Adapt lttng-modules to Linux 4.10 cpu hotplug state machine

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

diff --git a/lib/ringbuffer/ring_buffer_iterator.c b/lib/ringbuffer/ring_buffer_iterator.c
index 47e151bfce4c13ed9a525e465e98c17d7bfcfc55..b6bec48d0dfc94e0dd5c3d7337ce0f1d17bd12ae 100644 (file)
--- a/lib/ringbuffer/ring_buffer_iterator.c
+++ b/lib/ringbuffer/ring_buffer_iterator.c
@@ -350,6 +350,25 @@ void lib_ring_buffer_iterator_init(struct channel *chan, struct lib_ring_buffer
                list_add(&buf->iter.empty_node, &chan->iter.empty_head);
 }
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+
+int lttng_cpuhp_rb_iter_online(unsigned int cpu,
+               struct lttng_cpuhp_node *node)
+{
+       struct channel *chan = container_of(node, struct channel,
+                                           cpuhp_iter_online);
+       struct lib_ring_buffer *buf = per_cpu_ptr(chan->backend.buf, cpu);
+       const struct lib_ring_buffer_config *config = &chan->backend.config;
+
+       CHAN_WARN_ON(chan, config->alloc == RING_BUFFER_ALLOC_GLOBAL);
+
+       lib_ring_buffer_iterator_init(chan, buf);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(lttng_cpuhp_rb_iter_online);
+
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+
 #ifdef CONFIG_HOTPLUG_CPU
 static
 int channel_iterator_cpu_hotplug(struct notifier_block *nb,
@@ -380,13 +399,15 @@ int channel_iterator_cpu_hotplug(struct notifier_block *nb,
 }
 #endif
 
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+
 int channel_iterator_init(struct channel *chan)
 {
        const struct lib_ring_buffer_config *config = &chan->backend.config;
        struct lib_ring_buffer *buf;
 
        if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
-               int cpu, ret;
+               int ret;
 
                INIT_LIST_HEAD(&chan->iter.empty_head);
                ret = lttng_heap_init(&chan->iter.heap,
@@ -394,29 +415,43 @@ int channel_iterator_init(struct channel *chan)
                                GFP_KERNEL, buf_is_higher);
                if (ret)
                        return ret;
-               /*
-                * In case of non-hotplug cpu, if the ring-buffer is allocated
-                * in early initcall, it will not be notified of secondary cpus.
-                * In that off case, we need to allocate for all possible cpus.
-                */
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+               chan->cpuhp_iter_online.component = LTTNG_RING_BUFFER_ITER;
+               ret = cpuhp_state_add_instance(lttng_rb_hp_online,
+                       &chan->cpuhp_iter_online.node);
+               if (ret)
+                       return ret;
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
+               {
+                       int cpu;
+
+                       /*
+                        * In case of non-hotplug cpu, if the ring-buffer is allocated
+                        * in early initcall, it will not be notified of secondary cpus.
+                        * In that off case, we need to allocate for all possible cpus.
+                        */
 #ifdef CONFIG_HOTPLUG_CPU
-               chan->hp_iter_notifier.notifier_call =
-                       channel_iterator_cpu_hotplug;
-               chan->hp_iter_notifier.priority = 10;
-               register_cpu_notifier(&chan->hp_iter_notifier);
-               get_online_cpus();
-               for_each_online_cpu(cpu) {
-                       buf = per_cpu_ptr(chan->backend.buf, cpu);
-                       lib_ring_buffer_iterator_init(chan, buf);
-               }
-               chan->hp_iter_enable = 1;
-               put_online_cpus();
+                       chan->hp_iter_notifier.notifier_call =
+                               channel_iterator_cpu_hotplug;
+                       chan->hp_iter_notifier.priority = 10;
+                       register_cpu_notifier(&chan->hp_iter_notifier);
+
+                       get_online_cpus();
+                       for_each_online_cpu(cpu) {
+                               buf = per_cpu_ptr(chan->backend.buf, cpu);
+                               lib_ring_buffer_iterator_init(chan, buf);
+                       }
+                       chan->hp_iter_enable = 1;
+                       put_online_cpus();
 #else
-               for_each_possible_cpu(cpu) {
-                       buf = per_cpu_ptr(chan->backend.buf, cpu);
-                       lib_ring_buffer_iterator_init(chan, buf);
-               }
+                       for_each_possible_cpu(cpu) {
+                               buf = per_cpu_ptr(chan->backend.buf, cpu);
+                               lib_ring_buffer_iterator_init(chan, buf);
+                       }
 #endif
+               }
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
        } else {
                buf = channel_get_ring_buffer(config, chan, 0);
                lib_ring_buffer_iterator_init(chan, buf);
@@ -429,8 +464,18 @@ void channel_iterator_unregister_notifiers(struct channel *chan)
        const struct lib_ring_buffer_config *config = &chan->backend.config;
 
        if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0))
+               {
+                       int ret;
+
+                       ret = cpuhp_state_remove_instance(lttng_rb_hp_online,
+                               &chan->cpuhp_iter_online.node);
+                       WARN_ON(ret);
+               }
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
                chan->hp_iter_enable = 0;
                unregister_cpu_notifier(&chan->hp_iter_notifier);
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,10,0)) */
        }
 }