qcacld-3.0: Use request manager for SNR

We are transitioning to the new request manager framework. Change
wlan_hdd_get_snr() and hdd_get_snr_cb() to this framework.

Change-Id: Ib7628ee6931450b3b1ee73a0ede6c21ba6427407
CRs-Fixed: 2005305

core/hdd/inc/wlan_hdd_main.h

@@ -325,7 +325,6 @@ extern spinlock_t hdd_context_lock;
 
 #define STATS_CONTEXT_MAGIC 0x53544154  /* STAT */
 #define POWER_CONTEXT_MAGIC 0x504F5752  /* POWR */
-#define SNR_CONTEXT_MAGIC   0x534E5200  /* SNR */
 #define LINK_CONTEXT_MAGIC  0x4C494E4B  /* LINKSPEED */
 #define LINK_STATUS_MAGIC   0x4C4B5354  /* LINKSTATUS(LNST) */
 #define TEMP_CONTEXT_MAGIC  0x74656d70   /* TEMP (temperature) */

core/hdd/src/wlan_hdd_wext.c

@@ -1768,58 +1768,35 @@ QDF_STATUS wlan_hdd_get_rssi(hdd_adapter_t *pAdapter, int8_t *rssi_value)
 	return QDF_STATUS_SUCCESS;
 }
 
+struct snr_priv {
+	int8_t snr;
+};
+
 /**
  * hdd_get_snr_cb() - "Get SNR" callback function
  * @snr: Current SNR of the station
- * @staId: ID of the station
- * @pContext: opaque context originally passed to SME.  HDD always passes
- *	a &struct statsContext
+ * @sta_id: ID of the station
+ * @context: opaque context originally passed to SME.  HDD always passes
+ *	a cookie for the request context
  *
  * Return: None
  */
-static void hdd_get_snr_cb(int8_t snr, uint32_t staId, void *pContext)
+static void hdd_get_snr_cb(int8_t snr, uint32_t sta_id, void *context)
 {
-	struct statsContext *pStatsContext;
-	hdd_adapter_t *pAdapter;
-
-	if (NULL == pContext) {
-		hdd_err("Bad param");
-		return;
-	}
-
-	pStatsContext = pContext;
-	pAdapter = pStatsContext->pAdapter;
-
-	/* there is a race condition that exists between this callback
-	 * function and the caller since the caller could time out
-	 * either before or while this code is executing.  we use a
-	 * spinlock to serialize these actions
-	 */
-	spin_lock(&hdd_context_lock);
+	struct hdd_request *request;
+	struct snr_priv *priv;
 
-	if ((NULL == pAdapter) || (SNR_CONTEXT_MAGIC != pStatsContext->magic)) {
-		/* the caller presumably timed out so there is nothing
-		 * we can do
-		 */
-		spin_unlock(&hdd_context_lock);
-		hdd_warn("Invalid context, pAdapter [%p] magic [%08x]",
-			 pAdapter, pStatsContext->magic);
+	request = hdd_request_get(context);
+	if (!request) {
+		hdd_err("Obsolete request");
 		return;
 	}
 
-	/* context is valid so caller is still waiting */
-
-	/* paranoia: invalidate the magic */
-	pStatsContext->magic = 0;
-
-	/* copy over the snr */
-	pAdapter->snr = snr;
-
-	/* notify the caller */
-	complete(&pStatsContext->completion);
-
-	/* serialization is complete */
-	spin_unlock(&hdd_context_lock);
+	/* propagate response back to requesting thread */
+	priv = hdd_request_priv(request);
+	priv->snr = snr;
+	hdd_request_complete(request);
+	hdd_request_put(request);
 }
 
 /**
@@ -1831,12 +1808,18 @@ static void hdd_get_snr_cb(int8_t snr, uint32_t staId, void *pContext)
  */
 QDF_STATUS wlan_hdd_get_snr(hdd_adapter_t *pAdapter, int8_t *snr)
 {
-	static struct statsContext context;
 	hdd_context_t *pHddCtx;
 	hdd_station_ctx_t *pHddStaCtx;
 	QDF_STATUS hstatus;
-	unsigned long rc;
 	int valid;
+	int ret;
+	void *cookie;
+	struct hdd_request *request;
+	struct snr_priv *priv;
+	static const struct hdd_request_params params = {
+		.priv_size = sizeof(*priv),
+		.timeout_ms = WLAN_WAIT_TIME_STATS,
+	};
 
 	ENTER();
 
@@ -1853,43 +1836,38 @@ QDF_STATUS wlan_hdd_get_snr(hdd_adapter_t *pAdapter, int8_t *snr)
 
 	pHddStaCtx = WLAN_HDD_GET_STATION_CTX_PTR(pAdapter);
 
-	init_completion(&context.completion);
-	context.pAdapter = pAdapter;
-	context.magic = SNR_CONTEXT_MAGIC;
+	request = hdd_request_alloc(&params);
+	if (!request) {
+		hdd_err("Request allocation failure");
+		return QDF_STATUS_E_FAULT;
+	}
+	cookie = hdd_request_cookie(request);
 
 	hstatus = sme_get_snr(pHddCtx->hHal, hdd_get_snr_cb,
 			      pHddStaCtx->conn_info.staId[0],
-			      pHddStaCtx->conn_info.bssId, &context);
+			      pHddStaCtx->conn_info.bssId, cookie);
 	if (QDF_STATUS_SUCCESS != hstatus) {
 		hdd_err("Unable to retrieve RSSI");
 		/* we'll returned a cached value below */
 	} else {
 		/* request was sent -- wait for the response */
-		rc = wait_for_completion_timeout(&context.completion,
-						 msecs_to_jiffies
-							 (WLAN_WAIT_TIME_STATS));
-		if (!rc) {
+		ret = hdd_request_wait_for_response(request);
+		if (ret) {
 			hdd_err("SME timed out while retrieving SNR");
 			/* we'll now returned a cached value below */
+		} else {
+			/* update the adapter with the fresh results */
+			priv = hdd_request_priv(request);
+			pAdapter->snr = priv->snr;
 		}
 	}
 
-	/* either we never sent a request, we sent a request and
-	 * received a response or we sent a request and timed out.  if
-	 * we never sent a request or if we sent a request and got a
-	 * response, we want to clear the magic out of paranoia.  if
-	 * we timed out there is a race condition such that the
-	 * callback function could be executing at the same time we
-	 * are. of primary concern is if the callback function had
-	 * already verified the "magic" but had not yet set the
-	 * completion variable when a timeout occurred. we serialize
-	 * these activities by invalidating the magic while holding a
-	 * shared spinlock which will cause us to block if the
-	 * callback is currently executing
+	/*
+	 * either we never sent a request, we sent a request and
+	 * received a response or we sent a request and timed out.
+	 * regardless we are done with the request.
 	 */
-	spin_lock(&hdd_context_lock);
-	context.magic = 0;
-	spin_unlock(&hdd_context_lock);
+	hdd_request_put(request);
 
 	*snr = pAdapter->snr;
 	EXIT();