linux/drivers/net/xen-netback/interface.c
Wei Liu f7b50c4e7c xen-netback: bookkeep number of active queues in our own module
The original code uses netdev->real_num_tx_queues to bookkeep number of
queues and invokes netif_set_real_num_tx_queues to set the number of
queues. However, netif_set_real_num_tx_queues doesn't allow
real_num_tx_queues to be smaller than 1, which means setting the number
to 0 will not work and real_num_tx_queues is untouched.

This is bogus when xenvif_free is invoked before any number of queues is
allocated. That function needs to iterate through all queues to free
resources. Using the wrong number of queues results in NULL pointer
dereference.

So we bookkeep the number of queues in xen-netback to solve this
problem. This fixes a regression introduced by multiqueue patchset in
3.16-rc1.

There's another bug in original code that the real number of RX queues
is never set. In current Xen multiqueue design, the number of TX queues
and RX queues are in fact the same. We need to set the numbers of TX and
RX queues to the same value.

Also remove xenvif_select_queue and leave queue selection to core
driver, as suggested by David Miller.

Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-25 15:59:47 -07:00

735 lines
19 KiB
C

/*
* Network-device interface management.
*
* Copyright (c) 2004-2005, Keir Fraser
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "common.h"
#include <linux/kthread.h>
#include <linux/ethtool.h>
#include <linux/rtnetlink.h>
#include <linux/if_vlan.h>
#include <linux/vmalloc.h>
#include <xen/events.h>
#include <asm/xen/hypercall.h>
#include <xen/balloon.h>
#define XENVIF_QUEUE_LENGTH 32
#define XENVIF_NAPI_WEIGHT 64
static inline void xenvif_stop_queue(struct xenvif_queue *queue)
{
struct net_device *dev = queue->vif->dev;
if (!queue->vif->can_queue)
return;
netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
}
int xenvif_schedulable(struct xenvif *vif)
{
return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
}
static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
{
struct xenvif_queue *queue = dev_id;
if (RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))
napi_schedule(&queue->napi);
return IRQ_HANDLED;
}
int xenvif_poll(struct napi_struct *napi, int budget)
{
struct xenvif_queue *queue =
container_of(napi, struct xenvif_queue, napi);
int work_done;
/* This vif is rogue, we pretend we've there is nothing to do
* for this vif to deschedule it from NAPI. But this interface
* will be turned off in thread context later.
*/
if (unlikely(queue->vif->disabled)) {
napi_complete(napi);
return 0;
}
work_done = xenvif_tx_action(queue, budget);
if (work_done < budget) {
napi_complete(napi);
xenvif_napi_schedule_or_enable_events(queue);
}
return work_done;
}
static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
{
struct xenvif_queue *queue = dev_id;
xenvif_kick_thread(queue);
return IRQ_HANDLED;
}
static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
{
xenvif_tx_interrupt(irq, dev_id);
xenvif_rx_interrupt(irq, dev_id);
return IRQ_HANDLED;
}
int xenvif_queue_stopped(struct xenvif_queue *queue)
{
struct net_device *dev = queue->vif->dev;
unsigned int id = queue->id;
return netif_tx_queue_stopped(netdev_get_tx_queue(dev, id));
}
void xenvif_wake_queue(struct xenvif_queue *queue)
{
struct net_device *dev = queue->vif->dev;
unsigned int id = queue->id;
netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
}
/* Callback to wake the queue and drain it on timeout */
static void xenvif_wake_queue_callback(unsigned long data)
{
struct xenvif_queue *queue = (struct xenvif_queue *)data;
if (xenvif_queue_stopped(queue)) {
netdev_err(queue->vif->dev, "draining TX queue\n");
queue->rx_queue_purge = true;
xenvif_kick_thread(queue);
xenvif_wake_queue(queue);
}
}
static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct xenvif *vif = netdev_priv(dev);
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
u16 index;
int min_slots_needed;
BUG_ON(skb->dev != dev);
/* Drop the packet if queues are not set up */
if (num_queues < 1)
goto drop;
/* Obtain the queue to be used to transmit this packet */
index = skb_get_queue_mapping(skb);
if (index >= num_queues) {
pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n.",
index, vif->dev->name);
index %= num_queues;
}
queue = &vif->queues[index];
/* Drop the packet if queue is not ready */
if (queue->task == NULL ||
queue->dealloc_task == NULL ||
!xenvif_schedulable(vif))
goto drop;
/* At best we'll need one slot for the header and one for each
* frag.
