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Merge branch 'xen-netfront'
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David Vrabel says:

====================
xen-netfront: fix resume regressions in 3.16-rc1

The introduction of multi-queue support to xen-netfront in 3.16-rc1,
broke resume/migration.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Jun 21, 2014
2 parents a705a90 + ce58725 commit 7f08231
Showing 1 changed file with 75 additions and 34 deletions.
109 changes: 75 additions & 34 deletions drivers/net/xen-netfront.c
Original file line number Diff line number Diff line change
Expand Up @@ -1287,7 +1287,7 @@ static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)

if (likely(netif_carrier_ok(dev) &&
RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
napi_schedule(&queue->napi);
napi_schedule(&queue->napi);

return IRQ_HANDLED;
}
Expand Down Expand Up @@ -1437,10 +1437,11 @@ static void xennet_end_access(int ref, void *page)
static void xennet_disconnect_backend(struct netfront_info *info)
{
unsigned int i = 0;
struct netfront_queue *queue = NULL;
unsigned int num_queues = info->netdev->real_num_tx_queues;

for (i = 0; i < num_queues; ++i) {
struct netfront_queue *queue = &info->queues[i];

/* Stop old i/f to prevent errors whilst we rebuild the state. */
spin_lock_bh(&queue->rx_lock);
spin_lock_irq(&queue->tx_lock);
Expand Down Expand Up @@ -1698,8 +1699,6 @@ static int xennet_init_queue(struct netfront_queue *queue)
goto exit_free_tx;
}

netif_napi_add(queue->info->netdev, &queue->napi, xennet_poll, 64);

return 0;

exit_free_tx:
Expand Down Expand Up @@ -1790,6 +1789,70 @@ static int write_queue_xenstore_keys(struct netfront_queue *queue,
return err;
}

static void xennet_destroy_queues(struct netfront_info *info)
{
unsigned int i;

rtnl_lock();

for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
struct netfront_queue *queue = &info->queues[i];

if (netif_running(info->netdev))
napi_disable(&queue->napi);
netif_napi_del(&queue->napi);
}

rtnl_unlock();

kfree(info->queues);
info->queues = NULL;
}

static int xennet_create_queues(struct netfront_info *info,
unsigned int num_queues)
{
unsigned int i;
int ret;

info->queues = kcalloc(num_queues, sizeof(struct netfront_queue),
GFP_KERNEL);
if (!info->queues)
return -ENOMEM;

rtnl_lock();

for (i = 0; i < num_queues; i++) {
struct netfront_queue *queue = &info->queues[i];

queue->id = i;
queue->info = info;

ret = xennet_init_queue(queue);
if (ret < 0) {
dev_warn(&info->netdev->dev, "only created %d queues\n",
num_queues);
num_queues = i;
break;
}

netif_napi_add(queue->info->netdev, &queue->napi,
xennet_poll, 64);
if (netif_running(info->netdev))
napi_enable(&queue->napi);
}

netif_set_real_num_tx_queues(info->netdev, num_queues);

rtnl_unlock();

if (num_queues == 0) {
dev_err(&info->netdev->dev, "no queues\n");
return -EINVAL;
}
return 0;
}

/* Common code used when first setting up, and when resuming. */
static int talk_to_netback(struct xenbus_device *dev,
struct netfront_info *info)
Expand Down Expand Up @@ -1826,42 +1889,20 @@ static int talk_to_netback(struct xenbus_device *dev,
goto out;
}

/* Allocate array of queues */
info->queues = kcalloc(num_queues, sizeof(struct netfront_queue), GFP_KERNEL);
if (!info->queues) {
err = -ENOMEM;
goto out;
}
rtnl_lock();
netif_set_real_num_tx_queues(info->netdev, num_queues);
rtnl_unlock();
if (info->queues)
xennet_destroy_queues(info);

err = xennet_create_queues(info, num_queues);
if (err < 0)
goto destroy_ring;

/* Create shared ring, alloc event channel -- for each queue */
for (i = 0; i < num_queues; ++i) {
queue = &info->queues[i];
queue->id = i;
queue->info = info;
err = xennet_init_queue(queue);
if (err) {
/* xennet_init_queue() cleans up after itself on failure,
* but we still have to clean up any previously initialised
* queues. If i > 0, set num_queues to i, then goto
* destroy_ring, which calls xennet_disconnect_backend()
* to tidy up.
*/
if (i > 0) {
rtnl_lock();
netif_set_real_num_tx_queues(info->netdev, i);
rtnl_unlock();
goto destroy_ring;
} else {
goto out;
}
}
err = setup_netfront(dev, queue, feature_split_evtchn);
if (err) {
/* As for xennet_init_queue(), setup_netfront() will tidy
* up the current queue on error, but we need to clean up
/* setup_netfront() will tidy up the current
* queue on error, but we need to clean up
* those already allocated.
*/
if (i > 0) {
Expand Down

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