On Thu, Jun 06, 2013 at 05:54:38PM +0800, Jason Wang wrote: > Linear search were used in both get_slot() and macvtap_get_queue(), this is > because: > > - macvtap didn't reshuffle the array of taps when create or destroy a queue, > so > when adding a new queue, macvtap must do linear search to find a location > for > the new queue. This will also complicate the TUNSETQUEUE implementation for > multiqueue API. > - the queue itself didn't track the queue index, so the we must do a linear > search in the array to find the location of a existed queue. > > The solution is straightforward: reshuffle the array and introduce a > queue_index > to macvtap_queue. > > Signed-off-by: Jason Wang <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]> > --- > drivers/net/macvtap.c | 64 +++++++++++++++--------------------------------- > 1 files changed, 20 insertions(+), 44 deletions(-) > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > index d18130b..5ccba99 100644 > --- a/drivers/net/macvtap.c > +++ b/drivers/net/macvtap.c > @@ -44,6 +44,7 @@ struct macvtap_queue { > struct macvlan_dev __rcu *vlan; > struct file *file; > unsigned int flags; > + u16 queue_index; > }; > > static struct proto macvtap_proto = { > @@ -84,30 +85,10 @@ static const struct proto_ops macvtap_socket_ops; > */ > static DEFINE_SPINLOCK(macvtap_lock); > > -/* > - * get_slot: return a [unused/occupied] slot in vlan->taps[]: > - * - if 'q' is NULL, return the first empty slot; > - * - otherwise, return the slot this pointer occupies. > - */ > -static int get_slot(struct macvlan_dev *vlan, struct macvtap_queue *q) > -{ > - int i; > - > - for (i = 0; i < MAX_MACVTAP_QUEUES; i++) { > - if (rcu_dereference_protected(vlan->taps[i], > - lockdep_is_held(&macvtap_lock)) > == q) > - return i; > - } > - > - /* Should never happen */ > - BUG_ON(1); > -} > - > static int macvtap_set_queue(struct net_device *dev, struct file *file, > struct macvtap_queue *q) > { > struct macvlan_dev *vlan = netdev_priv(dev); > - int index; > int err = -EBUSY; > > spin_lock(&macvtap_lock); > @@ -115,12 +96,12 @@ static int macvtap_set_queue(struct net_device *dev, > struct file *file, > goto out; > > err = 0; > - index = get_slot(vlan, NULL); > rcu_assign_pointer(q->vlan, vlan); > - rcu_assign_pointer(vlan->taps[index], q); > + rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); > sock_hold(&q->sk); > > q->file = file; > + q->queue_index = vlan->numvtaps; > file->private_data = q; > > vlan->numvtaps++; > @@ -140,15 +121,22 @@ out: > */ > static void macvtap_put_queue(struct macvtap_queue *q) > { > + struct macvtap_queue *nq; > struct macvlan_dev *vlan; > > spin_lock(&macvtap_lock); > vlan = rcu_dereference_protected(q->vlan, > lockdep_is_held(&macvtap_lock)); > if (vlan) { > - int index = get_slot(vlan, q); > + int index = q->queue_index; > + BUG_ON(index >= vlan->numvtaps); > + > + nq = rcu_dereference_protected(vlan->taps[vlan->numvtaps - 1], > + lockdep_is_held(&macvtap_lock)); > + rcu_assign_pointer(vlan->taps[index], nq); > + nq->queue_index = index; > > - RCU_INIT_POINTER(vlan->taps[index], NULL); > + RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL); > RCU_INIT_POINTER(q->vlan, NULL); > sock_put(&q->sk); > --vlan->numvtaps; > @@ -182,8 +170,7 @@ static struct macvtap_queue *macvtap_get_queue(struct > net_device *dev, > rxq = skb_get_rxhash(skb); > if (rxq) { > tap = rcu_dereference(vlan->taps[rxq % numvtaps]); > - if (tap) > - goto out; > + goto out; > } > > if (likely(skb_rx_queue_recorded(skb))) { > @@ -193,17 +180,10 @@ static struct macvtap_queue *macvtap_get_queue(struct > net_device *dev, > rxq -= numvtaps; > > tap = rcu_dereference(vlan->taps[rxq]); > - if (tap) > - goto out; > - } > - > - /* Everything failed - find first available queue */ > - for (rxq = 0; rxq < MAX_MACVTAP_QUEUES; rxq++) { > - tap = rcu_dereference(vlan->taps[rxq]); > - if (tap) > - break; > + goto out; > } > > + tap = rcu_dereference(vlan->taps[0]); > out: > return tap; > } > @@ -219,19 +199,15 @@ static void macvtap_del_queues(struct net_device *dev) > struct macvtap_queue *q, *qlist[MAX_MACVTAP_QUEUES]; > int i, j = 0; > > - /* macvtap_put_queue can free some slots, so go through all slots */ > spin_lock(&macvtap_lock); > - for (i = 0; i < MAX_MACVTAP_QUEUES && vlan->numvtaps; i++) { > + for (i = 0; i < vlan->numvtaps; i++) { > q = rcu_dereference_protected(vlan->taps[i], > lockdep_is_held(&macvtap_lock)); > - if (q) { > - qlist[j++] = q; > - RCU_INIT_POINTER(vlan->taps[i], NULL); > - RCU_INIT_POINTER(q->vlan, NULL); > - vlan->numvtaps--; > - } > + BUG_ON(q == NULL); > + qlist[j++] = q; > + RCU_INIT_POINTER(vlan->taps[i], NULL); > + RCU_INIT_POINTER(q->vlan, NULL); > } > - BUG_ON(vlan->numvtaps != 0); > /* guarantee that any future macvtap_set_queue will fail */ > vlan->numvtaps = MAX_MACVTAP_QUEUES; > spin_unlock(&macvtap_lock); > -- > 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
