Tracing fixes for 6.5:

- Fix to /sys/kernel/tracing/per_cpu/cpu*/stats read and entries.
   If a resize shrinks the buffer it clears the read count to notify
   readers that they need to reset. But the read count is also used for
   accounting and this causes the numbers to be off. Instead, create a
   separate variable to use to notify readers to reset.
 
 - Fix the ref counts of the "soft disable" mode. The wrong value was
   used for testing if soft disable mode should be enabled or disable,
   but instead, just change the logic to do the enable and disable
   in place when the SOFT_MODE is set or cleared.
 
 - Several kernel-doc fixes
 
 - Removal of unused external declarations
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Merge tag 'trace-v6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix to /sys/kernel/tracing/per_cpu/cpu*/stats read and entries.

   If a resize shrinks the buffer it clears the read count to notify
   readers that they need to reset. But the read count is also used for
   accounting and this causes the numbers to be off. Instead, create a
   separate variable to use to notify readers to reset.

 - Fix the ref counts of the "soft disable" mode. The wrong value was
   used for testing if soft disable mode should be enabled or disable,
   but instead, just change the logic to do the enable and disable in
   place when the SOFT_MODE is set or cleared.

 - Several kernel-doc fixes

 - Removal of unused external declarations

* tag 'trace-v6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix warning in trace_buffered_event_disable()
  ftrace: Remove unused extern declarations
  tracing: Fix kernel-doc warnings in trace_seq.c
  tracing: Fix kernel-doc warnings in trace_events_trigger.c
  tracing/synthetic: Fix kernel-doc warnings in trace_events_synth.c
  ring-buffer: Fix kernel-doc warnings in ring_buffer.c
  ring-buffer: Fix wrong stat of cpu_buffer->read

include/linux/ftrace.h

@@ -684,7 +684,6 @@ void __init
 ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable);
 
 /* defined in arch */
-extern int ftrace_ip_converted(unsigned long ip);
 extern int ftrace_dyn_arch_init(void);
 extern void ftrace_replace_code(int enable);
 extern int ftrace_update_ftrace_func(ftrace_func_t func);
@@ -859,9 +858,6 @@ static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_a
 }
 #endif
 
-/* May be defined in arch */
-extern int ftrace_arch_read_dyn_info(char *buf, int size);
-
 extern int skip_trace(unsigned long ip);
 extern void ftrace_module_init(struct module *mod);
 extern void ftrace_module_enable(struct module *mod);

kernel/trace/ring_buffer.c

@@ -523,6 +523,8 @@ struct ring_buffer_per_cpu {
 	rb_time_t			before_stamp;
 	u64				event_stamp[MAX_NEST];
 	u64				read_stamp;
+	/* pages removed since last reset */
+	unsigned long			pages_removed;
 	/* ring buffer pages to update, > 0 to add, < 0 to remove */
 	long				nr_pages_to_update;
 	struct list_head		new_pages; /* new pages to add */
@@ -559,6 +561,7 @@ struct ring_buffer_iter {
 	struct buffer_page		*head_page;
 	struct buffer_page		*cache_reader_page;
 	unsigned long			cache_read;
+	unsigned long			cache_pages_removed;
 	u64				read_stamp;
 	u64				page_stamp;
 	struct ring_buffer_event	*event;
@@ -947,6 +950,7 @@ static void rb_wake_up_waiters(struct irq_work *work)
 /**
  * ring_buffer_wake_waiters - wake up any waiters on this ring buffer
  * @buffer: The ring buffer to wake waiters on
+ * @cpu: The CPU buffer to wake waiters on
  *
  * In the case of a file that represents a ring buffer is closing,
  * it is prudent to wake up any waiters that are on this.
@@ -1957,6 +1961,8 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned long nr_pages)
 		to_remove = rb_list_head(to_remove)->next;
 		head_bit |= (unsigned long)to_remove & RB_PAGE_HEAD;
 	}
+	/* Read iterators need to reset themselves when some pages removed */
+	cpu_buffer->pages_removed += nr_removed;
 
 	next_page = rb_list_head(to_remove)->next;
 
@@ -1978,12 +1984,6 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned long nr_pages)
 		cpu_buffer->head_page = list_entry(next_page,
 						struct buffer_page, list);
 
