pkt_sched: Add multiqueue handling to qdisc_graft().

Move the destruction of the old queue into qdisc_graft().

When operating on a root qdisc (ie. "parent == NULL"), apply
the operation to all queues.  The caller has grabbed a single
implicit reference for this graft, therefore when we apply the
change to more than one queue we must grab additional qdisc
references.

Otherwise, we are operating on a class of a specific parent qdisc, and
therefore no multiqueue handling is necessary.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 59 insertions, 42 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 74924893ef7f..b3ef8307204e 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -435,28 +435,22 @@ static u32 qdisc_alloc_handle(struct net_device *dev)
         return i>0 ? autohandle : 0;
 }
 
-/* Attach toplevel qdisc to device dev */
+/* Attach toplevel qdisc to device queue. */
 
-static struct Qdisc *
-dev_graft_qdisc(struct net_device *dev, struct Qdisc *qdisc)
+static struct Qdisc *dev_graft_qdisc(struct netdev_queue *dev_queue,
+                                     struct Qdisc *qdisc)
 {
-        struct netdev_queue *dev_queue;
         spinlock_t *root_lock;
         struct Qdisc *oqdisc;
         int ingress;
 
-        if (dev->flags & IFF_UP)
-                dev_deactivate(dev);
-
         ingress = 0;
         if (qdisc && qdisc->flags&TCQ_F_INGRESS)
                 ingress = 1;
 
         if (ingress) {
-                dev_queue = &dev->rx_queue;
                 oqdisc = dev_queue->qdisc;
         } else {
-                dev_queue = netdev_get_tx_queue(dev, 0);
                 oqdisc = dev_queue->qdisc_sleeping;
         }
 
@@ -487,9 +481,6 @@ dev_graft_qdisc(struct net_device *dev, struct Qdisc *qdisc)
 
         spin_unlock_bh(root_lock);
 
-        if (dev->flags & IFF_UP)
-                dev_activate(dev);
-
         return oqdisc;
 }
 
@@ -521,26 +512,66 @@ void qdisc_tree_decrease_qlen(struct Qdisc *sch, unsigned int n)
 }
 EXPORT_SYMBOL(qdisc_tree_decrease_qlen);
 
-/* Graft qdisc "new" to class "classid" of qdisc "parent" or
-   to device "dev".
+static void notify_and_destroy(struct sk_buff *skb, struct nlmsghdr *n, u32 clid,
+                               struct Qdisc *old, struct Qdisc *new)
+{
+        if (new || old)
+                qdisc_notify(skb, n, clid, old, new);
 
-   Old qdisc is not destroyed but returned in *old.
+        if (old) {
+                spin_lock_bh(&old->q.lock);
+                qdisc_destroy(old);
+                spin_unlock_bh(&old->q.lock);
+        }
+}
+
+/* Graft qdisc "new" to class "classid" of qdisc "parent" or
+ * to device "dev".
+ *
+ * When appropriate send a netlink notification using 'skb'
+ * and "n".
+ *
+ * On success, destroy old qdisc.
  */
 
 static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
-                       u32 classid,
-                       struct Qdisc *new, struct Qdisc **old)
+                       struct sk_buff *skb, struct nlmsghdr *n, u32 classid,
+                       struct Qdisc *new, struct Qdisc *old)
 {
+        struct Qdisc *q = old;
         int err = 0;
-        struct Qdisc *q = *old;
-
 
         if (parent == NULL) {
-                if (q && q->flags&TCQ_F_INGRESS) {
-                        *old = dev_graft_qdisc(dev, q);
-                } else {
-                        *old = dev_graft_qdisc(dev, new);
+                unsigned int i, num_q, ingress;
+
+                ingress = 0;
+                num_q = dev->num_tx_queues;
+                if (q && q->flags & TCQ_F_INGRESS) {
+                        num_q = 1;
+                        ingress = 1;
                 }
+
+                if (dev->flags & IFF_UP)
+                        dev_deactivate(dev);
+
+                for (i = 0; i < num_q; i++) {
+                        struct netdev_queue *dev_queue = &dev->rx_queue;
+
+                        if (!ingress)
+                                dev_queue = netdev_get_tx_queue(dev, i);
+
+                        if (ingress) {
+                                old = dev_graft_qdisc(dev_queue, q);
+                        } else {
+                                old = dev_graft_qdisc(dev_queue, new);
+                                if (new && i > 0)
+                                        atomic_inc(&new->refcnt);
+                        }
+                        notify_and_destroy(skb, n, classid, old, new);
+                }
+
+                if (dev->flags & IFF_UP)
+                        dev_activate(dev);
         } else {
                 const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
 
@@ -549,10 +580,12 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
                 if (cops) {
                         unsigned long cl = cops->get(parent, classid);
                         if (cl) {
-                                err = cops->graft(parent, cl, new, old);
+                                err = cops->graft(parent, cl, new, &old);
                                 cops->put(parent, cl);
                         }
                 }
+                if (!err)
+                        notify_and_destroy(skb, n, classid, old, new);
         }
         return err;
 }
@@ -773,16 +806,8 @@ static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
                         return -EINVAL;
                 if (q->handle == 0)
                         return -ENOENT;
-                if ((err = qdisc_graft(dev, p, clid, NULL, &q)) != 0)
+                if ((err = qdisc_graft(dev, p, skb, n, clid, NULL, q)) != 0)
                         return err;
-                if (q) {
-                        spinlock_t *root_lock = qdisc_root_lock(q);
-
-                        qdisc_notify(skb, n, clid, q, NULL);
-                        spin_unlock_bh(root_lock);
-                        qdisc_destroy(q);
-                        spin_unlock_bh(root_lock);
-                }
         } else {
                 qdisc_notify(skb, n, clid, NULL, q);
         }
@@ -923,10 +948,9 @@ create_n_graft:
 
 graft:
         if (1) {
-                struct Qdisc *old_q = NULL;
                 spinlock_t *root_lock;
 
-                err = qdisc_graft(dev, p, clid, q, &old_q);
+                err = qdisc_graft(dev, p, skb, n, clid, q, NULL);
                 if (err) {
                         if (q) {
                                 root_lock = qdisc_root_lock(q);
@@ -936,13 +960,6 @@ graft:
                         }
                         return err;
                 }
-                qdisc_notify(skb, n, clid, old_q, q);
-                if (old_q) {
-                        root_lock = qdisc_root_lock(old_q);
-                        spin_lock_bh(root_lock);
-                        qdisc_destroy(old_q);
-                        spin_unlock_bh(root_lock);
-                }
         }
         return 0;
 }