qcacld-3.0: Purge old scan entries if max BSS limit reached

qcacld-2.0 to qcacld-3.0 propagation

In the driver, while processing the scan results, if the max
BSS limit is reached, all the newest scan results are dropped
and stale scan results are updated to upper layers.
To address this, remove the oldest scan entry if the max BSS
limit is reached.

Change-Id: Ib85a8a3b66fbf903311002887a3c5c3d10bfbccf
CRs-Fixed: 991417

core/sme/src/csr/csr_api_scan.c

@@ -2853,6 +2853,53 @@ bool csr_process_bss_desc_for_bkid_list(tpAniSirGlobal pMac,
 
 #endif
 
+/**
+ * csr_purge_old_scan_results() - This function removes old scan entries
+ * @mac_ctx: pointer to Global MAC structure
+ *
+ * This function removes old scan entries
+ *
+ * Return: None
+ */
+
+static void csr_purge_old_scan_results(tpAniSirGlobal mac_ctx)
+{
+	tListElem *pentry, *tmp_entry;
+	tCsrScanResult *presult, *oldest_bss = NULL;
+	uint32_t oldest_entry = 0;
+	uint32_t curr_time = qdf_mc_timer_get_system_ticks();
+
+	csr_ll_unlock(&mac_ctx->scan.scanResultList);
+	pentry = csr_ll_peek_head(&mac_ctx->scan.scanResultList,
+					LL_ACCESS_NOLOCK);
+	while (pentry) {
+		tmp_entry = csr_ll_next(&mac_ctx->scan.scanResultList, pentry,
+			LL_ACCESS_NOLOCK);
+		presult = GET_BASE_ADDR(pentry, tCsrScanResult, Link);
+		if ((curr_time - presult->Result.BssDescriptor.nReceivedTime) >
+		     oldest_entry) {
+			oldest_entry = curr_time -
+				presult->Result.BssDescriptor.nReceivedTime;
+			oldest_bss = presult;
+		}
+		pentry = tmp_entry;
+	}
+	if (oldest_bss) {
+		/* Free the old BSS Entries */
+		if (csr_ll_remove_entry(&mac_ctx->scan.scanResultList,
+		    &oldest_bss->Link, LL_ACCESS_NOLOCK)) {
+			sms_log(mac_ctx, LOG1,
+				FL("Current time delta (%d) of BSSID to be removed" MAC_ADDRESS_STR),
+				(curr_time -
+				oldest_bss->Result.BssDescriptor.nReceivedTime),
+				MAC_ADDR_ARRAY(
+				oldest_bss->Result.BssDescriptor.bssId));
+			csr_free_scan_result_entry(mac_ctx, oldest_bss);
+		}
+	}
+	csr_ll_unlock(&mac_ctx->scan.scanResultList);
+}
+
 static void
 csr_remove_from_tmp_list(tpAniSirGlobal mac_ctx,
 			 uint8_t reason,
@@ -2894,12 +2941,8 @@ csr_remove_from_tmp_list(tpAniSirGlobal mac_ctx,
 		 * LFR candidates came from FW
 		 */
 		if (CSR_SCAN_IS_OVER_BSS_LIMIT(mac_ctx)) {
-			sms_log(mac_ctx, LOGW, FL("BSS limit reached"));
-			if ((bss_dscp->Result.pvIes == NULL) && local_ie)
-				qdf_mem_free(local_ie);
-			csr_free_scan_result_entry(mac_ctx, bss_dscp);
-			/* Continue because there may be duplicated BSS */
-			continue;
+			sms_log(mac_ctx, LOG1, FL("BSS Limit reached"));
+			csr_purge_old_scan_results(mac_ctx);
 		}
 		/* check for duplicate scan results */
 		if (!dup_bss) {
@@ -5896,6 +5939,7 @@ static void csr_scan_result_cfg_aging_timer_handler(void *pv)
 
 	csr_ll_lock(&mac_ctx->scan.scanResultList);
 	entry = csr_ll_peek_head(&mac_ctx->scan.scanResultList, LL_ACCESS_NOLOCK);
+	sms_log(mac_ctx, LOG1, FL(" Ageout time=%d"), ageout_time);
 	while (entry) {
 		tmp_entry = csr_ll_next(&mac_ctx->scan.scanResultList, entry,
 					LL_ACCESS_NOLOCK);

core/sme/src/csr/csr_inside_api.h

@@ -64,7 +64,7 @@
 
 #define CSR_MAX_2_4_GHZ_SUPPORTED_CHANNELS 14
 
-#define CSR_MAX_BSS_SUPPORT            300
+#define CSR_MAX_BSS_SUPPORT            512
 #define SYSTEM_TIME_MSEC_TO_USEC      1000
 
 /* This number minus 1 means the number of times a channel is scanned before a BSS is remvoed from */