trace_uuid -> uuid

[lttng-modules.git] / ltt-events.c

diff --git a/ltt-events.c b/ltt-events.c
index db1ac86fef6573645fc42edd0ae46f32fcfbd333..1aadd9f37faffafef8776bf23abc5d4726238693 100644 (file)
--- a/ltt-events.c
+++ b/ltt-events.c
@@ -287,6 +287,12 @@ void _ltt_event_destroy(struct ltt_event *event)
        kmem_cache_free(event_cache, event);
 }
 
+/*
+ * We have exclusive access to our metadata buffer (protected by the
+ * sessions_mutex), so we can do racy operations such as looking for
+ * remaining space left in packet and write, since mutual exclusion
+ * protects us from concurrent writes.
+ */
 int lttng_metadata_printf(struct ltt_session *session,
                          const char *fmt, ...)
 {
@@ -294,7 +300,7 @@ int lttng_metadata_printf(struct ltt_session *session,
        struct ltt_channel *chan = session->metadata;
        char *str;
        int ret = 0, waitret;
-       size_t len;
+       size_t len, reserve_len, pos;
        va_list ap;
 
        WARN_ON_ONCE(!ACCESS_ONCE(session->active));
@@ -305,30 +311,38 @@ int lttng_metadata_printf(struct ltt_session *session,
        if (!str)
                return -ENOMEM;
 
-       len = strlen(str) + 1;
-       lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, len, sizeof(char), -1);
-       /*
-        * We don't care about metadata buffer's records lost count, because we
-        * always retry here. Report error if we need to bail out after timeout
-        * or being interrupted.
-        */
-       waitret = wait_event_interruptible_timeout(*chan->ops->get_reader_wait_queue(chan),
-               ({
-                       ret = chan->ops->event_reserve(&ctx);
-                       ret != -ENOBUFS || !ret;
-               }),
-               msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC));
-       if (!waitret || waitret == -ERESTARTSYS || ret) {
-               printk(KERN_WARNING "LTTng: Failure to write metadata to buffers (%s)\n",
-                       waitret == -ERESTARTSYS ? "interrupted" :
-                               (ret == -ENOBUFS ? "timeout" : "I/O error"));
-               printk("waitret %d retval %d\n", waitret, ret);
-               if (waitret == -ERESTARTSYS)
-                       ret = waitret;
-               goto end;
+       len = strlen(str);
+       pos = 0;
+
+       for (pos = 0; pos < len; pos += reserve_len) {
+               reserve_len = min_t(size_t,
+                               chan->ops->packet_avail_size(chan->chan),
+                               len - pos);
+               lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, reserve_len,
+                                        sizeof(char), -1);
+               /*
+                * We don't care about metadata buffer's records lost
+                * count, because we always retry here. Report error if
+                * we need to bail out after timeout or being
+                * interrupted.
+                */
+               waitret = wait_event_interruptible_timeout(*chan->ops->get_reader_wait_queue(chan),
+                       ({
+                               ret = chan->ops->event_reserve(&ctx);
+                               ret != -ENOBUFS || !ret;
+                       }),
+                       msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC));
+               if (!waitret || waitret == -ERESTARTSYS || ret) {
+                       printk(KERN_WARNING "LTTng: Failure to write metadata to buffers (%s)\n",
+                               waitret == -ERESTARTSYS ? "interrupted" :
+                                       (ret == -ENOBUFS ? "timeout" : "I/O error"));
+                       if (waitret == -ERESTARTSYS)
+                               ret = waitret;
+                       goto end;
+               }
+               chan->ops->event_write(&ctx, &str[pos], len);
+               chan->ops->event_commit(&ctx);
        }
-       chan->ops->event_write(&ctx, str, len);
-       chan->ops->event_commit(&ctx);
 end:
        kfree(str);
        return ret;
@@ -542,7 +556,7 @@ int _ltt_session_metadata_statedump(struct ltt_session *session)
                "       byte_order = %s;\n"
                "       packet.header := struct {\n"
                "               uint32_t magic;\n"
-               "               uint8_t  trace_uuid[16];\n"
+               "               uint8_t  uuid[16];\n"
                "               uint32_t stream_id;\n"
                "               uint64_t timestamp_begin;\n"
                "               uint64_t timestamp_end;\n"