netvsc: use refcount_t for keeping track of sub channels

Rather than a lock and variable, use a refcount_t to keep track
of the number of sub channels.  Don't need to wait for subchannels
on device removal since wait was already done in device_add.

Also fix the error handling; don't wait forever in case of
an error on request to create sub channels.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 907f55960ba8e54440c210c7ade03800cfead497..4747ad48b3cc5278b510306449a2fea7e52115c5 100644 (file)
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -761,8 +761,8 @@ struct netvsc_device {
 
        u32 max_chn;
        u32 num_chn;
-       spinlock_t sc_lock; /* Protects num_sc_offered variable */
-       u32 num_sc_offered;
+
+       refcount_t sc_offered;
 
        /* Holds rndis device info */
        void *extension;

diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index d193d549cec667633817ff21b0d4bb1ca32bc15a..3bd5447277ad6f8868180b23bee51379caf2b242 100644 (file)
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -997,7 +997,6 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
        struct netvsc_device *nvscdev = net_device_to_netvsc_device(ndev);
        u16 chn_index = new_sc->offermsg.offer.sub_channel_index;
        struct netvsc_channel *nvchan;
-       unsigned long flags;
        int ret;
 
        if (chn_index >= nvscdev->num_chn)
@@ -1019,10 +1018,7 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
 
        napi_enable(&nvchan->napi);
 
-       spin_lock_irqsave(&nvscdev->sc_lock, flags);
-       nvscdev->num_sc_offered--;
-       spin_unlock_irqrestore(&nvscdev->sc_lock, flags);
-       if (nvscdev->num_sc_offered == 0)
+       if (refcount_dec_and_test(&nvscdev->sc_offered))
                complete(&nvscdev->channel_init_wait);
 }
 
@@ -1039,12 +1035,9 @@ int rndis_filter_device_add(struct hv_device *dev,
        struct ndis_recv_scale_cap rsscap;
        u32 rsscap_size = sizeof(struct ndis_recv_scale_cap);
        unsigned int gso_max_size = GSO_MAX_SIZE;
-       u32 mtu, size;
-       u32 num_rss_qs;
-       u32 sc_delta;
+       u32 mtu, size, num_rss_qs;
        const struct cpumask *node_cpu_mask;
        u32 num_possible_rss_qs;
-       unsigned long flags;
        int i, ret;
 
        rndis_device = get_rndis_device();
@@ -1067,7 +1060,7 @@ int rndis_filter_device_add(struct hv_device *dev,
        net_device->max_chn = 1;
        net_device->num_chn = 1;
 
-       spin_lock_init(&net_device->sc_lock);
+       refcount_set(&net_device->sc_offered, 0);
 
        net_device->extension = rndis_device;
        rndis_device->ndev = net;
@@ -1204,6 +1197,7 @@ int rndis_filter_device_add(struct hv_device *dev,
        if (num_rss_qs == 0)
                return 0;
 
+       refcount_set(&net_device->sc_offered, num_rss_qs);
        vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);
 
        init_packet = &net_device->channel_init_pkt;
@@ -1219,32 +1213,23 @@ int rndis_filter_device_add(struct hv_device *dev,
                               VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
        if (ret)
                goto out;
-       wait_for_completion(&net_device->channel_init_wait);
 
-       if (init_packet->msg.v5_msg.subchn_comp.status !=
-           NVSP_STAT_SUCCESS) {
+       if (init_packet->msg.v5_msg.subchn_comp.status != NVSP_STAT_SUCCESS) {
                ret = -ENODEV;
                goto out;
        }
+       wait_for_completion(&net_device->channel_init_wait);
+
        net_device->num_chn = 1 +
                init_packet->msg.v5_msg.subchn_comp.num_subchannels;
 
-       ret = rndis_filter_set_rss_param(rndis_device, netvsc_hash_key,
-                                        net_device->num_chn);
-
-       /*
-        * Set the number of sub-channels to be received.
-        */
-       spin_lock_irqsave(&net_device->sc_lock, flags);
-       sc_delta = num_rss_qs - (net_device->num_chn - 1);
-       net_device->num_sc_offered -= sc_delta;
-       spin_unlock_irqrestore(&net_device->sc_lock, flags);
-
+       /* ignore failues from setting rss parameters, still have channels */
+       rndis_filter_set_rss_param(rndis_device, netvsc_hash_key,
+                                  net_device->num_chn);
 out:
        if (ret) {
                net_device->max_chn = 1;
                net_device->num_chn = 1;
-               net_device->num_sc_offered = 0;
        }
 
        return 0; /* return 0 because primary channel can be used alone */
@@ -1259,12 +1244,6 @@ void rndis_filter_device_remove(struct hv_device *dev,
 {
        struct rndis_device *rndis_dev = net_dev->extension;
 
-       /* If not all subchannel offers are complete, wait for them until
-        * completion to avoid race.
-        */
-       if (net_dev->num_sc_offered > 0)
-               wait_for_completion(&net_dev->channel_init_wait);
-
        /* Halt and release the rndis device */
        rndis_filter_halt_device(rndis_dev);