[PATCH v3 16/17] tracing output: use new hashtable implementation

[Sasha Levin]

Switch tracing to use the new hashtable implementation. This reduces the amount 
of
generic unrelated code in the tracing module.

Signed-off-by: Sasha Levin <levinsasha...@gmail.com>
---
 kernel/trace/trace_output.c |   20 ++++++++------------
 1 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 123b189..1324c1a 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -8,15 +8,15 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/ftrace.h>
+#include <linux/hashtable.h>
 
 #include "trace_output.h"
 
-/* must be a power of 2 */
-#define EVENT_HASHSIZE 128
+#define EVENT_HASH_BITS        7
 
 DECLARE_RWSEM(trace_event_mutex);
 
-static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
+static DEFINE_HASHTABLE(event_hash, EVENT_HASH_BITS);
 
 static int next_event_type = __TRACE_LAST_TYPE + 1;
 
@@ -712,11 +712,8 @@ struct trace_event *ftrace_find_event(int type)
 {
        struct trace_event *event;
        struct hlist_node *n;
-       unsigned key;
 
-       key = type & (EVENT_HASHSIZE - 1);
-
-       hlist_for_each_entry(event, n, &event_hash[key], node) {
+       hash_for_each_possible(event_hash, event, n, node, type) {
                if (event->type == type)
                        return event;
        }
@@ -781,7 +778,6 @@ void trace_event_read_unlock(void)
  */
 int register_ftrace_event(struct trace_event *event)
 {
-       unsigned key;
        int ret = 0;
 
        down_write(&trace_event_mutex);
@@ -833,9 +829,7 @@ int register_ftrace_event(struct trace_event *event)
        if (event->funcs->binary == NULL)
                event->funcs->binary = trace_nop_print;
 
-       key = event->type & (EVENT_HASHSIZE - 1);
-
-       hlist_add_head(&event->node, &event_hash[key]);
+       hash_add(event_hash, &event->node, event->type);
 
        ret = event->type;
  out:
@@ -850,7 +844,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_event);
  */
 int __unregister_ftrace_event(struct trace_event *event)
 {
-       hlist_del(&event->node);
+       hash_del(&event->node);
        list_del(&event->list);
        return 0;
 }
@@ -1323,6 +1317,8 @@ __init static int init_events(void)
                }
        }
 
+       hash_init(event_hash);
+
        return 0;
 }
 early_initcall(init_events);
-- 
1.7.8.6

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