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-rw-r--r--kernel/trace/ring_buffer.c29
1 files changed, 20 insertions, 9 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 3632ce87674..c3dab054d18 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -405,7 +405,7 @@ static inline int test_time_stamp(u64 delta)
#define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2))
/* Max number of timestamps that can fit on a page */
-#define RB_TIMESTAMPS_PER_PAGE (BUF_PAGE_SIZE / RB_LEN_TIME_STAMP)
+#define RB_TIMESTAMPS_PER_PAGE (BUF_PAGE_SIZE / RB_LEN_TIME_EXTEND)
int ring_buffer_print_page_header(struct trace_seq *s)
{
@@ -2606,6 +2606,19 @@ void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu)
}
EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
+/*
+ * The total entries in the ring buffer is the running counter
+ * of entries entered into the ring buffer, minus the sum of
+ * the entries read from the ring buffer and the number of
+ * entries that were overwritten.
+ */
+static inline unsigned long
+rb_num_of_entries(struct ring_buffer_per_cpu *cpu_buffer)
+{
+ return local_read(&cpu_buffer->entries) -
+ (local_read(&cpu_buffer->overrun) + cpu_buffer->read);
+}
+
/**
* ring_buffer_entries_cpu - get the number of entries in a cpu buffer
* @buffer: The ring buffer
@@ -2614,16 +2627,13 @@ EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long ret;
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 0;
cpu_buffer = buffer->buffers[cpu];
- ret = (local_read(&cpu_buffer->entries) - local_read(&cpu_buffer->overrun))
- - cpu_buffer->read;
- return ret;
+ return rb_num_of_entries(cpu_buffer);
}
EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
@@ -2684,8 +2694,7 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer)
/* if you care about this being correct, lock the buffer */
for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
- entries += (local_read(&cpu_buffer->entries) -
- local_read(&cpu_buffer->overrun)) - cpu_buffer->read;
+ entries += rb_num_of_entries(cpu_buffer);
}
return entries;
@@ -2985,13 +2994,11 @@ static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)
static void rb_advance_iter(struct ring_buffer_iter *iter)
{
- struct ring_buffer *buffer;
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event;
unsigned length;
cpu_buffer = iter->cpu_buffer;
- buffer = cpu_buffer->buffer;
/*
* Check if we are at the end of the buffer.
@@ -3846,6 +3853,9 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
rpos = reader->read;
pos += size;
+ if (rpos >= commit)
+ break;
+
event = rb_reader_event(cpu_buffer);
size = rb_event_length(event);
} while (len > size);
@@ -3964,6 +3974,7 @@ static const struct file_operations rb_simple_fops = {
.open = tracing_open_generic,
.read = rb_simple_read,
.write = rb_simple_write,
+ .llseek = default_llseek,
};