From: Scott Feldman <sfel...@gmail.com>

v2:

Changes based on review:

- David Miller <da...@davemloft.net> raise problem with system_wq not
  preserving queue order to execution order.  To fix, use driver-private
  ordered workqueue to preserve ordering of queued work.

- Jiri Pirko <j...@resnulli.us> small change on kfree of work queue item.

v1:

In review of Simon's patchset "rocker: transaction fixes". it was noted
that rocker->neigh_tbl_next_index was unprotected in the call path below
and could race with other contexts calling rocker_port_ipv4_neigh():

        arp_process()
        neigh_update()
        rocker_neigh_update()
        rocker_port_ipv4_neigh()

To fix, move the neigh_update() event processing to process contexts and
hold rtnl_lock to call rocker_port_ipv4_neigh().  This will protect
rocker->neigh_tbl_next_index accesses and is more consistent with the rest
of the driver code where non-I/O processing is done under process context
with rtnl_lock held.

Signed-off-by: Scott Feldman <sfel...@gmail.com>
Acked-by: Jiri Pirko <j...@resnulli.us>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
---
 drivers/net/ethernet/rocker/rocker.c |   71 +++++++++++++++++++++++++++++-----
 1 file changed, 62 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/rocker/rocker.c 
b/drivers/net/ethernet/rocker/rocker.c
index 819289e..aaf5e38 100644
--- a/drivers/net/ethernet/rocker/rocker.c
+++ b/drivers/net/ethernet/rocker/rocker.c
@@ -240,6 +240,9 @@ struct rocker {
        spinlock_t cmd_ring_lock;               /* for cmd ring accesses */
        struct rocker_dma_ring_info cmd_ring;
        struct rocker_dma_ring_info event_ring;
+       struct workqueue_struct *wq;            /* ordered workqueue for
+                                                * async processing
+                                                */
        DECLARE_HASHTABLE(flow_tbl, 16);
        spinlock_t flow_tbl_lock;               /* for flow tbl accesses */
        u64 flow_tbl_next_cookie;
@@ -1464,7 +1467,7 @@ static void rocker_event_mac_vlan_seen_work(struct 
work_struct *work)
                        sw->addr, sw->vlan_id, sw->flags);
        rtnl_unlock();
 
-       kfree(work);
+       kfree(sw);
 }
 
 static int rocker_event_mac_vlan_seen(const struct rocker *rocker,
@@ -1508,7 +1511,7 @@ static int rocker_event_mac_vlan_seen(const struct rocker 
*rocker,
        ether_addr_copy(sw->addr, addr);
        sw->vlan_id = vlan_id;
 
-       schedule_work(&sw->work);
+       queue_work(rocker_port->rocker->wq, &sw->work);
 
        return 0;
 }
@@ -3523,6 +3526,7 @@ static int rocker_port_fdb_learn(struct rocker_port 
*rocker_port,
                                 enum switchdev_trans trans, int flags,
                                 const u8 *addr, __be16 vlan_id)
 {
+       struct rocker *rocker = rocker_port->rocker;
        struct rocker_fdb_learn_work *lw;
        enum rocker_of_dpa_table_id goto_tbl =
                ROCKER_OF_DPA_TABLE_ID_ACL_POLICY;
@@ -3565,7 +3569,7 @@ static int rocker_port_fdb_learn(struct rocker_port 
*rocker_port,
        if (trans == SWITCHDEV_TRANS_PREPARE)
                rocker_port_kfree(trans, lw);
        else
-               schedule_work(&lw->work);
+               queue_work(rocker->wq, &lw->work);
 
        return 0;
 }
@@ -4962,6 +4966,12 @@ static int rocker_probe(struct pci_dev *pdev, const 
struct pci_device_id *id)
        if (!rocker)
                return -ENOMEM;
 
