int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
struct lttng_consumer_local_data *ctx)
{
- unsigned long len;
+ unsigned long len, subbuf_size, padding;
int err;
long ret = 0;
struct lttng_ust_shm_handle *handle;
/* Get the next subbuffer */
err = ustctl_get_next_subbuf(handle, buf);
if (err != 0) {
- ret = -err; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
+ ret = err; /* ustctl_get_next_subbuf returns negative, caller expect positive. */
/*
* This is a debug message even for single-threaded consumer,
* because poll() have more relaxed criterions than get subbuf,
goto end;
}
assert(stream->output == LTTNG_EVENT_MMAP);
- /* read the used subbuffer size */
+ /* Get the full padded subbuffer size */
err = ustctl_get_padded_subbuf_size(handle, buf, &len);
assert(err == 0);
+
+ /* Get subbuffer data size (without padding) */
+ err = ustctl_get_subbuf_size(handle, buf, &subbuf_size);
+ assert(err == 0);
+
+ /* Make sure we don't get a subbuffer size bigger than the padded */
+ assert(len >= subbuf_size);
+
+ padding = len - subbuf_size;
/* write the subbuffer to the tracefile */
- ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
- if (ret != len) {
+ ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
+ if (ret != subbuf_size) {
/*
* display the error but continue processing to try
* to release the subbuffer