*/
min_slots_needed = 1 + skb_shinfo(skb)->nr_frags;
/* If the skb is GSO then we'll also need an extra slot for the
* metadata.
*/
if (skb_is_gso(skb))
min_slots_needed++;
/* If the skb can't possibly fit in the remaining slots
* then turn off the queue to give the ring a chance to
* drain.
*/
if (!xenvif_rx_ring_slots_available(queue, min_slots_needed)) {
queue->wake_queue.function = xenvif_wake_queue_callback;
queue->wake_queue.data = (unsigned long)queue;
xenvif_stop_queue(queue);
mod_timer(&queue->wake_queue,
jiffies + rx_drain_timeout_jiffies);
}
skb_queue_tail(&queue->rx_queue, skb);
xenvif_kick_thread(queue);
return NETDEV_TX_OK;
drop:
vif->dev->stats.tx_dropped++;
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
{
struct xenvif *vif = netdev_priv(dev);
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
unsigned long rx_bytes = 0;
unsigned long rx_packets = 0;
unsigned long tx_bytes = 0;
unsigned long tx_packets = 0;
unsigned int index;
if (vif->queues == NULL)
goto out;
/* Aggregate tx and rx stats from each queue */
for (index = 0; index < num_queues; ++index) {
queue = &vif->queues[index];
rx_bytes += queue->stats.rx_bytes;
rx_packets += queue->stats.rx_packets;
tx_bytes += queue->stats.tx_bytes;
tx_packets += queue->stats.tx_packets;
}
out:
vif->dev->stats.rx_bytes = rx_bytes;
vif->dev->stats.rx_packets = rx_packets;
vif->dev->stats.tx_bytes = tx_bytes;
vif->dev->stats.tx_packets = tx_packets;
return &vif->dev->stats;
}
static void xenvif_up(struct xenvif *vif)
{
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
unsigned int queue_index;
for (queue_index = 0; queue_index < num_queues; ++queue_index) {
queue = &vif->queues[queue_index];
napi_enable(&queue->napi);
enable_irq(queue->tx_irq);
if (queue->tx_irq != queue->rx_irq)
enable_irq(queue->rx_irq);
xenvif_napi_schedule_or_enable_events(queue);
}
}
static void xenvif_down(struct xenvif *vif)
{
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
unsigned int queue_index;
for (queue_index = 0; queue_index < num_queues; ++queue_index) {
queue = &vif->queues[queue_index];
napi_disable(&queue->napi);
disable_irq(queue->tx_irq);
if (queue->tx_irq != queue->rx_irq)
disable_irq(queue->rx_irq);
del_timer_sync(&queue->credit_timeout);
}
}
static int xenvif_open(struct net_device *dev)
{
struct xenvif *vif = netdev_priv(dev);
if (netif_carrier_ok(dev))
xenvif_up(vif);
netif_tx_start_all_queues(dev);
return 0;
}
static int xenvif_close(struct net_device *dev)
{
struct xenvif *vif = netdev_priv(dev);
if (netif_carrier_ok(dev))
xenvif_down(vif);
netif_tx_stop_all_queues(dev);
return 0;
}
static int xenvif_change_mtu(struct net_device *dev, int mtu)
{
struct xenvif *vif = netdev_priv(dev);
int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
if (mtu > max)
return -EINVAL;
dev->mtu = mtu;
return 0;
}
static netdev_features_t xenvif_fix_features(struct net_device *dev,
netdev_features_t features)
{
struct xenvif *vif = netdev_priv(dev);
if (!vif->can_sg)
features &= ~NETIF_F_SG;
if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV4))
features &= ~NETIF_F_TSO;
if (~(vif->gso_mask | vif->gso_prefix_mask) & GSO_BIT(TCPV6))
features &= ~NETIF_F_TSO6;
if (!vif->ip_csum)
features &= ~NETIF_F_IP_CSUM;
if (!vif->ipv6_csum)
features &= ~NETIF_F_IPV6_CSUM;
return features;
}
static const struct xenvif_stat {
char name[ETH_GSTRING_LEN];
u16 offset;
} xenvif_stats[] = {
{
"rx_gso_checksum_fixup",
offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
},
/* If (sent != success + fail), there are probably packets never
* freed up properly!
