hyperv: Remove recv_pkt_list and lock

Removed recv_pkt_list and lock, and updated related code, so that
the locking overhead is reduced especially when multiple channels
are in use.

The recv_pkt_list isn't actually necessary because the packets are
processed sequentially in each channel. It has been replaced by a
local variable, and the related lock for this list is also removed.
The is_data_pkt field is not used in receive path, so its assignment
is cleaned up.

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>

4 files changed, 13 insertions, 198 deletions

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 57eb3f906d64..a1af0f7711e2 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -119,27 +119,14 @@ struct ndis_recv_scale_param { /* NDIS_RECEIVE_SCALE_PARAMETERS */
 };
 
 /* Fwd declaration */
-struct hv_netvsc_packet;
 struct ndis_tcp_ip_checksum_info;
 
-/* Represent the xfer page packet which contains 1 or more netvsc packet */
-struct xferpage_packet {
-        struct list_head list_ent;
-        u32 status;
-
-        /* # of netvsc packets this xfer packet contains */
-        u32 count;
-
-        struct vmbus_channel *channel;
-};
-
 /*
  * Represent netvsc packet which contains 1 RNDIS and 1 ethernet frame
  * within the RNDIS
  */
 struct hv_netvsc_packet {
         /* Bookkeeping stuff */
-        struct list_head list_ent;
         u32 status;
 
         struct hv_device *device;
@@ -149,19 +136,8 @@ struct hv_netvsc_packet {
         u16 q_idx;
         struct vmbus_channel *channel;
 
-        /*
-         * Valid only for receives when we break a xfer page packet
-         * into multiple netvsc packets
-         */
-        struct xferpage_packet *xfer_page_pkt;
-
         union {
                 struct {
-                        u64 recv_completion_tid;
-                        void *recv_completion_ctx;
-                        void (*recv_completion)(void *context);
-                } recv;
-                struct {
                         u64 send_completion_tid;
                         void *send_completion_ctx;
                         void (*send_completion)(void *context);
@@ -613,9 +589,6 @@ struct nvsp_message {
 
 #define NETVSC_RECEIVE_BUFFER_ID                0xcafe
 
-/* Preallocated receive packets */
-#define NETVSC_RECEIVE_PACKETLIST_COUNT         256
-
 #define NETVSC_PACKET_SIZE                      2048
 
 #define VRSS_SEND_TAB_SIZE 16
@@ -630,12 +603,6 @@ struct netvsc_device {
         wait_queue_head_t wait_drain;
         bool start_remove;
         bool destroy;
-        /*
-         * List of free preallocated hv_netvsc_packet to represent receive
-         * packet
-         */
-        struct list_head recv_pkt_list;
-        spinlock_t recv_pkt_list_lock;
 
         /* Receive buffer allocated by us but manages by NetVSP */
         void *recv_buf;
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index e7e77f12bc38..b10334773b32 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -387,7 +387,6 @@ static void netvsc_disconnect_vsp(struct netvsc_device *net_device)
 int netvsc_device_remove(struct hv_device *device)
 {
         struct netvsc_device *net_device;
-        struct hv_netvsc_packet *netvsc_packet, *pos;
         unsigned long flags;
 
         net_device = hv_get_drvdata(device);
@@ -416,12 +415,6 @@ int netvsc_device_remove(struct hv_device *device)
         vmbus_close(device->channel);
 
         /* Release all resources */
-        list_for_each_entry_safe(netvsc_packet, pos,
-                                 &net_device->recv_pkt_list, list_ent) {
-                list_del(&netvsc_packet->list_ent);
-                kfree(netvsc_packet);
-        }
-
         if (net_device->sub_cb_buf)
                 vfree(net_device->sub_cb_buf);
 
