[Qemu-devel] [PATCH 6/8] timers: introduce cpu_get_clock_locked

[Paolo Bonzini]

This fixes a deadlock in cpu_disable_ticks.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
        Should be squashed in Ping Fan's patches.

 cpus.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/cpus.c b/cpus.c
index 08eaf23..01acce2 100644
--- a/cpus.c
+++ b/cpus.c
@@ -166,6 +166,20 @@ int64_t cpu_get_ticks(void)
     }
 }
 
+static int64_t cpu_get_clock_locked(void)
+{
+    int64_t ti;
+
+    if (!timers_state.cpu_ticks_enabled) {
+        ti = timers_state.cpu_clock_offset;
+    } else {
+        ti = get_clock();
+        ti += timers_state.cpu_clock_offset;
+    }
+
+    return ti;
+}
+
 /* return the host CPU monotonic timer and handle stop/restart */
 int64_t cpu_get_clock(void)
 {
@@ -174,12 +188,7 @@ int64_t cpu_get_clock(void)
 
     do {
         start = seqlock_read_begin(&timers_state.clock_seqlock);
-        if (!timers_state.cpu_ticks_enabled) {
-            ti = timers_state.cpu_clock_offset;
-        } else {
-            ti = get_clock();
-            ti += timers_state.cpu_clock_offset;
-        }
+        ti = cpu_get_clock_locked();
     } while (seqlock_read_retry(&timers_state.clock_seqlock, start));
 
     return ti;
@@ -220,7 +233,7 @@ void cpu_disable_ticks(void)
     seqlock_write_lock(&timers_state.clock_seqlock);
     if (timers_state.cpu_ticks_enabled) {
         timers_state.cpu_ticks_offset = cpu_get_ticks();
-        timers_state.cpu_clock_offset = cpu_get_clock();
+        timers_state.cpu_clock_offset = cpu_get_clock_locked();
         timers_state.cpu_ticks_enabled = 0;
     }
     seqlock_write_unlock(&timers_state.clock_seqlock);
-- 
1.8.3.1