*/
{
"tx_zerocopy_sent",
offsetof(struct xenvif_stats, tx_zerocopy_sent),
},
{
"tx_zerocopy_success",
offsetof(struct xenvif_stats, tx_zerocopy_success),
},
{
"tx_zerocopy_fail",
offsetof(struct xenvif_stats, tx_zerocopy_fail)
},
/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
* a guest with the same MAX_SKB_FRAG
*/
{
"tx_frag_overflow",
offsetof(struct xenvif_stats, tx_frag_overflow)
},
};
static int xenvif_get_sset_count(struct net_device *dev, int string_set)
{
switch (string_set) {
case ETH_SS_STATS:
return ARRAY_SIZE(xenvif_stats);
default:
return -EINVAL;
}
}
static void xenvif_get_ethtool_stats(struct net_device *dev,
struct ethtool_stats *stats, u64 * data)
{
struct xenvif *vif = netdev_priv(dev);
unsigned int num_queues = vif->num_queues;
int i;
unsigned int queue_index;
struct xenvif_stats *vif_stats;
for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
unsigned long accum = 0;
for (queue_index = 0; queue_index < num_queues; ++queue_index) {
vif_stats = &vif->queues[queue_index].stats;
accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
}
data[i] = accum;
}
}
static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
{
int i;
switch (stringset) {
case ETH_SS_STATS:
for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
memcpy(data + i * ETH_GSTRING_LEN,
xenvif_stats[i].name, ETH_GSTRING_LEN);
break;
}
}
static const struct ethtool_ops xenvif_ethtool_ops = {
.get_link = ethtool_op_get_link,
.get_sset_count = xenvif_get_sset_count,
.get_ethtool_stats = xenvif_get_ethtool_stats,
.get_strings = xenvif_get_strings,
};
static const struct net_device_ops xenvif_netdev_ops = {
.ndo_start_xmit = xenvif_start_xmit,
.ndo_get_stats = xenvif_get_stats,
.ndo_open = xenvif_open,
.ndo_stop = xenvif_close,
.ndo_change_mtu = xenvif_change_mtu,
.ndo_fix_features = xenvif_fix_features,
.ndo_set_mac_address = eth_mac_addr,
.ndo_validate_addr = eth_validate_addr,
};
struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
unsigned int handle)
{
int err;
struct net_device *dev;
struct xenvif *vif;
char name[IFNAMSIZ] = {};
snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
/* Allocate a netdev with the max. supported number of queues.
* When the guest selects the desired number, it will be updated
* via netif_set_real_num_*_queues().
*/
dev = alloc_netdev_mq(sizeof(struct xenvif), name, ether_setup,
xenvif_max_queues);
if (dev == NULL) {
pr_warn("Could not allocate netdev for %s\n", name);
return ERR_PTR(-ENOMEM);
}
SET_NETDEV_DEV(dev, parent);
vif = netdev_priv(dev);
vif->domid = domid;
vif->handle = handle;
vif->can_sg = 1;
vif->ip_csum = 1;
vif->dev = dev;
vif->disabled = false;
/* Start out with no queues. */
vif->queues = NULL;
vif->num_queues = 0;
dev->netdev_ops = &xenvif_netdev_ops;
dev->hw_features = NETIF_F_SG |
NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
NETIF_F_TSO | NETIF_F_TSO6;
dev->features = dev->hw_features | NETIF_F_RXCSUM;
dev->ethtool_ops = &xenvif_ethtool_ops;
dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
/*
* Initialise a dummy MAC address. We choose the numerically
* largest non-broadcast address to prevent the address getting
* stolen by an Ethernet bridge for STP purposes.
