Cleanup: extract function to borrow hashlist bucket

This is going to reused by the event notifier system.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I5132273ae79a84afdfbf0f88c8042c2b3828d782

diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c
index 02e6704e4f2fd8464841a6c20567149bf1a6701b..d9efebe6bae215427d304335b6c564fb6939168b 100644 (file)
--- a/liblttng-ust/lttng-events.c
+++ b/liblttng-ust/lttng-events.c
@@ -560,6 +560,23 @@ end:
        return ret;
 }
 
+static inline
+struct cds_hlist_head *borrow_hash_table_bucket(
+               struct cds_hlist_head *hash_table,
+               unsigned int hash_table_size,
+               const struct lttng_event_desc *desc)
+{
+       const char *event_name;
+       size_t name_len;
+       uint32_t hash;
+
+       event_name = desc->name;
+       name_len = strlen(event_name);
+
+       hash = jhash(event_name, name_len, 0);
+       return &hash_table[hash & (hash_table_size - 1)];
+}
+
 /*
  * Supports event creation while tracing session is active.
  */
@@ -567,18 +584,15 @@ static
 int lttng_event_create(const struct lttng_event_desc *desc,
                struct lttng_channel *chan)
 {
-       const char *event_name = desc->name;
        struct lttng_event *event;
        struct lttng_session *session = chan->session;
        struct cds_hlist_head *head;
        int ret = 0;
-       size_t name_len = strlen(event_name);
-       uint32_t hash;
        int notify_socket, loglevel;
        const char *uri;
 
-       hash = jhash(event_name, name_len, 0);
-       head = &chan->session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+       head = borrow_hash_table_bucket(chan->session->events_ht.table,
+               LTTNG_UST_EVENT_HT_SIZE, desc);
 
        notify_socket = lttng_get_notify_socket(session->owner);
        if (notify_socket < 0) {
@@ -624,7 +638,7 @@ int lttng_event_create(const struct lttng_event_desc *desc,
                session,
                session->objd,
                chan->objd,
-               event_name,
+               desc->name,
                loglevel,
                desc->signature,
                desc->nr_fields,
@@ -785,22 +799,16 @@ void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
                        bool found = false;
                        struct cds_hlist_head *head;
                        struct cds_hlist_node *node;
-                       const char *event_name;
-                       size_t name_len;
-                       uint32_t hash;
 
                        desc = probe_desc->event_desc[i];
                        if (!lttng_desc_match_enabler(desc,
                                        lttng_event_enabler_as_enabler(event_enabler)))
                                continue;
-                       event_name = desc->name;
-                       name_len = strlen(event_name);
 
-                       /*
-                        * Check if already created.
-                        */
-                       hash = jhash(event_name, name_len, 0);
-                       head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+                       head = borrow_hash_table_bucket(
+                               session->events_ht.table,
+                               LTTNG_UST_EVENT_HT_SIZE, desc);
+
                        cds_hlist_for_each_entry(event, node, head, hlist) {
                                if (event->desc == desc
                                                && event->chan == event_enabler->chan) {
@@ -848,14 +856,8 @@ void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_de
         */
        for (i = 0; i < provider_desc->nr_events; i++) {
                const struct lttng_event_desc *event_desc;
-               const char *event_name;
-               size_t name_len;
-               uint32_t hash;
 
                event_desc = provider_desc->event_desc[i];
-               event_name = event_desc->name;
-               name_len = strlen(event_name);
-               hash = jhash(event_name, name_len, 0);
 
                /* Iterate over all session to find the current event description. */
                cds_list_for_each_entry(session, sessionsp, node) {
@@ -863,7 +865,10 @@ void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_de
                         * Get the list of events in the hashtable bucket and iterate to
                         * find the event matching this descriptor.
                         */
-                       head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+                       head = borrow_hash_table_bucket(
+                               session->events_ht.table,
+                               LTTNG_UST_EVENT_HT_SIZE, event_desc);
+
                        cds_hlist_for_each_entry(event, node, head, hlist) {
                                if (event_desc == event->desc) {
                                        /* Queue the unregistration of this event. */
@@ -885,14 +890,8 @@ void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_de
         */
        for (i = 0; i < provider_desc->nr_events; i++) {
                const struct lttng_event_desc *event_desc;
-               const char *event_name;
-               size_t name_len;
-               uint32_t hash;
 
                event_desc = provider_desc->event_desc[i];
-               event_name = event_desc->name;
-               name_len = strlen(event_name);
-               hash = jhash(event_name, name_len, 0);
 
                /* Iterate over all sessions to find the current event description. */
                cds_list_for_each_entry(session, sessionsp, node) {
@@ -900,7 +899,10 @@ void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_de
                         * Get the list of events in the hashtable bucket and iterate to
                         * find the event matching this descriptor.
                         */
-                       head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
+                       head = borrow_hash_table_bucket(
+                               session->events_ht.table,
+                               LTTNG_UST_EVENT_HT_SIZE, event_desc);
+
                        cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
                                if (event_desc == event->desc) {
                                        /* Destroy enums of the current event. */