msm: ipa3: add lock for num_q6_rule

There is a race condition be observed
on global variable num_q6_rule used in
ipa wan-driver. The fix is to add lock
to prevent different threads are accessing
it at the same time.

Bug: 68992477
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>

drivers/platform/msm/ipa/ipa_v2/rmnet_ipa.c

@@ -398,12 +398,15 @@ int copy_ul_filter_rule_to_ipa(struct ipa_install_fltr_rule_req_msg_v01
 {
 	int i, j;
 
+	/* prevent multi-threads accessing num_q6_rule */
+	mutex_lock(&add_mux_channel_lock);
 	if (rule_req->filter_spec_list_valid == true) {
 		num_q6_rule = rule_req->filter_spec_list_len;
 		IPAWANDBG("Received (%d) install_flt_req\n", num_q6_rule);
 	} else {
 		num_q6_rule = 0;
 		IPAWANERR("got no UL rules from modem\n");
+		mutex_unlock(&add_mux_channel_lock);
 		return -EINVAL;
 	}
 
@@ -597,9 +600,11 @@ failure:
 	num_q6_rule = 0;
 	memset(ipa_qmi_ctx->q6_ul_filter_rule, 0,
 		sizeof(ipa_qmi_ctx->q6_ul_filter_rule));
+	mutex_unlock(&add_mux_channel_lock);
 	return -EINVAL;
 
 success:
+	mutex_unlock(&add_mux_channel_lock);
 	return 0;
 }
 
@@ -1499,9 +1504,12 @@ static int ipa_wwan_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 				/* already got Q6 UL filter rules*/
 				if (ipa_qmi_ctx &&
 					ipa_qmi_ctx->modem_cfg_emb_pipe_flt
-					== false)
+					== false) {
+					/* protect num_q6_rule */
+					mutex_lock(&add_mux_channel_lock);
 					rc = wwan_add_ul_flt_rule_to_ipa();
-				else
+					mutex_unlock(&add_mux_channel_lock);
+				} else
 					rc = 0;
 				egress_set = true;
 				if (rc)

drivers/platform/msm/ipa/ipa_v3/rmnet_ipa.c

@@ -412,6 +412,8 @@ int ipa3_copy_ul_filter_rule_to_ipa(struct ipa_install_fltr_rule_req_msg_v01
 {
 	int i, j;
 
+	/* prevent multi-threads accessing rmnet_ipa3_ctx->num_q6_rules */
+	mutex_lock(&rmnet_ipa3_ctx->add_mux_channel_lock);
 	if (rule_req->filter_spec_ex_list_valid == true) {
 		rmnet_ipa3_ctx->num_q6_rules =
 			rule_req->filter_spec_ex_list_len;
@@ -420,6 +422,8 @@ int ipa3_copy_ul_filter_rule_to_ipa(struct ipa_install_fltr_rule_req_msg_v01
 	} else {
 		rmnet_ipa3_ctx->num_q6_rules = 0;
 		IPAWANERR("got no UL rules from modem\n");
+		mutex_unlock(&rmnet_ipa3_ctx->
+					add_mux_channel_lock);
 		return -EINVAL;
 	}
 
@@ -622,9 +626,13 @@ failure:
 	rmnet_ipa3_ctx->num_q6_rules = 0;
 	memset(ipa3_qmi_ctx->q6_ul_filter_rule, 0,
 		sizeof(ipa3_qmi_ctx->q6_ul_filter_rule));
+	mutex_unlock(&rmnet_ipa3_ctx->
+		add_mux_channel_lock);
 	return -EINVAL;
 
 success:
+	mutex_unlock(&rmnet_ipa3_ctx->
+		add_mux_channel_lock);
 	return 0;
 }