* (FE:FF:FF:FF:FF:FF)
*/
memset(dev->dev_addr, 0xFF, ETH_ALEN);
dev->dev_addr[0] &= ~0x01;
netif_carrier_off(dev);
err = register_netdev(dev);
if (err) {
netdev_warn(dev, "Could not register device: err=%d\n", err);
free_netdev(dev);
return ERR_PTR(err);
}
netdev_dbg(dev, "Successfully created xenvif\n");
__module_get(THIS_MODULE);
return vif;
}
int xenvif_init_queue(struct xenvif_queue *queue)
{
int err, i;
queue->credit_bytes = queue->remaining_credit = ~0UL;
queue->credit_usec = 0UL;
init_timer(&queue->credit_timeout);
queue->credit_window_start = get_jiffies_64();
skb_queue_head_init(&queue->rx_queue);
skb_queue_head_init(&queue->tx_queue);
queue->pending_cons = 0;
queue->pending_prod = MAX_PENDING_REQS;
for (i = 0; i < MAX_PENDING_REQS; ++i)
queue->pending_ring[i] = i;
spin_lock_init(&queue->callback_lock);
spin_lock_init(&queue->response_lock);
/* If ballooning is disabled, this will consume real memory, so you
* better enable it. The long term solution would be to use just a
* bunch of valid page descriptors, without dependency on ballooning
*/
err = alloc_xenballooned_pages(MAX_PENDING_REQS,
queue->mmap_pages,
false);
if (err) {
netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
return -ENOMEM;
}
for (i = 0; i < MAX_PENDING_REQS; i++) {
queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
{ .callback = xenvif_zerocopy_callback,
.ctx = NULL,
.desc = i };
queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
}
init_timer(&queue->wake_queue);
netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
XENVIF_NAPI_WEIGHT);
return 0;
}
void xenvif_carrier_on(struct xenvif *vif)
{
rtnl_lock();
if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
dev_set_mtu(vif->dev, ETH_DATA_LEN);
netdev_update_features(vif->dev);
netif_carrier_on(vif->dev);
if (netif_running(vif->dev))
xenvif_up(vif);
rtnl_unlock();
}
int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
unsigned long rx_ring_ref, unsigned int tx_evtchn,
unsigned int rx_evtchn)
{
struct task_struct *task;
int err = -ENOMEM;
BUG_ON(queue->tx_irq);
BUG_ON(queue->task);
BUG_ON(queue->dealloc_task);
err = xenvif_map_frontend_rings(queue, tx_ring_ref, rx_ring_ref);
if (err < 0)
goto err;
init_waitqueue_head(&queue->wq);
init_waitqueue_head(&queue->dealloc_wq);
if (tx_evtchn == rx_evtchn) {
/* feature-split-event-channels == 0 */
err = bind_interdomain_evtchn_to_irqhandler(
queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
queue->name, queue);
if (err < 0)
goto err_unmap;
queue->tx_irq = queue->rx_irq = err;
disable_irq(queue->tx_irq);
} else {
/* feature-split-event-channels == 1 */
snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
"%s-tx", queue->name);
err = bind_interdomain_evtchn_to_irqhandler(
queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
queue->tx_irq_name, queue);
if (err < 0)
goto err_unmap;
queue->tx_irq = err;
disable_irq(queue->tx_irq);
snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
"%s-rx", queue->name);
err = bind_interdomain_evtchn_to_irqhandler(
queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
queue->rx_irq_name, queue);
if (err < 0)
goto err_tx_unbind;
queue->rx_irq = err;
disable_irq(queue->rx_irq);
}
task = kthread_create(xenvif_kthread_guest_rx,
(void *)queue, "%s-guest-rx", queue->name);
if (IS_ERR(task)) {
pr_warn("Could not allocate kthread for %s\n", queue->name);
err = PTR_ERR(task);
goto err_rx_unbind;
}
queue->task = task;
task = kthread_create(xenvif_dealloc_kthread,
