Fix: do not generate packet at destroy after stop

[lttng-modules.git] / lib / ringbuffer / ring_buffer_frontend.c

diff --git a/lib/ringbuffer/ring_buffer_frontend.c b/lib/ringbuffer/ring_buffer_frontend.c
index c4b797ce8af76faf9ba5209d054b89fb42326656..42cf317a01d56482ae07401b8d1d8123b332a1d5 100644 (file)
--- a/lib/ringbuffer/ring_buffer_frontend.c
+++ b/lib/ringbuffer/ring_buffer_frontend.c
@@ -91,6 +91,9 @@ EXPORT_PER_CPU_SYMBOL(lib_ring_buffer_nesting);
 static
 void lib_ring_buffer_print_errors(struct channel *chan,
                                  struct lib_ring_buffer *buf, int cpu);
+static
+void _lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf,
+               enum switch_mode mode);
 
 /*
  * Must be called under cpu hotplug protection.
@@ -585,6 +588,63 @@ static void channel_unregister_notifiers(struct channel *chan)
        channel_backend_unregister_notifiers(&chan->backend);
 }
 
+static void lib_ring_buffer_set_quiescent(struct lib_ring_buffer *buf)
+{
+       if (!buf->quiescent) {
+               buf->quiescent = true;
+               _lib_ring_buffer_switch_remote(buf, SWITCH_FLUSH);
+       }
+}
+
+static void lib_ring_buffer_clear_quiescent(struct lib_ring_buffer *buf)
+{
+       buf->quiescent = false;
+}
+
+void lib_ring_buffer_set_quiescent_channel(struct channel *chan)
+{
+       int cpu;
+       const struct lib_ring_buffer_config *config = &chan->backend.config;
+
+       if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+               get_online_cpus();
+               for_each_channel_cpu(cpu, chan) {
+                       struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf,
+                                                             cpu);
+
+                       lib_ring_buffer_set_quiescent(buf);
+               }
+               put_online_cpus();
+       } else {
+               struct lib_ring_buffer *buf = chan->backend.buf;
+
+               lib_ring_buffer_set_quiescent(buf);
+       }
+}
+EXPORT_SYMBOL_GPL(lib_ring_buffer_set_quiescent_channel);
+
+void lib_ring_buffer_clear_quiescent_channel(struct channel *chan)
+{
+       int cpu;
+       const struct lib_ring_buffer_config *config = &chan->backend.config;
+
+       if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+               get_online_cpus();
+               for_each_channel_cpu(cpu, chan) {
+                       struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf,
+                                                             cpu);
+
+                       lib_ring_buffer_clear_quiescent(buf);
+               }
+               put_online_cpus();
+       } else {
+               struct lib_ring_buffer *buf = chan->backend.buf;
+
+               lib_ring_buffer_clear_quiescent(buf);
+       }
+}
+EXPORT_SYMBOL_GPL(lib_ring_buffer_clear_quiescent_channel);
+
 static void channel_free(struct channel *chan)
 {
        if (chan->backend.release_priv_ops) {
@@ -745,7 +805,7 @@ void *channel_destroy(struct channel *chan)
                                                           chan->backend.priv,
                                                           cpu);
                        if (buf->backend.allocated)
-                               lib_ring_buffer_switch_slow(buf, SWITCH_FLUSH);
+                               lib_ring_buffer_set_quiescent(buf);
                        /*
                         * Perform flush before writing to finalized.
                         */
@@ -759,7 +819,7 @@ void *channel_destroy(struct channel *chan)
                if (config->cb.buffer_finalize)
                        config->cb.buffer_finalize(buf, chan->backend.priv, -1);
                if (buf->backend.allocated)
-                       lib_ring_buffer_switch_slow(buf, SWITCH_FLUSH);
+                       lib_ring_buffer_set_quiescent(buf);
                /*
                 * Perform flush before writing to finalized.
                 */
@@ -1546,7 +1606,8 @@ static void remote_switch(void *info)
        lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 }
 
-void lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf)
+static void _lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf,
+               enum switch_mode mode)
 {
        struct channel *chan = buf->backend.chan;
        const struct lib_ring_buffer_config *config = &chan->backend.config;
@@ -1556,7 +1617,7 @@ void lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf)
         * With global synchronization we don't need to use the IPI scheme.
         */
        if (config->sync == RING_BUFFER_SYNC_GLOBAL) {
-               lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
+               lib_ring_buffer_switch_slow(buf, mode);
                return;
        }
 
@@ -1575,10 +1636,15 @@ void lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf)
                                 remote_switch, buf, 1);
        if (ret) {
                /* Remote CPU is offline, do it ourself. */
-               lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
+               lib_ring_buffer_switch_slow(buf, mode);
        }
        put_online_cpus();
 }
+
+void lib_ring_buffer_switch_remote(struct lib_ring_buffer *buf)
+{
+       _lib_ring_buffer_switch_remote(buf, SWITCH_ACTIVE);
+}
 EXPORT_SYMBOL_GPL(lib_ring_buffer_switch_remote);
 
 /*