[PATCH net-next,v2,1/2] hyperv: Remove recv_pkt_list and lock

From: Haiyang Zhang
Date: Mon Apr 21 2014 - 16:59:58 EST

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 It has been replaced by a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@xxxxxxxxxxxxx>
Reviewed-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/net/hyperv/hyperv_net.h | 33 -------
drivers/net/hyperv/netvsc.c | 174 +++----------------------------------
drivers/net/hyperv/netvsc_drv.c | 2 +-
drivers/net/hyperv/rndis_filter.c | 2 -
4 files changed, 13 insertions(+), 198 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 57eb3f9..a1af0f7 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 e7e77f1..b103347 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 093cf3f..8f6d53a 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 d92cfbe..48f5a0f 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 |
--
1.7.4.1

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