[PATCH 01/11] tracing: add entry size to iterator

Steven Rostedt
2009-06-10T17:00:13Z

[-- Attachment #1: 0001-tracing-add-entry-size-to-iterator.patch --]
[-- Type: text/plain, Size: 3751 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

In order to test against corruption of records, the size of the entry
needs to be passed to callbacks. This patch places the entry size
into a new field of the iterator "ent_size", that print call backs
can access.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
include/linux/ftrace_event.h | 1 +
kernel/trace/trace.c | 39 ++++++++++++++++++++++++---------------
2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 5c093ff..c03befb 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -56,6 +56,7 @@ struct trace_iterator {
/* The below is zeroed out in pipe_read */
struct trace_seq seq;
struct trace_entry *ent;
+ unsigned int ent_size;
int cpu;
u64 ts;

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index cae34c6..d83036d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1398,7 +1398,7 @@ static void trace_iterator_increment(struct trace_iterator *iter)
ftrace_enable_cpu();
}

-static struct trace_entry *
+static struct ring_buffer_event *
peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
{
struct ring_buffer_event *event;
@@ -1414,15 +1414,17 @@ peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)

ftrace_enable_cpu();

- return event ? ring_buffer_event_data(event) : NULL;
+ return event;
}

static struct trace_entry *
-__find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
+__find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts,
+ unsigned int *ent_size)
{
struct ring_buffer *buffer = iter->tr->buffer;
- struct trace_entry *ent, *next = NULL;
+ struct ring_buffer_event *event, *next = NULL;
int cpu_file = iter->cpu_file;
+ struct trace_entry *ent;
u64 next_ts = 0, ts;
int next_cpu = -1;
int cpu;
@@ -1434,11 +1436,9 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
if (cpu_file > TRACE_PIPE_ALL_CPU) {
if (ring_buffer_empty_cpu(buffer, cpu_file))
return NULL;
- ent = peek_next_entry(iter, cpu_file, ent_ts);
- if (ent_cpu)
- *ent_cpu = cpu_file;
-
- return ent;
+ next_cpu = cpu_file;
+ next = peek_next_entry(iter, cpu_file, &next_ts);
+ goto out;
}

for_each_tracing_cpu(cpu) {
@@ -1446,38 +1446,47 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
if (ring_buffer_empty_cpu(buffer, cpu))
continue;

- ent = peek_next_entry(iter, cpu, &ts);
+ event = peek_next_entry(iter, cpu, &ts);

/*
* Pick the entry with the smallest timestamp:
*/
- if (ent && (!next || ts < next_ts)) {
- next = ent;
+ if (event && (!next || ts < next_ts)) {
+ next = event;
next_cpu = cpu;
next_ts = ts;
}
}

+ out:
if (ent_cpu)
*ent_cpu = next_cpu;

if (ent_ts)
*ent_ts = next_ts;

- return next;
+ if (!next)
+ return NULL;
+
+ ent = ring_buffer_event_data(next);
+ if (ent_size)
+ *ent_size = ring_buffer_event_length(next);
+
+ return ent;
}

/* Find the next real entry, without updating the iterator itself */
struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
int *ent_cpu, u64 *ent_ts)
{
- return __find_next_entry(iter, ent_cpu, ent_ts);
+ return __find_next_entry(iter, ent_cpu, ent_ts, NULL);
}

/* Find the next real entry, and increment the iterator to the next entry */
static void *find_next_entry_inc(struct trace_iterator *iter)
{
- iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
+ iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts,
+ &iter->ent_size);

if (iter->ent)
trace_iterator_increment(iter);
--
1.6.3.1

--