@@ -641,62 +634,6 @@ retry_send_cmplt:
         }
 }
 
-/* Send a receive completion packet to RNDIS device (ie NetVsp) */
-static void netvsc_receive_completion(void *context)
-{
-        struct hv_netvsc_packet *packet = context;
-        struct hv_device *device = packet->device;
-        struct vmbus_channel *channel;
-        struct netvsc_device *net_device;
-        u64 transaction_id = 0;
-        bool fsend_receive_comp = false;
-        unsigned long flags;
-        struct net_device *ndev;
-        u32 status = NVSP_STAT_NONE;
-
-        /*
-         * Even though it seems logical to do a GetOutboundNetDevice() here to
-         * send out receive completion, we are using GetInboundNetDevice()
-         * since we may have disable outbound traffic already.
-         */
-        net_device = get_inbound_net_device(device);
-        if (!net_device)
-                return;
-        ndev = net_device->ndev;
-
-        /* Overloading use of the lock. */
-        spin_lock_irqsave(&net_device->recv_pkt_list_lock, flags);
-
-        if (packet->status != NVSP_STAT_SUCCESS)
-                packet->xfer_page_pkt->status = NVSP_STAT_FAIL;
-
-        packet->xfer_page_pkt->count--;
-
-        /*
-         * Last one in the line that represent 1 xfer page packet.
-         * Return the xfer page packet itself to the freelist
-         */
-        if (packet->xfer_page_pkt->count == 0) {
-                fsend_receive_comp = true;
-                channel = packet->xfer_page_pkt->channel;
-                transaction_id = packet->completion.recv.recv_completion_tid;
-                status = packet->xfer_page_pkt->status;
-                list_add_tail(&packet->xfer_page_pkt->list_ent,
-                              &net_device->recv_pkt_list);
-
-        }
-
-        /* Put the packet back */
-        list_add_tail(&packet->list_ent, &net_device->recv_pkt_list);
-        spin_unlock_irqrestore(&net_device->recv_pkt_list_lock, flags);
-
-        /* Send a receive completion for the xfer page packet */
-        if (fsend_receive_comp)
-                netvsc_send_recv_completion(device, channel, net_device,
-                                            transaction_id, status);
-
-}
-
 static void netvsc_receive(struct netvsc_device *net_device,
                         struct vmbus_channel *channel,
                         struct hv_device *device,
@@ -704,16 +641,13 @@ static void netvsc_receive(struct netvsc_device *net_device,
 {
         struct vmtransfer_page_packet_header *vmxferpage_packet;
         struct nvsp_message *nvsp_packet;
-        struct hv_netvsc_packet *netvsc_packet = NULL;
-        /* struct netvsc_driver *netvscDriver; */
-        struct xferpage_packet *xferpage_packet = NULL;
+        struct hv_netvsc_packet nv_pkt;
+        struct hv_netvsc_packet *netvsc_packet = &nv_pkt;
+        u32 status = NVSP_STAT_SUCCESS;
         int i;
         int count = 0;
-        unsigned long flags;
         struct net_device *ndev;
 
-        LIST_HEAD(listHead);
-
         ndev = net_device->ndev;
 
         /*
@@ -746,78 +680,14 @@ static void netvsc_receive(struct netvsc_device *net_device,
                 return;
         }
 
-        /*
-         * Grab free packets (range count + 1) to represent this xfer
-         * page packet. +1 to represent the xfer page packet itself.
-         * We grab it here so that we know exactly how many we can
-         * fulfil
-         */
-        spin_lock_irqsave(&net_device->recv_pkt_list_lock, flags);
-        while (!list_empty(&net_device->recv_pkt_list)) {
-                list_move_tail(net_device->recv_pkt_list.next, &listHead);
-                if (++count == vmxferpage_packet->range_cnt + 1)
-                        break;
-        }
-        spin_unlock_irqrestore(&net_device->recv_pkt_list_lock, flags);
-
-        /*
-         * We need at least 2 netvsc pkts (1 to represent the xfer
-         * page and at least 1 for the range) i.e. we can handled
-         * some of the xfer page packet ranges...
-         */
-        if (count < 2) {
-                netdev_err(ndev, "Got only %d netvsc pkt...needed "
-                        "%d pkts. Dropping this xfer page packet completely!\n",
-                        count, vmxferpage_packet->range_cnt + 1);
-
-                /* Return it to the freelist */
-                spin_lock_irqsave(&net_device->recv_pkt_list_lock, flags);
-                for (i = count; i != 0; i--) {
-                        list_move_tail(listHead.next,
-                                       &net_device->recv_pkt_list);
-                }
-                spin_unlock_irqrestore(&net_device->recv_pkt_list_lock,
-                                       flags);
-
-                netvsc_send_recv_completion(device, channel, net_device,
-                                            vmxferpage_packet->d.trans_id,
-                                            NVSP_STAT_FAIL);
-
-                return;
-        }
-
-        /* Remove the 1st packet to represent the xfer page packet itself */
-        xferpage_packet = (struct xferpage_packet *)listHead.next;
-        list_del(&xferpage_packet->list_ent);
-        xferpage_packet->status = NVSP_STAT_SUCCESS;
-        xferpage_packet->channel = channel;
-
-        /* This is how much we can satisfy */
-        xferpage_packet->count = count - 1;
-
-        if (xferpage_packet->count != vmxferpage_packet->range_cnt) {
-                netdev_err(ndev, "Needed %d netvsc pkts to satisfy "
-                        "this xfer page...got %d\n",
-                        vmxferpage_packet->range_cnt, xferpage_packet->count);
-        }
+        count = vmxferpage_packet->range_cnt;
+        netvsc_packet->device = device;
+        netvsc_packet->channel = channel;
 