(void *)queue, "%s-dealloc", queue->name);
if (IS_ERR(task)) {
pr_warn("Could not allocate kthread for %s\n", queue->name);
err = PTR_ERR(task);
goto err_rx_unbind;
}
queue->dealloc_task = task;
wake_up_process(queue->task);
wake_up_process(queue->dealloc_task);
return 0;
err_rx_unbind:
unbind_from_irqhandler(queue->rx_irq, queue);
queue->rx_irq = 0;
err_tx_unbind:
unbind_from_irqhandler(queue->tx_irq, queue);
queue->tx_irq = 0;
err_unmap:
xenvif_unmap_frontend_rings(queue);
err:
module_put(THIS_MODULE);
return err;
}
void xenvif_carrier_off(struct xenvif *vif)
{
struct net_device *dev = vif->dev;
rtnl_lock();
netif_carrier_off(dev); /* discard queued packets */
if (netif_running(dev))
xenvif_down(vif);
rtnl_unlock();
}
static void xenvif_wait_unmap_timeout(struct xenvif_queue *queue,
unsigned int worst_case_skb_lifetime)
{
int i, unmap_timeout = 0;
for (i = 0; i < MAX_PENDING_REQS; ++i) {
if (queue->grant_tx_handle[i] != NETBACK_INVALID_HANDLE) {
unmap_timeout++;
schedule_timeout(msecs_to_jiffies(1000));
if (unmap_timeout > worst_case_skb_lifetime &&
net_ratelimit())
netdev_err(queue->vif->dev,
"Page still granted! Index: %x\n",
i);
i = -1;
}
}
}
void xenvif_disconnect(struct xenvif *vif)
{
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
unsigned int queue_index;
if (netif_carrier_ok(vif->dev))
xenvif_carrier_off(vif);
for (queue_index = 0; queue_index < num_queues; ++queue_index) {
queue = &vif->queues[queue_index];
if (queue->task) {
del_timer_sync(&queue->wake_queue);
kthread_stop(queue->task);
queue->task = NULL;
}
if (queue->dealloc_task) {
kthread_stop(queue->dealloc_task);
queue->dealloc_task = NULL;
}
if (queue->tx_irq) {
if (queue->tx_irq == queue->rx_irq)
unbind_from_irqhandler(queue->tx_irq, queue);
else {
unbind_from_irqhandler(queue->tx_irq, queue);
unbind_from_irqhandler(queue->rx_irq, queue);
}
queue->tx_irq = 0;
}
xenvif_unmap_frontend_rings(queue);
}
}
/* Reverse the relevant parts of xenvif_init_queue().
* Used for queue teardown from xenvif_free(), and on the
* error handling paths in xenbus.c:connect().
*/
void xenvif_deinit_queue(struct xenvif_queue *queue)
{
free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages);
netif_napi_del(&queue->napi);
}
void xenvif_free(struct xenvif *vif)
{
struct xenvif_queue *queue = NULL;
unsigned int num_queues = vif->num_queues;
unsigned int queue_index;
/* Here we want to avoid timeout messages if an skb can be legitimately
* stuck somewhere else. Realistically this could be an another vif's
* internal or QDisc queue. That another vif also has this
* rx_drain_timeout_msecs timeout, but the timer only ditches the
* internal queue. After that, the QDisc queue can put in worst case
* XEN_NETIF_RX_RING_SIZE / MAX_SKB_FRAGS skbs into that another vif's
* internal queue, so we need several rounds of such timeouts until we
* can be sure that no another vif should have skb's from us. We are
* not sending more skb's, so newly stuck packets are not interesting
* for us here.
*/
unsigned int worst_case_skb_lifetime = (rx_drain_timeout_msecs/1000) *
DIV_ROUND_UP(XENVIF_QUEUE_LENGTH, (XEN_NETIF_RX_RING_SIZE / MAX_SKB_FRAGS));
unregister_netdev(vif->dev);
for (queue_index = 0; queue_index < num_queues; ++queue_index) {
queue = &vif->queues[queue_index];
xenvif_wait_unmap_timeout(queue, worst_case_skb_lifetime);
xenvif_deinit_queue(queue);
}
vfree(vif->queues);
vif->queues = NULL;
vif->num_queues = 0;
free_netdev(vif->dev);
module_put(THIS_MODULE);
}