Revert "Scan screen: further simplify mutex use (#78)"

This reverts commit c74e52d. The fix was not right, using deferred pthread_cancel (the default). Also the use of locks needs to be revised.
uoaerg · Oct 17, 2020 · 9c21760 · 9c21760
1 parent f247c6a
commit 9c21760
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Showing 3 changed files with 24 additions and 9 deletions.
diff --git a/iw_if.h b/iw_if.h
@@ -251,8 +251,8 @@ struct scan_result {
 	pthread_mutex_t   mutex;
 };
 
-extern void init_scan_list(struct scan_result *sr);
-extern void free_scan_list(struct scan_entry *head);
+extern void scan_result_init(struct scan_result *sr);
+extern void scan_result_fini(struct scan_result *sr);
 extern void *do_scan(void *sr_ptr);
 
 /*

diff --git a/iw_scan.c b/iw_scan.c
@@ -295,7 +295,7 @@ void sort_scan_list(struct scan_entry **headp)
 }
 
 /** De-allocate list. Use after all threads are terminated. */
-void free_scan_list(struct scan_entry *head)
+static void free_scan_list(struct scan_entry *head)
 {
 	if (head) {
 		free_scan_list(head->next);
@@ -304,7 +304,7 @@ void free_scan_list(struct scan_entry *head)
 }
 
 /** Initialize scan results. Requires lock to be taken. */
-void init_scan_list(struct scan_result *sr)
+static void init_scan_list(struct scan_result *sr)
 {
 	free_scan_list(sr->head);
 	free(sr->channel_stats);
@@ -313,7 +313,6 @@ void init_scan_list(struct scan_result *sr)
 	sr->msg[0]        = '\0';
 	sr->max_essid_len = MAX_ESSID_LEN;
 	memset(&(sr->num), 0, sizeof(sr->num));
-	sr->mutex = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
 }
 
 /*
@@ -368,6 +367,24 @@ static void compute_channel_stats(struct scan_result *sr)
 	sr->num.ch_stats = n < MAX_CH_STATS ? n : MAX_CH_STATS;
 }
 
+/*
+ *	Scan results.
+ */
+void scan_result_init(struct scan_result *sr)
+{
+	init_scan_list(sr);
+	pthread_mutex_init(&sr->mutex, NULL);
+}
+
+void scan_result_fini(struct scan_result *sr)
+{
+	pthread_mutex_lock(&sr->mutex);
+	free_scan_list(sr->head);
+	free(sr->channel_stats);
+	pthread_mutex_unlock(&sr->mutex);
+	pthread_mutex_destroy(&sr->mutex);
+}
+
 /** The actual scan thread. */
 void *do_scan(void *sr_ptr)
 {

diff --git a/scan_scr.c b/scan_scr.c
@@ -203,7 +203,7 @@ void scr_aplst_init(void)
 	mvwaddstr(w_aplst, START_LINE, 1, "Waiting for scan data ...");
 	wrefresh(w_aplst);
 
-	init_scan_list(&sr);
+	scan_result_init(&sr);
 	pthread_create(&scan_thread, NULL, do_scan, &sr);
 }
 
@@ -251,8 +251,6 @@ int scr_aplst_loop(WINDOW *w_menu)
 void scr_aplst_fini(void)
 {
 	pthread_cancel(scan_thread);
-	free_scan_list(sr.head);
-	free(sr.channel_stats);
-
+	scan_result_fini(&sr);
 	delwin(w_aplst);
 }