1 files changed, 82 insertions, 24 deletions

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index b3b359660082..29f8599e6bea 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -1,6 +1,7 @@
 #ifndef _LINUX_RING_BUFFER_H
 #define _LINUX_RING_BUFFER_H
 
+#include <linux/kmemcheck.h>
 #include <linux/mm.h>
 #include <linux/seq_file.h>
 
@@ -8,20 +9,27 @@ struct ring_buffer;
 struct ring_buffer_iter;
 
 /*
- * Don't reference this struct directly, use functions below.
+ * Don't refer to this struct directly, use functions below.
  */
 struct ring_buffer_event {
-        u32             type:2, len:3, time_delta:27;
+        kmemcheck_bitfield_begin(bitfield);
+        u32             type_len:5, time_delta:27;
+        kmemcheck_bitfield_end(bitfield);
+
         u32             array[];
 };
 
 /**
  * enum ring_buffer_type - internal ring buffer types
  *
- * @RINGBUF_TYPE_PADDING:       Left over page padding
- *                               array is ignored
- *                               size is variable depending on how much
+ * @RINGBUF_TYPE_PADDING:       Left over page padding or discarded event
+ *                               If time_delta is 0:
+ *                                array is ignored
+ *                                size is variable depending on how much
  *                                padding is needed
+ *                               If time_delta is non zero:
+ *                                array[0] holds the actual length
+ *                                size = 4 + length (bytes)
  *
  * @RINGBUF_TYPE_TIME_EXTEND:   Extend the time delta
  *                               array[0] = time delta (28 .. 59)
@@ -32,22 +40,23 @@ struct ring_buffer_event {
  *                               array[1..2] = tv_sec
  *                               size = 16 bytes
  *
- * @RINGBUF_TYPE_DATA:          Data record
- *                               If len is zero:
+ * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
+ *                              Data record
+ *                               If type_len is zero:
  *                                array[0] holds the actual length
  *                                array[1..(length+3)/4] holds data
- *                                size = 4 + 4 + length (bytes)
+ *                                size = 4 + length (bytes)
  *                               else
- *                                length = len << 2
+ *                                length = type_len << 2
  *                                array[0..(length+3)/4-1] holds data
  *                                size = 4 + length (bytes)
  */
 enum ring_buffer_type {
+        RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
         RINGBUF_TYPE_PADDING,
         RINGBUF_TYPE_TIME_EXTEND,
         /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
         RINGBUF_TYPE_TIME_STAMP,
-        RINGBUF_TYPE_DATA,
 };
 
 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
@@ -66,21 +75,61 @@ ring_buffer_event_time_delta(struct ring_buffer_event *event)
 }
 
 /*
+ * ring_buffer_event_discard can discard any event in the ring buffer.
+ *   it is up to the caller to protect against a reader from
+ *   consuming it or a writer from wrapping and replacing it.
+ *
+ * No external protection is needed if this is called before
+ * the event is commited. But in that case it would be better to
+ * use ring_buffer_discard_commit.
+ *
+ * Note, if an event that has not been committed is discarded
+ * with ring_buffer_event_discard, it must still be committed.
+ */
+void ring_buffer_event_discard(struct ring_buffer_event *event);
+
+/*
+ * ring_buffer_discard_commit will remove an event that has not
+ *   ben committed yet. If this is used, then ring_buffer_unlock_commit
+ *   must not be called on the discarded event. This function
+ *   will try to remove the event from the ring buffer completely
+ *   if another event has not been written after it.
+ *
+ * Example use:
+ *
+ *  if (some_condition)
+ *    ring_buffer_discard_commit(buffer, event);
+ *  else
+ *    ring_buffer_unlock_commit(buffer, event);
+ */
+void ring_buffer_discard_commit(struct ring_buffer *buffer,
+                                struct ring_buffer_event *event);
+
+/*
  * size is in bytes for each per CPU buffer.
  */
 struct ring_buffer *
-ring_buffer_alloc(unsigned long size, unsigned flags);
+__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
+
+/*
+ * Because the ring buffer is generic, if other users of the ring buffer get
+ * traced by ftrace, it can produce lockdep warnings. We need to keep each
+ * ring buffer's lock class separate.
+ */
+#define ring_buffer_alloc(size, flags)                  \
+({                                                      \
+        static struct lock_class_key __key;             \
+        __ring_buffer_alloc((size), (flags), &__key);   \
+})
+
 void ring_buffer_free(struct ring_buffer *buffer);
 
 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
 
-struct ring_buffer_event *
-ring_buffer_lock_reserve(struct ring_buffer *buffer,
-                         unsigned long length,
-                         unsigned long *flags);
+struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
+                                                   unsigned long length);
 int ring_buffer_unlock_commit(struct ring_buffer *buffer,
-                              struct ring_buffer_event *event,
-                              unsigned long flags);
+                              struct ring_buffer_event *event);
 int ring_buffer_write(struct ring_buffer *buffer,
                       unsigned long length, void *data);
 
@@ -120,18 +169,27 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer);
 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
+unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
+unsigned long ring_buffer_nmi_dropped_cpu(struct ring_buffer *buffer, int cpu);
+
+u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
+void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
+                                      int cpu, u64 *ts);
+void ring_buffer_set_clock(struct ring_buffer *buffer,
+                           u64 (*clock)(void));
 
-u64 ring_buffer_time_stamp(int cpu);
-void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
+size_t ring_buffer_page_len(void *page);
 
-void tracing_on(void);
-void tracing_off(void);
-void tracing_off_permanent(void);
 
 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
-int ring_buffer_read_page(struct ring_buffer *buffer,
-                          void **data_page, int cpu, int full);
+int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
+                          size_t len, int cpu, int full);
+
+struct trace_seq;
+
+int ring_buffer_print_entry_header(struct trace_seq *s);
+int ring_buffer_print_page_header(struct trace_seq *s);
 
 enum ring_buffer_flags {
         RB_FL_OVERWRITE         = 1 << 0,