linux/spinlock_up.h | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/linux/spinlock_up.h b/include/linux/spinlock_up.h
index 1e84e71..3a50976 100644
--- a/include/linux/spinlock_up.h
+++ b/include/linux/spinlock_up.h
@@ -48,16 +48,6 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
 	lock->slock = 1;
 }
 
-/*
- * Read-write spinlocks. No debug version.
- */
-#define arch_read_lock(lock)		do { barrier(); (void)(lock); } while (0)
-#define arch_write_lock(lock)		do { barrier(); (void)(lock); } while (0)
-#define arch_read_trylock(lock)	({ barrier(); (void)(lock); 1; })
-#define arch_write_trylock(lock)	({ barrier(); (void)(lock); 1; })
-#define arch_read_unlock(lock)		do { barrier(); (void)(lock); } while (0)
-#define arch_write_unlock(lock)	do { barrier(); (void)(lock); } while (0)
-
 #else /* DEBUG_SPINLOCK */
 #define arch_spin_is_locked(lock)	((void)(lock), 0)
 /* for sched/core.c and kernel_lock.c: */
@@ -68,4 +58,14 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock)
 
 #define arch_spin_is_contended(lock)	(((void)(lock), 0))
 
+/*
+ * Read-write spinlocks. No debug version.
+ */
+#define arch_read_lock(lock)		do { barrier(); (void)(lock); } while (0)
+#define arch_write_lock(lock)		do { barrier(); (void)(lock); } while (0)
+#define arch_read_trylock(lock)	({ barrier(); (void)(lock); 1; })
+#define arch_write_trylock(lock)	({ barrier(); (void)(lock); 1; })
+#define arch_read_unlock(lock)		do { barrier(); (void)(lock); } while (0)
+#define arch_write_unlock(lock)	do { barrier(); (void)(lock); } while (0)
+
 #endif /* __LINUX_SPINLOCK_UP_H */