Merge branch 'wt/lock' into api-hardening

# Conflicts:
#	src/screen.c
#	tests/term_test.c

1 files changed, 4 insertions, 14 deletions

diff --git a/src/internal.h b/src/internal.h
index 5da114d..676413c 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -108,7 +108,8 @@ struct resize_scratch {
 
 
 struct term {
-    _Atomic uint64_t seq;
+    /* The writer section. A waiting thread sleeps on it. */
+    term_mutex write_lock;
     _Atomic uint64_t writer_tid;
     uint32_t write_depth;
     int cols;
@@ -377,18 +378,7 @@ static inline void term_write_begin(struct term *t)
         t->write_depth++;
         return;
     }
-    uint64_t s;
-    for (;;) {
-        s = atomic_load_explicit(&t->seq, memory_order_relaxed);
-        if (s & 1) {
-            term_cpu_relax();
-            continue;
-        }
-        if (atomic_compare_exchange_weak_explicit(&t->seq, &s, s + 1,
-                                                  memory_order_acquire,
-                                                  memory_order_relaxed))
-            break;
-    }
+    term_mutex_lock(&t->write_lock);
     atomic_store_explicit(&t->writer_tid, self, memory_order_relaxed);
     t->write_depth = 1;
 }
@@ -398,7 +388,7 @@ static inline void term_write_end(struct term *t)
     if (!t) return;
     if (--t->write_depth == 0) {
         atomic_store_explicit(&t->writer_tid, 0, memory_order_relaxed);
-        atomic_fetch_add_explicit(&t->seq, 1, memory_order_release);
+        term_mutex_unlock(&t->write_lock);
     }
 }