[PATCH 3/4] Drivers: hv: kvp: Fix two "this statement may fall through" warnings

[PATCH 3/4] Drivers: hv: kvp: Fix two "this statement may fall through" warnings

[kys]

From: Dexuan Cui <decui@microsoft.com>

We don't need to call process_ib_ipinfo() if message->kvp_hdr.operation is
KVP_OP_GET_IP_INFO in kvp_send_key(), because here we just need to pass on
the op code from the host to the userspace; when the userspace returns
the info requested by the host, we pass the info on to the host in
kvp_respond_to_host() -> process_ob_ipinfo(). BTW, the current buggy code
actually doesn't cause any harm, because only message->kvp_hdr.operation
is used by the userspace, in the case of KVP_OP_GET_IP_INFO.

The patch also adds a missing "break;" in kvp_send_key(). BTW, the current
buggy code actually doesn't cause any harm, because in the case of
KVP_OP_SET, the unexpected fall-through corrupts
message->body.kvp_set.data.key_size, but that is not really used: see
the definition of struct hv_kvp_exchg_msg_value.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/hv_kvp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 023bd185d21a..a7513a8a8e37 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -353,7 +353,6 @@ static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
 
 		out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
 
-	default:
 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
 				MAX_ADAPTER_ID_SIZE,
 				UTF16_LITTLE_ENDIAN,
@@ -406,7 +405,7 @@ kvp_send_key(struct work_struct *dummy)
 		process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
 		break;
 	case KVP_OP_GET_IP_INFO:
-		process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
+		/* We only need to pass on message->kvp_hdr.operation.  */
 		break;
 	case KVP_OP_SET:
 		switch (in_msg->body.kvp_set.data.value_type) {
@@ -446,6 +445,9 @@ kvp_send_key(struct work_struct *dummy)
 			break;
 
 		}
+
+		break;
+
 	case KVP_OP_GET:
 		message->body.kvp_set.data.key_size =
 			utf16s_to_utf8s(
-- 
2.18.0

[PATCH 4/4] Drivers: hv: vmbus: Use cpumask_var_t for on-stack cpu mask

[kys]

From: Dexuan Cui <decui@microsoft.com>

A cpumask structure on the stack can cause a warning with
CONFIG_NR_CPUS=8192 (e.g. Ubuntu 16.04 and 18.04 use this):

drivers/hv//channel_mgmt.c: In function ‘init_vp_index’:
drivers/hv//channel_mgmt.c:702:1: warning: the frame size of 1032 bytes
  is larger than 1024 bytes [-Wframe-larger-than=]

Nowadays it looks most distros enable CONFIG_CPUMASK_OFFSTACK=y, and
hence we can work around the warning by using cpumask_var_t.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/channel_mgmt.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index e7598b569bea..d943fa022e34 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -601,16 +601,18 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 	bool perf_chn = vmbus_devs[dev_type].perf_device;
 	struct vmbus_channel *primary = channel->primary_channel;
 	int next_node;
-	struct cpumask available_mask;
+	cpumask_var_t available_mask;
 	struct cpumask *alloced_mask;
 
 	if ((vmbus_proto_version == VERSION_WS2008) ||
-	    (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
+	    (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) ||
+	    !alloc_cpumask_var(&available_mask, GFP_KERNEL)) {
 		/*
 		 * Prior to win8, all channel interrupts are
 		 * delivered on cpu 0.
 		 * Also if the channel is not a performance critical
 		 * channel, bind it to cpu 0.
+		 * In case alloc_cpumask_var() fails, bind it to cpu 0.
 		 */
 		channel->numa_node = 0;
 		channel->target_cpu = 0;
@@ -648,7 +650,7 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 		cpumask_clear(alloced_mask);
 	}
 
-	cpumask_xor(&available_mask, alloced_mask,
+	cpumask_xor(available_mask, alloced_mask,
 		    cpumask_of_node(primary->numa_node));
 
 	cur_cpu = -1;
@@ -666,10 +668,10 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 	}
 
 	while (true) {
-		cur_cpu = cpumask_next(cur_cpu, &available_mask);
+		cur_cpu = cpumask_next(cur_cpu, available_mask);
 		if (cur_cpu >= nr_cpu_ids) {
 			cur_cpu = -1;
-			cpumask_copy(&available_mask,
+			cpumask_copy(available_mask,
 				     cpumask_of_node(primary->numa_node));
 			continue;
 		}
@@ -699,6 +701,8 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 
 	channel->target_cpu = cur_cpu;
 	channel->target_vp = hv_cpu_number_to_vp_number(cur_cpu);
+
+	free_cpumask_var(available_mask);
 }
 
 static void vmbus_wait_for_unload(void)
-- 
2.18.0