hv_netvsc: Fix the array sizes to be max supported channels

BugLink: http://bugs.launchpad.net/bugs/1583357

The VRSS_CHANNEL_MAX is the max number of channels supported by Hyper-V
hosts. We use it for the related array sizes instead of using NR_CPUS,
which may be set to several thousands.
This patch reduces possible memory allocation failures.
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 9efc2f7d)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/net/hyperv/hyperv_net.h

@@ -619,6 +619,7 @@ struct nvsp_message {
 #define NETVSC_PACKET_SIZE                      4096
 
 #define VRSS_SEND_TAB_SIZE 16
+#define VRSS_CHANNEL_MAX 64
 
 #define RNDIS_MAX_PKT_DEFAULT 8
 #define RNDIS_PKT_ALIGN_DEFAULT 8
@@ -700,13 +701,13 @@ struct netvsc_device {
 
 	struct net_device *ndev;
 
-	struct vmbus_channel *chn_table[NR_CPUS];
+	struct vmbus_channel *chn_table[VRSS_CHANNEL_MAX];
 	u32 send_table[VRSS_SEND_TAB_SIZE];
 	u32 max_chn;
 	u32 num_chn;
 	spinlock_t sc_lock; /* Protects num_sc_offered variable */
 	u32 num_sc_offered;
-	atomic_t queue_sends[NR_CPUS];
+	atomic_t queue_sends[VRSS_CHANNEL_MAX];
 
 	/* Holds rndis device info */
 	void *extension;
@@ -718,7 +719,7 @@ struct netvsc_device {
 	/* The sub channel callback buffer */
 	unsigned char *sub_cb_buf;
 
-	struct multi_send_data msd[NR_CPUS];
+	struct multi_send_data msd[VRSS_CHANNEL_MAX];
 	u32 max_pkt; /* max number of pkt in one send, e.g. 8 */
 	u32 pkt_align; /* alignment bytes, e.g. 8 */
 

drivers/net/hyperv/rndis_filter.c

@@ -1113,9 +1113,9 @@ int rndis_filter_device_add(struct hv_device *dev,
 	if (ret || rsscap.num_recv_que < 2)
 		goto out;
 
-	num_rss_qs = min(device_info->max_num_vrss_chns, rsscap.num_recv_que);
+	net_device->max_chn = min_t(u32, VRSS_CHANNEL_MAX, rsscap.num_recv_que);
 
-	net_device->max_chn = rsscap.num_recv_que;
+	num_rss_qs = min(device_info->max_num_vrss_chns, net_device->max_chn);
 
 	/*
 	 * We will limit the VRSS channels to the number CPUs in the NUMA node