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IPoIB: Use netif_tx_lock() and get rid of private tx_lock, LLTX

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Currently, IPoIB is an LLTX driver that uses its own IRQ-disabling
tx_lock.  Not only do we want to get rid of LLTX, this actually causes
problems because of the skb_orphan() done with this tx_lock held: some
skb destructors expect to be run with interrupts enabled.

The simplest fix for this is to get rid of the driver-private tx_lock
and stop using LLTX.  We kill off priv->tx_lock and use
netif_tx_lock[_bh]() instead; the patch to do this is a tiny bit
tricky because we need to update places that take priv->lock inside
the tx_lock to disable IRQs, rather than relying on tx_lock having
already disabled IRQs.

Also, there are a couple of places where we need to disable BHs to
make sure we have a consistent context to call netif_tx_lock() (since
we no longer can use _irqsave() variants), and we also have to change
ipoib_send_comp_handler() to call drain_tx_cq() through a timer rather
than directly, because ipoib_send_comp_handler() runs in interrupt
context and drain_tx_cq() must run in BH context so it can call
netif_tx_lock().

Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Roland Dreier
2008-09-30 10:36:21 -07:00
parent c9da4bad5b
commit 943c246e9b
5 changed files with 118 additions and 107 deletions
Download Patch File Download Diff File Expand all files Collapse all files

