[PATCH] Deplete scan request if new time is less than remaining

[Dmitry Shmidt]

Change-Id: Iea4687f19e4ddeeac391ddcd8c252eade51f4542
Signed-off-by: Dmitry Shmidt <dimitrysh at google.com>
---
 src/utils/eloop.c     | 31 +++++++++++++++++++++++++++++++
 src/utils/eloop.h     | 16 ++++++++++++++++
 wpa_supplicant/scan.c |  6 ++++++
 3 files changed, 53 insertions(+)

diff --git a/src/utils/eloop.c b/src/utils/eloop.c
index ddddcf1..f1c88ee 100644
--- a/src/utils/eloop.c
+++ b/src/utils/eloop.c
@@ -599,6 +599,37 @@ int eloop_is_timeout_registered(eloop_timeout_handler handler,
 }
 
 
+int eloop_deplete_timeout(unsigned int req_secs, unsigned int req_usecs,
+			    eloop_timeout_handler handler, void *eloop_data,
+			    void *user_data)
+{
+	struct os_time now, requested, remaining;
+	struct eloop_timeout *tmp;
+
+	dl_list_for_each(tmp, &eloop.timeout, struct eloop_timeout, list) {
+		if (tmp->handler == handler &&
+		    tmp->eloop_data == eloop_data &&
+		    tmp->user_data == user_data) {
+			requested.sec = req_secs;
+			requested.usec = req_usecs;
+			os_get_time(&now);
+			os_time_sub(&tmp->time, &now, &remaining);
+			if (os_time_before(&requested, &remaining)) {
+				eloop_cancel_timeout(handler, eloop_data,
+						     user_data);
+				eloop_register_timeout(requested.sec,
+						       requested.usec,
+						       handler, eloop_data,
+						       user_data);
+				return 1;
+			}
+		}
+	}
+
+	return 0;
+}
+
+
 int eloop_replenish_timeout(unsigned int req_secs, unsigned int req_usecs,
 			    eloop_timeout_handler handler, void *eloop_data,
 			    void *user_data)
diff --git a/src/utils/eloop.h b/src/utils/eloop.h
index befb070..9c12c05 100644
--- a/src/utils/eloop.h
+++ b/src/utils/eloop.h
@@ -223,6 +223,22 @@ int eloop_is_timeout_registered(eloop_timeout_handler handler,
 				void *eloop_data, void *user_data);
 
 /**
+ * eloop_deplete_timeout - Deplete a timeout that is already registered
+ * @req_secs: Requested number of seconds to the timeout
+ * @req_usecs: Requested number of microseconds to the timeout
+ * @handler: Matching callback function
+ * @eloop_data: Matching eloop_data
+ * @user_data: Matching user_data
+ * Returns: 1 if the timeout is depleted, 0 if no change is made
+ *
+ * Find a registered matching <handler,eloop_data,user_data> timeout. If found,
+ * replenish the timeout if remaining time is less than the requested time.
+ */
+eloop_deplete_timeout(unsigned int req_secs, unsigned int req_usecs,
+			    eloop_timeout_handler handler, void *eloop_data,
+			    void *user_data);
+
+/**
  * eloop_replenish_timeout - Replenish a timeout that is already registered
  * @req_secs: Requested number of seconds to the timeout
  * @req_usecs: Requested number of microseconds to the timeout
diff --git a/wpa_supplicant/scan.c b/wpa_supplicant/scan.c
index 245a8ef..96a01fd 100644
--- a/wpa_supplicant/scan.c
+++ b/wpa_supplicant/scan.c
@@ -913,6 +913,12 @@ void wpa_supplicant_update_scan_int(struct wpa_supplicant *wpa_s, int sec)
  */
 void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec)
 {
+	if (eloop_deplete_timeout(sec, usec, wpa_supplicant_scan, wpa_s, NULL)) {
+		wpa_dbg(wpa_s, MSG_DEBUG, "Rescheduling scan request: %d sec %d "
+			"usec", sec, usec);
+		return;
+	}
+
 	/* If there's at least one network that should be specifically scanned
 	 * then don't cancel the scan and reschedule.  Some drivers do
 	 * background scanning which generates frequent scan results, and that
-- 
1.8.4.1