         /* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
-        for (i = 0; i < (count - 1); i++) {
-                netvsc_packet = (struct hv_netvsc_packet *)listHead.next;
-                list_del(&netvsc_packet->list_ent);
-
+        for (i = 0; i < count; i++) {
                 /* Initialize the netvsc packet */
                 netvsc_packet->status = NVSP_STAT_SUCCESS;
-                netvsc_packet->xfer_page_pkt = xferpage_packet;
-                netvsc_packet->completion.recv.recv_completion =
-                                        netvsc_receive_completion;
-                netvsc_packet->completion.recv.recv_completion_ctx =
-                                        netvsc_packet;
-                netvsc_packet->device = device;
-                /* Save this so that we can send it back */
-                netvsc_packet->completion.recv.recv_completion_tid =
-                                        vmxferpage_packet->d.trans_id;
-
                 netvsc_packet->data = (void *)((unsigned long)net_device->
                         recv_buf + vmxferpage_packet->ranges[i].byte_offset);
                 netvsc_packet->total_data_buflen =
@@ -826,10 +696,12 @@ static void netvsc_receive(struct netvsc_device *net_device,
                 /* Pass it to the upper layer */
                 rndis_filter_receive(device, netvsc_packet);
 
-                netvsc_receive_completion(netvsc_packet->
-                                completion.recv.recv_completion_ctx);
+                if (netvsc_packet->status != NVSP_STAT_SUCCESS)
+                        status = NVSP_STAT_FAIL;
         }
 
+        netvsc_send_recv_completion(device, channel, net_device,
+                                    vmxferpage_packet->d.trans_id, status);
 }
 
 
@@ -956,11 +828,9 @@ void netvsc_channel_cb(void *context)
 int netvsc_device_add(struct hv_device *device, void *additional_info)
 {
         int ret = 0;
-        int i;
         int ring_size =
         ((struct netvsc_device_info *)additional_info)->ring_size;
         struct netvsc_device *net_device;
-        struct hv_netvsc_packet *packet, *pos;
         struct net_device *ndev;
 
         net_device = alloc_net_device(device);
@@ -981,18 +851,6 @@ int netvsc_device_add(struct hv_device *device, void *additional_info)
         ndev = net_device->ndev;
 
         /* Initialize the NetVSC channel extension */
-        spin_lock_init(&net_device->recv_pkt_list_lock);
-
-        INIT_LIST_HEAD(&net_device->recv_pkt_list);
-
-        for (i = 0; i < NETVSC_RECEIVE_PACKETLIST_COUNT; i++) {
-                packet = kzalloc(sizeof(struct hv_netvsc_packet), GFP_KERNEL);
-                if (!packet)
-                        break;
-
-                list_add_tail(&packet->list_ent,
-                              &net_device->recv_pkt_list);
-        }
         init_completion(&net_device->channel_init_wait);
 
         set_per_channel_state(device->channel, net_device->cb_buffer);
@@ -1028,16 +886,8 @@ close:
 
 cleanup:
 
-        if (net_device) {
-                list_for_each_entry_safe(packet, pos,
-                                         &net_device->recv_pkt_list,
-                                         list_ent) {
-                        list_del(&packet->list_ent);
-                        kfree(packet);
-                }
-
+        if (net_device)
                 kfree(net_device);
-        }
 
         return ret;
 }
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 093cf3fc46b8..8f6d53a2ed95 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -638,7 +638,7 @@ int netvsc_recv_callback(struct hv_device *device_obj,
                 __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
                                        packet->vlan_tci);
 
-        skb_record_rx_queue(skb, packet->xfer_page_pkt->channel->
+        skb_record_rx_queue(skb, packet->channel->
                             offermsg.offer.sub_channel_index %
                             net->real_num_rx_queues);
 
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index d92cfbe43410..48f5a0fbd674 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -401,8 +401,6 @@ static void rndis_filter_receive_data(struct rndis_device *dev,
         pkt->total_data_buflen = rndis_pkt->data_len;
         pkt->data = (void *)((unsigned long)pkt->data + data_offset);
 
-        pkt->is_data_pkt = true;
-
         vlan = rndis_get_ppi(rndis_pkt, IEEE_8021Q_INFO);
         if (vlan) {
                 pkt->vlan_tci = VLAN_TAG_PRESENT | vlan->vlanid |