68
drivers/infiniband/ulp/ipoib/ipoib_main.c
View File

@@ -373,9 +373,10 @@ void ipoib_flush_paths(struct net_device *dev)
struct ipoib_dev_priv *priv = netdev_priv(dev);
struct ipoib_path *path, *tp;
LIST_HEAD(remove_list);
unsigned long flags;
spin_lock_irq(&priv->tx_lock);
spin_lock(&priv->lock);
netif_tx_lock_bh(dev);
spin_lock_irqsave(&priv->lock, flags);
list_splice_init(&priv->path_list, &remove_list);
@@ -385,15 +386,16 @@ void ipoib_flush_paths(struct net_device *dev)
list_for_each_entry_safe(path, tp, &remove_list, list) {
if (path->query)
ib_sa_cancel_query(path->query_id, path->query);
spin_unlock(&priv->lock);
spin_unlock_irq(&priv->tx_lock);
spin_unlock_irqrestore(&priv->lock, flags);
netif_tx_unlock_bh(dev);
wait_for_completion(&path->done);
path_free(dev, path);
spin_lock_irq(&priv->tx_lock);
spin_lock(&priv->lock);
netif_tx_lock_bh(dev);
spin_lock_irqsave(&priv->lock, flags);
}
spin_unlock(&priv->lock);
spin_unlock_irq(&priv->tx_lock);
spin_unlock_irqrestore(&priv->lock, flags);
netif_tx_unlock_bh(dev);
}
static void path_rec_completion(int status,
@@ -555,6 +557,7 @@ static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
struct ipoib_dev_priv *priv = netdev_priv(dev);
struct ipoib_path *path;
struct ipoib_neigh *neigh;
unsigned long flags;
neigh = ipoib_neigh_alloc(skb->dst->neighbour, skb->dev);
if (!neigh) {
@@ -563,11 +566,7 @@ static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
return;
}
/*
* We can only be called from ipoib_start_xmit, so we're
* inside tx_lock -- no need to save/restore flags.
*/
spin_lock(&priv->lock);
spin_lock_irqsave(&priv->lock, flags);
path = __path_find(dev, skb->dst->neighbour->ha + 4);
if (!path) {
@@ -614,7 +613,7 @@ static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
__skb_queue_tail(&neigh->queue, skb);
}
spin_unlock(&priv->lock);
spin_unlock_irqrestore(&priv->lock, flags);
return;
err_list:
@@ -626,7 +625,7 @@ err_drop:
++dev->stats.tx_dropped;
dev_kfree_skb_any(skb);
spin_unlock(&priv->lock);
spin_unlock_irqrestore(&priv->lock, flags);
}
static void ipoib_path_lookup(struct sk_buff *skb, struct net_device *dev)
@@ -650,12 +649,9 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
struct ipoib_path *path;
unsigned long flags;
/*
* We can only be called from ipoib_start_xmit, so we're
* inside tx_lock -- no need to save/restore flags.
*/
spin_lock(&priv->lock);
spin_lock_irqsave(&priv->lock, flags);
path = __path_find(dev, phdr->hwaddr + 4);
if (!path || !path->valid) {
@@ -667,7 +663,7 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
__skb_queue_tail(&path->queue, skb);
if (path_rec_start(dev, path)) {
spin_unlock(&priv->lock);
spin_unlock_irqrestore(&priv->lock, flags);
path_free(dev, path);
return;
} else
@@ -677,7 +673,7 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
dev_kfree_skb_any(skb);
}
spin_unlock(&priv->lock);
spin_unlock_irqrestore(&priv->lock, flags);
return;
}
@@ -696,7 +692,7 @@ static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
dev_kfree_skb_any(skb);
}
spin_unlock(&priv->lock);
spin_unlock_irqrestore(&priv->lock, flags);
}
static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
@@ -705,13 +701,10 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
struct ipoib_neigh *neigh;
unsigned long flags;
if (unlikely(!spin_trylock_irqsave(&priv->tx_lock, flags)))
return NETDEV_TX_LOCKED;
if (likely(skb->dst && skb->dst->neighbour)) {
if (unlikely(!*to_ipoib_neigh(skb->dst->neighbour))) {
ipoib_path_lookup(skb, dev);
goto out;
return NETDEV_TX_OK;
}
neigh = *to_ipoib_neigh(skb->dst->neighbour);
@@ -721,7 +714,7 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
skb->dst->neighbour->ha + 4,
sizeof(union ib_gid))) ||
(neigh->dev != dev))) {
spin_lock(&priv->lock);
spin_lock_irqsave(&priv->lock, flags);
/*
* It's safe to call ipoib_put_ah() inside
* priv->lock here, because we know that
@@ -732,25 +725,25 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
ipoib_put_ah(neigh->ah);
list_del(&neigh->list);
ipoib_neigh_free(dev, neigh);
spin_unlock(&priv->lock);
spin_unlock_irqrestore(&priv->lock, flags);
ipoib_path_lookup(skb, dev);
goto out;
return NETDEV_TX_OK;
}
if (ipoib_cm_get(neigh)) {
if (ipoib_cm_up(neigh)) {
ipoib_cm_send(dev, skb, ipoib_cm_get(neigh));
goto out;
return NETDEV_TX_OK;
}
} else if (neigh->ah) {
ipoib_send(dev, skb, neigh->ah, IPOIB_QPN(skb->dst->neighbour->ha));
goto out;
return NETDEV_TX_OK;
}
if (skb_queue_len(&neigh->queue) < IPOIB_MAX_PATH_REC_QUEUE) {
spin_lock(&priv->lock);
spin_lock_irqsave(&priv->lock, flags);
__skb_queue_tail(&neigh->queue, skb);
spin_unlock(&priv->lock);
spin_unlock_irqrestore(&priv->lock, flags);
} else {
++dev->stats.tx_dropped;
dev_kfree_skb_any(skb);
@@ -779,16 +772,13 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
IPOIB_GID_RAW_ARG(phdr->hwaddr + 4));
dev_kfree_skb_any(skb);
++dev->stats.tx_dropped;
goto out;
return NETDEV_TX_OK;
}
unicast_arp_send(skb, dev, phdr);
}
}
out:
spin_unlock_irqrestore(&priv->tx_lock, flags);
return NETDEV_TX_OK;
}
@@ -1052,7 +1042,6 @@ static void ipoib_setup(struct net_device *dev)
dev->type = ARPHRD_INFINIBAND;
dev->tx_queue_len = ipoib_sendq_size * 2;
dev->features = (NETIF_F_VLAN_CHALLENGED |
NETIF_F_LLTX |
NETIF_F_HIGHDMA);
memcpy(dev->broadcast, ipv4_bcast_addr, INFINIBAND_ALEN);
@@ -1064,7 +1053,6 @@ static void ipoib_setup(struct net_device *dev)
ipoib_lro_setup(priv);
spin_lock_init(&priv->lock);
spin_lock_init(&priv->tx_lock);
mutex_init(&priv->vlan_mutex);