qcacld-2.0: Purge old scan entries if max BSS limit reached

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

2 files changed, 55 insertions, 12 deletions

diff --git a/CORE/SME/src/csr/csrApiScan.c b/CORE/SME/src/csr/csrApiScan.c
index c6847d919546..d6d97eb79502 100644
--- a/CORE/SME/src/csr/csrApiScan.c
+++ b/CORE/SME/src/csr/csrApiScan.c
@@ -111,6 +111,7 @@ eHalStatus csrSetBGScanChannelList( tpAniSirGlobal pMac, tANI_U8 *pAdjustChannel
 void csrReleaseCmdSingle(tpAniSirGlobal pMac, tSmeCmd *pCommand);
 tANI_BOOLEAN csrRoamIsValidChannel( tpAniSirGlobal pMac, tANI_U8 channel );
 void csrPruneChannelListForMode( tpAniSirGlobal pMac, tCsrChannel *pChannelList );
+void csr_purge_old_scan_results(tpAniSirGlobal mac_ctx);
 
 #define CSR_IS_SOCIAL_CHANNEL(channel) (((channel) == 1) || ((channel) == 6) || ((channel) == 11) )
 
@@ -3285,16 +3286,8 @@ static void csrMoveTempScanResultsToMainList(tpAniSirGlobal pMac,
 #endif
           )
         {
-            //Limit reach
-            smsLog(pMac, LOGW, FL("  BSS limit reached"));
-            //Free the resources
-            if( (pBssDescription->Result.pvIes == NULL) && pIesLocal )
-            {
-                vos_mem_free(pIesLocal);
-            }
-            csrFreeScanResultEntry(pMac, pBssDescription);
-            //Continue because there may be duplicated BSS
-            continue;
+            smsLog(pMac, LOG1, FL("########## BSS Limit reached ###########"));
+            csr_purge_old_scan_results(pMac);
         }
         // check for duplicate scan results
         if ( !fDupBss )
@@ -3401,6 +3394,53 @@ end:
     return;
 }
 
+/**
+ * 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
+ */
+
+void csr_purge_old_scan_results(tpAniSirGlobal mac_ctx)
+{
+	tListElem *pentry, *tmp_entry;
+	tCsrScanResult *presult, *oldest_bss = NULL;
+	tANI_TIMESTAMP oldest_entry = 0;
+	tANI_TIMESTAMP curr_time =
+		(tANI_TIMESTAMP)palGetTickCount(mac_ctx->hHdd);
+
+	csrLLLock(&mac_ctx->scan.scanResultList);
+	pentry = csrLLPeekHead(&mac_ctx->scan.scanResultList, LL_ACCESS_NOLOCK);
+	while(pentry)
+	{
+		tmp_entry = csrLLNext(&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(csrLLRemoveEntry(&mac_ctx->scan.scanResultList,
+		   &oldest_bss->Link, LL_ACCESS_NOLOCK)) {
+			smsLog(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));
+			csrFreeScanResultEntry(mac_ctx, oldest_bss);
+		}
+	}
+	csrLLUnlock(&mac_ctx->scan.scanResultList);
+}
 
 static tCsrScanResult *
 csrScanSaveBssDescription(tpAniSirGlobal pMac,
@@ -6823,14 +6863,17 @@ static void csrScanResultCfgAgingTimerHandler(void *pv)
 
     csrLLLock(&pMac->scan.scanResultList);
     pEntry = csrLLPeekHead( &pMac->scan.scanResultList, LL_ACCESS_NOLOCK );
+    smsLog(pMac, LOG1, FL(" Ageout time=%d"),ageOutTime);
     while( pEntry )
     {
         tmpEntry = csrLLNext(&pMac->scan.scanResultList, pEntry,
                                       LL_ACCESS_NOLOCK);
         pResult = GET_BASE_ADDR( pEntry, tCsrScanResult, Link );
+
         if((curTime - pResult->Result.BssDescriptor.nReceivedTime) > ageOutTime)
         {
-            smsLog(pMac, LOGW, " age out due to time out");
+            smsLog(pMac, LOG1, FL("age out due to time out for BSSID" MAC_ADDRESS_STR),
+                           MAC_ADDR_ARRAY(pResult->Result.BssDescriptor.bssId));
             csrScanAgeOutBss(pMac, pResult);
         }
         pEntry = tmpEntry;
diff --git a/CORE/SME/src/csr/csrInsideApi.h b/CORE/SME/src/csr/csrInsideApi.h
index 9cf60d4a105c..f42fca4f31a9 100644
--- a/CORE/SME/src/csr/csrInsideApi.h
+++ b/CORE/SME/src/csr/csrInsideApi.h
@@ -71,7 +71,7 @@
 
 #define CSR_MAX_2_4_GHZ_SUPPORTED_CHANNELS 14
 
-#define CSR_MAX_BSS_SUPPORT            250
+#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