qcacmn: Use atomic allocation for all scheduler context scan allocations

In low memory environments using GFP_KERNEL flag may cause
scheduler thread to sleep. Scheduler thread callback handlers
are expected to be atomic in nature to ensure timely execution
of different commands. Move all allocations done by scan module
in scheduler thread context to atomic allocation.

Change-Id: Iee3eafbc00a3afea0687ba67b3041ec0816094cc
CRs-Fixed: 2232553

os_if/linux/scan/src/wlan_cfg80211_scan.c

@@ -831,7 +831,7 @@ static void wlan_vendor_scan_callback(struct cfg80211_scan_request *req,
 	skb = cfg80211_vendor_event_alloc(req->wdev->wiphy, req->wdev,
 			SCAN_DONE_EVENT_BUF_SIZE + 4 + NLMSG_HDRLEN,
 			QCA_NL80211_VENDOR_SUBCMD_SCAN_DONE_INDEX,
-			GFP_KERNEL);
+			GFP_ATOMIC);
 
 	if (!skb) {
 		cfg80211_err("skb alloc failed");
@@ -877,7 +877,7 @@ static void wlan_vendor_scan_callback(struct cfg80211_scan_request *req,
 	if (nla_put_u8(skb, QCA_WLAN_VENDOR_ATTR_SCAN_STATUS, scan_status))
 		goto nla_put_failure;
 
-	cfg80211_vendor_event(skb, GFP_KERNEL);
+	cfg80211_vendor_event(skb, GFP_ATOMIC);
 	qdf_mem_free(req);
 
 	return;
@@ -1737,7 +1737,7 @@ wlan_cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
 	data.boottime_ns = bss->boottime_ns;
 	data.signal = bss->rssi;
 	return cfg80211_inform_bss_frame_data(wiphy, &data, bss->mgmt,
-					      bss->frame_len, GFP_KERNEL);
+					      bss->frame_len, GFP_ATOMIC);
 }
 #else
 struct cfg80211_bss *
@@ -1747,7 +1747,7 @@ wlan_cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
 {
 	return cfg80211_inform_bss_frame(wiphy, bss->chan, bss->mgmt,
 					 bss->frame_len,
-					 bss->rssi, GFP_KERNEL);
+					 bss->rssi, GFP_ATOMIC);
 }
 #endif
 
@@ -1781,7 +1781,7 @@ void wlan_cfg80211_inform_bss_frame(struct wlan_objmgr_pdev *pdev,
 	wiphy = pdev_ospriv->wiphy;
 
 	bss_data.frame_len = wlan_get_frame_len(scan_params);
-	bss_data.mgmt = qdf_mem_malloc(bss_data.frame_len);
+	bss_data.mgmt = qdf_mem_malloc_atomic(bss_data.frame_len);
 	if (!bss_data.mgmt) {
 		cfg80211_err("mem alloc failed");
 		return;