-	/*
-	 * change read pointer to make sure any read iterators reset
-	 * themselves
-	 */
-	cpu_buffer->read = 0;
-
 	/* pages are removed, resume tracing and then free the pages */
 	atomic_dec(&cpu_buffer->record_disabled);
 	raw_spin_unlock_irq(&cpu_buffer->reader_lock);
@@ -3376,7 +3376,6 @@ void ring_buffer_nest_end(struct trace_buffer *buffer)
 /**
  * ring_buffer_unlock_commit - commit a reserved
  * @buffer: The buffer to commit to
- * @event: The event pointer to commit.
  *
  * This commits the data to the ring buffer, and releases any locks held.
  *
@@ -4395,6 +4394,7 @@ static void rb_iter_reset(struct ring_buffer_iter *iter)
 
 	iter->cache_reader_page = iter->head_page;
 	iter->cache_read = cpu_buffer->read;
+	iter->cache_pages_removed = cpu_buffer->pages_removed;
 
 	if (iter->head) {
 		iter->read_stamp = cpu_buffer->read_stamp;
@@ -4849,12 +4849,13 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
 	buffer = cpu_buffer->buffer;
 
 	/*
-	 * Check if someone performed a consuming read to
-	 * the buffer. A consuming read invalidates the iterator
-	 * and we need to reset the iterator in this case.
+	 * Check if someone performed a consuming read to the buffer
+	 * or removed some pages from the buffer. In these cases,
+	 * iterator was invalidated and we need to reset it.
 	 */
 	if (unlikely(iter->cache_read != cpu_buffer->read ||
-		     iter->cache_reader_page != cpu_buffer->reader_page))
+		     iter->cache_reader_page != cpu_buffer->reader_page ||
+		     iter->cache_pages_removed != cpu_buffer->pages_removed))
 		rb_iter_reset(iter);
 
  again:
@@ -5298,6 +5299,7 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
 	cpu_buffer->last_overrun = 0;
 
 	rb_head_page_activate(cpu_buffer);
+	cpu_buffer->pages_removed = 0;
 }
 
 /* Must have disabled the cpu buffer then done a synchronize_rcu */
@@ -5356,7 +5358,6 @@ EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);
 /**
  * ring_buffer_reset_online_cpus - reset a ring buffer per CPU buffer
  * @buffer: The ring buffer to reset a per cpu buffer of
- * @cpu: The CPU buffer to be reset
  */
 void ring_buffer_reset_online_cpus(struct trace_buffer *buffer)
 {

kernel/trace/trace_events.c

@@ -611,7 +611,6 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
 {
 	struct trace_event_call *call = file->event_call;
 	struct trace_array *tr = file->tr;
-	unsigned long file_flags = file->flags;
 	int ret = 0;
 	int disable;
 
@@ -635,6 +634,8 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
 				break;
 			disable = file->flags & EVENT_FILE_FL_SOFT_DISABLED;
 			clear_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
+			/* Disable use of trace_buffered_event */
+			trace_buffered_event_disable();
 		} else
 			disable = !(file->flags & EVENT_FILE_FL_SOFT_MODE);
 
@@ -673,6 +674,8 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
 			if (atomic_inc_return(&file->sm_ref) > 1)
 				break;
 			set_bit(EVENT_FILE_FL_SOFT_MODE_BIT, &file->flags);
+			/* Enable use of trace_buffered_event */
+			trace_buffered_event_enable();
 		}
 
 		if (!(file->flags & EVENT_FILE_FL_ENABLED)) {
@@ -712,15 +715,6 @@ static int __ftrace_event_enable_disable(struct trace_event_file *file,
 		break;
 	}
 
-	/* Enable or disable use of trace_buffered_event */
-	if ((file_flags & EVENT_FILE_FL_SOFT_DISABLED) !=
-	    (file->flags & EVENT_FILE_FL_SOFT_DISABLED)) {
-		if (file->flags & EVENT_FILE_FL_SOFT_DISABLED)
-			trace_buffered_event_enable();
-		else
-			trace_buffered_event_disable();
-	}
-
 	return ret;
 }
 

kernel/trace/trace_events_synth.c

@@ -1230,6 +1230,7 @@ EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
  * @cmd: A pointer to the dynevent_cmd struct representing the new event
  * @name: The name of the synthetic event
+ * @mod: The module creating the event, NULL if not created from a module
  * @fields: An array of type/name field descriptions
  * @n_fields: The number of field descriptions contained in the fields array
  *

kernel/trace/trace_events_trigger.c

@@ -31,7 +31,9 @@ void trigger_data_free(struct event_trigger_data *data)
 /**
  * event_triggers_call - Call triggers associated with a trace event
  * @file: The trace_event_file associated with the event
+ * @buffer: The ring buffer that the event is being written to
  * @rec: The trace entry for the event, NULL for unconditional invocation
+ * @event: The event meta data in the ring buffer
  *
  * For each trigger associated with an event, invoke the trigger
  * function registered with the associated trigger command.  If rec is

kernel/trace/trace_seq.c

@@ -131,6 +131,7 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
  * trace_seq_vprintf - sequence printing of trace information
  * @s: trace sequence descriptor
  * @fmt: printf format string
+ * @args: Arguments for the format string
  *
  * The tracer may use either sequence operations or its own
  * copy to user routines. To simplify formatting of a trace