Clean-up: consumerd: use a specific status code for get_next_subbuffer

[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 27d346b33f72c2045c698ef432b72da63e967a44..429ab14b1d728a0f15e09872c1763c9c76e0dde4 100644 (file)
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -2890,25 +2890,45 @@ end:
        return ret;
 }
 
-static int get_next_subbuffer(struct lttng_consumer_stream *stream,
+static enum get_next_subbuffer_status get_next_subbuffer(
+               struct lttng_consumer_stream *stream,
                struct stream_subbuffer *subbuffer)
 {
        int ret;
+       enum get_next_subbuffer_status status;
 
        ret = lttng_ust_ctl_get_next_subbuf(stream->ustream);
-       if (ret) {
+       switch (ret) {
+       case 0:
+               status = GET_NEXT_SUBBUFFER_STATUS_OK;
+               break;
+       case -ENODATA:
+               case -EAGAIN:
+               /*
+                * The caller only expects -ENODATA when there is no data to
+                * read, but the kernel tracer returns -EAGAIN when there is
+                * currently no data for a non-finalized stream, and -ENODATA
+                * when there is no data for a finalized stream. Those can be
+                * combined into a -ENODATA return value.
+                */
+               status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
+               goto end;
+       default:
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                goto end;
        }
 
        ret = get_next_subbuffer_common(stream, subbuffer);
        if (ret) {
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                goto end;
        }
 end:
-       return ret;
+       return status;
 }
 
-static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
+static enum get_next_subbuffer_status get_next_subbuffer_metadata(
+               struct lttng_consumer_stream *stream,
                struct stream_subbuffer *subbuffer)
 {
        int ret;
@@ -2917,6 +2937,7 @@ static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
        bool coherent;
        bool buffer_empty;
        unsigned long consumed_pos, produced_pos;
+       enum get_next_subbuffer_status status;
 
        do {
                ret = lttng_ust_ctl_get_next_subbuf(stream->ustream);
@@ -2926,6 +2947,7 @@ static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
                        got_subbuffer = false;
                        if (ret != -EAGAIN) {
                                /* Fatal error. */
+                               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                                goto end;
                        }
                }
@@ -2937,11 +2959,12 @@ static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
                if (!got_subbuffer) {
                        ret = commit_one_metadata_packet(stream);
                        if (ret < 0 && ret != -ENOBUFS) {
+                               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                                goto end;
                        } else if (ret == 0) {
                                /* Not an error, the cache is empty. */
                                cache_empty = true;
-                               ret = -ENODATA;
+                               status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
                                goto end;
                        } else {
                                cache_empty = false;
@@ -2957,6 +2980,7 @@ static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
        /* Populate sub-buffer infos and view. */
        ret = get_next_subbuffer_common(stream, subbuffer);
        if (ret) {
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                goto end;
        }
 
@@ -2967,18 +2991,21 @@ static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
                 * pushed the consumption position yet (on put_next).
                 */
                PERROR("Failed to take a snapshot of metadata buffer positions");
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                goto end;
        }
 
        ret = lttng_ustconsumer_get_consumed_snapshot(stream, &consumed_pos);
        if (ret) {
                PERROR("Failed to get metadata consumed position");
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                goto end;
        }
 
        ret = lttng_ustconsumer_get_produced_snapshot(stream, &produced_pos);
        if (ret) {
                PERROR("Failed to get metadata produced position");
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                goto end;
        }
 
@@ -2994,8 +3021,9 @@ static int get_next_subbuffer_metadata(struct lttng_consumer_stream *stream,
        coherent = got_subbuffer && cache_empty && buffer_empty;
 
        LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
+       status = GET_NEXT_SUBBUFFER_STATUS_OK;
 end:
-       return ret;
+       return status;
 }
 
 static int put_next_subbuffer(struct lttng_consumer_stream *stream,