[PATCH v3 06/17] tracepoint: use new hashtable implementation

[Sasha Levin]

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

Signed-off-by: Sasha Levin <levinsasha...@gmail.com>
---
 kernel/tracepoint.c |   27 +++++++++++----------------
 1 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index d96ba22..854df92 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -26,6 +26,7 @@
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/static_key.h>
+#include <linux/hashtable.h>
 
 extern struct tracepoint * const __start___tracepoints_ptrs[];
 extern struct tracepoint * const __stop___tracepoints_ptrs[];
@@ -49,8 +50,7 @@ static LIST_HEAD(tracepoint_module_list);
  * Protected by tracepoints_mutex.
  */
 #define TRACEPOINT_HASH_BITS 6
-#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
-static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
+static DEFINE_HASHTABLE(tracepoint_table, TRACEPOINT_HASH_BITS);
 
 /*
  * Note about RCU :
@@ -191,16 +191,15 @@ tracepoint_entry_remove_probe(struct tracepoint_entry 
*entry,
  */
 static struct tracepoint_entry *get_tracepoint(const char *name)
 {
-       struct hlist_head *head;
        struct hlist_node *node;
        struct tracepoint_entry *e;
        u32 hash = jhash(name, strlen(name), 0);
 
-       head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
-       hlist_for_each_entry(e, node, head, hlist) {
+       hash_for_each_possible(tracepoint_table, e, node, hlist, hash) {
                if (!strcmp(name, e->name))
                        return e;
        }
+
        return NULL;
 }
 
@@ -210,19 +209,13 @@ static struct tracepoint_entry *get_tracepoint(const char 
*name)
  */
 static struct tracepoint_entry *add_tracepoint(const char *name)
 {
-       struct hlist_head *head;
-       struct hlist_node *node;
        struct tracepoint_entry *e;
        size_t name_len = strlen(name) + 1;
        u32 hash = jhash(name, name_len-1, 0);
 
-       head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
-       hlist_for_each_entry(e, node, head, hlist) {
-               if (!strcmp(name, e->name)) {
-                       printk(KERN_NOTICE
-                               "tracepoint %s busy\n", name);
-                       return ERR_PTR(-EEXIST);        /* Already there */
-               }
+       if (get_tracepoint(name)) {
+               printk(KERN_NOTICE "tracepoint %s busy\n", name);
+               return ERR_PTR(-EEXIST);        /* Already there */
        }
        /*
         * Using kmalloc here to allocate a variable length element. Could
@@ -234,7 +227,7 @@ static struct tracepoint_entry *add_tracepoint(const char 
*name)
        memcpy(&e->name[0], name, name_len);
        e->funcs = NULL;
        e->refcount = 0;
-       hlist_add_head(&e->hlist, head);
+       hash_add(tracepoint_table, &e->hlist, hash);
        return e;
 }
 
@@ -244,7 +237,7 @@ static struct tracepoint_entry *add_tracepoint(const char 
*name)
  */
 static inline void remove_tracepoint(struct tracepoint_entry *e)
 {
-       hlist_del(&e->hlist);
+       hash_del(&e->hlist);
        kfree(e);
 }
 
@@ -722,6 +715,8 @@ struct notifier_block tracepoint_module_nb = {
 
 static int init_tracepoints(void)
 {
+       hash_init(tracepoint_table);
+
        return register_module_notifier(&tracepoint_module_nb);
 }
 __initcall(init_tracepoints);
-- 
1.7.8.6

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