[Qemu-devel] [PULL 02/15] seqlock: remove optional mutex

[Richard Henderson <rth@twiddle.net>]

From: "Emilio G. Cota" <cota@braap.org>

This option is unused; besides, it bloats the struct when not needed.
Let's just let writers define their own locks elsewhere.

Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-3-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 cpus.c                 |  2 +-
 include/qemu/seqlock.h | 10 +---------
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/cpus.c b/cpus.c
index 326742f..1c92362 100644
--- a/cpus.c
+++ b/cpus.c
@@ -621,7 +621,7 @@ int cpu_throttle_get_percentage(void)
 
 void cpu_ticks_init(void)
 {
-    seqlock_init(&timers_state.vm_clock_seqlock, NULL);
+    seqlock_init(&timers_state.vm_clock_seqlock);
     vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
     throttle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT,
                                            cpu_throttle_timer_tick, NULL);
diff --git a/include/qemu/seqlock.h b/include/qemu/seqlock.h
index 70b01fd..e673482 100644
--- a/include/qemu/seqlock.h
+++ b/include/qemu/seqlock.h
@@ -19,22 +19,17 @@
 typedef struct QemuSeqLock QemuSeqLock;
 
 struct QemuSeqLock {
-    QemuMutex *mutex;
     unsigned sequence;
 };
 
-static inline void seqlock_init(QemuSeqLock *sl, QemuMutex *mutex)
+static inline void seqlock_init(QemuSeqLock *sl)
 {
-    sl->mutex = mutex;
     sl->sequence = 0;
 }
 
 /* Lock out other writers and update the count.  */
 static inline void seqlock_write_lock(QemuSeqLock *sl)
 {
-    if (sl->mutex) {
-        qemu_mutex_lock(sl->mutex);
-    }
     ++sl->sequence;
 
     /* Write sequence before updating other fields.  */
@@ -47,9 +42,6 @@ static inline void seqlock_write_unlock(QemuSeqLock *sl)
     smp_wmb();
 
     ++sl->sequence;
-    if (sl->mutex) {
-        qemu_mutex_unlock(sl->mutex);
-    }
 }
 
 static inline unsigned seqlock_read_begin(QemuSeqLock *sl)
-- 
2.5.5