+       rocker->wq = alloc_ordered_workqueue("rocker", 0);
+       if (!rocker->wq) {
+               dev_err(&pdev->dev, "allocate workqueue failed\n");
+               goto err_wq;
+       }
+
        err = pci_enable_device(pdev);
        if (err) {
                dev_err(&pdev->dev, "pci_enable_device failed\n");
@@ -5081,6 +5091,8 @@ err_pci_set_dma_mask:
 err_pci_request_regions:
        pci_disable_device(pdev);
 err_pci_enable_device:
+       destroy_workqueue(rocker->wq);
+err_wq:
        kfree(rocker);
        return err;
 }
@@ -5099,6 +5111,7 @@ static void rocker_remove(struct pci_dev *pdev)
        iounmap(rocker->hw_addr);
        pci_release_regions(rocker->pdev);
        pci_disable_device(rocker->pdev);
+       destroy_workqueue(rocker->wq);
        kfree(rocker);
 }
 
@@ -5224,14 +5237,54 @@ static struct notifier_block rocker_netdevice_nb 
__read_mostly = {
  * Net event notifier event handler
  ************************************/
 
-static int rocker_neigh_update(struct net_device *dev, struct neighbour *n)
+struct rocker_neigh_update_work {
+       struct work_struct work;
+       struct rocker_port *rocker_port;
+       int flags;
+       __be32 ip_addr;
+       unsigned char ha[ALIGN(MAX_ADDR_LEN, sizeof(unsigned long))];
+};
+
+static void rocker_event_neigh_update_work(struct work_struct *work)
+{
+       struct rocker_neigh_update_work *nw =
+               container_of(work, struct rocker_neigh_update_work, work);
+       int err;
+
+       rtnl_lock();
+       err = rocker_port_ipv4_neigh(nw->rocker_port, SWITCHDEV_TRANS_NONE,
+                                    nw->flags, nw->ip_addr, nw->ha);
+       rtnl_unlock();
+
+       if (err)
+               netdev_warn(nw->rocker_port->dev,
+                           "failed to handle neigh %pI4 update (err %d)\n",
+                           &nw->ip_addr, err);
+
+       kfree(nw);
+}
+
+static int rocker_event_neigh_update(struct net_device *dev,
+                                    struct neighbour *n)
 {
        struct rocker_port *rocker_port = netdev_priv(dev);
-       int flags = (n->nud_state & NUD_VALID) ? 0 : ROCKER_OP_FLAG_REMOVE;
-       __be32 ip_addr = *(__be32 *)n->primary_key;
+       struct rocker *rocker = rocker_port->rocker;
+       struct rocker_neigh_update_work *nw;
 
-       return rocker_port_ipv4_neigh(rocker_port, SWITCHDEV_TRANS_NONE,
-                                     flags, ip_addr, n->ha);
+       nw = kmalloc(sizeof(*nw), GFP_ATOMIC);
+       if (!nw)
+               return -ENOMEM;
+
+       INIT_WORK(&nw->work, rocker_event_neigh_update_work);
+
+       nw->rocker_port = rocker_port;
+       nw->flags = (n->nud_state & NUD_VALID) ? 0 : ROCKER_OP_FLAG_REMOVE;
+       nw->ip_addr = *(__be32 *)n->primary_key;
+       memcpy(nw->ha, n->ha, sizeof(nw->ha));
+
+       queue_work(rocker->wq, &nw->work);
+
+       return 0;
 }
 
 static int rocker_netevent_event(struct notifier_block *unused,
@@ -5248,7 +5301,7 @@ static int rocker_netevent_event(struct notifier_block 
*unused,
                dev = n->dev;
                if (!rocker_port_dev_check(dev))
                        return NOTIFY_DONE;
-               err = rocker_neigh_update(dev, n);
+               err = rocker_event_neigh_update(dev, n);
                if (err)
                        netdev_warn(dev,
                                    "failed to handle neigh update (err %d)\n",
-- 
1.7.10.4

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