Orange Pi5 kernel

/*
 * Copyright (c) 2016 Citrix Systems Inc.
 * Copyright (c) 2002-2005, K A 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 <xen/xen.h>
#include <xen/events.h>
 
/*
 * Update the needed ring page slots for the first SKB queued.
 * Note that any call sequence outside the RX thread calling this function
 * needs to wake up the RX thread via a call of xenvif_kick_thread()
 * afterwards in order to avoid a race with putting the thread to sleep.
 */
static void xenvif_update_needed_slots(struct xenvif_queue *queue,
<------><------><------><------>       const struct sk_buff *skb)
{
<------>unsigned int needed = 0;
 
<------>if (skb) {
<------><------>needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
<------><------>if (skb_is_gso(skb))
<------><------><------>needed++;
<------><------>if (skb->sw_hash)
<------><------><------>needed++;
<------>}
 
<------>WRITE_ONCE(queue->rx_slots_needed, needed);
}
 
static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
{
<------>RING_IDX prod, cons;
<------>unsigned int needed;
 
<------>needed = READ_ONCE(queue->rx_slots_needed);
<------>if (!needed)
<------><------>return false;
 
<------>do {
<------><------>prod = queue->rx.sring->req_prod;
<------><------>cons = queue->rx.req_cons;
 
<------><------>if (prod - cons >= needed)
<------><------><------>return true;
 
<------><------>queue->rx.sring->req_event = prod + 1;
 
<------><------>/* Make sure event is visible before we check prod
<------><------> * again.
<------><------> */
<------><------>mb();
<------>} while (queue->rx.sring->req_prod != prod);
 
<------>return false;
}
 
void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
{
<------>unsigned long flags;
 
<------>spin_lock_irqsave(&queue->rx_queue.lock, flags);
 
<------>if (queue->rx_queue_len >= queue->rx_queue_max) {
<------><------>struct net_device *dev = queue->vif->dev;
 
<------><------>netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
<------><------>kfree_skb(skb);
<------><------>queue->vif->dev->stats.rx_dropped++;
<------>} else {
<------><------>if (skb_queue_empty(&queue->rx_queue))
<------><------><------>xenvif_update_needed_slots(queue, skb);
 
<------><------>__skb_queue_tail(&queue->rx_queue, skb);
 
<------><------>queue->rx_queue_len += skb->len;
<------>}
 
<------>spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
}
 
static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
{
<------>struct sk_buff *skb;
 
<------>spin_lock_irq(&queue->rx_queue.lock);
 
<------>skb = __skb_dequeue(&queue->rx_queue);
<------>if (skb) {
<------><------>xenvif_update_needed_slots(queue, skb_peek(&queue->rx_queue));
 
<------><------>queue->rx_queue_len -= skb->len;
<------><------>if (queue->rx_queue_len < queue->rx_queue_max) {
<------><------><------>struct netdev_queue *txq;
 
<------><------><------>txq = netdev_get_tx_queue(queue->vif->dev, queue->id);
<------><------><------>netif_tx_wake_queue(txq);
<------><------>}
<------>}
 
<------>spin_unlock_irq(&queue->rx_queue.lock);
 
<------>return skb;
}
 
static void xenvif_rx_queue_purge(struct xenvif_queue *queue)
{
<------>struct sk_buff *skb;
 
<------>while ((skb = xenvif_rx_dequeue(queue)) != NULL)
<------><------>kfree_skb(skb);
}
 
static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
{
<------>struct sk_buff *skb;
 
<------>for (;;) {
<------><------>skb = skb_peek(&queue->rx_queue);
<------><------>if (!skb)
<------><------><------>break;
<------><------>if (time_before(jiffies, XENVIF_RX_CB(skb)->expires))
<------><------><------>break;
<------><------>xenvif_rx_dequeue(queue);
<------><------>kfree_skb(skb);
<------><------>queue->vif->dev->stats.rx_dropped++;
<------>}
}
 
static void xenvif_rx_copy_flush(struct xenvif_queue *queue)
{
<------>unsigned int i;
<------>int notify;
 
<------>gnttab_batch_copy(queue->rx_copy.op, queue->rx_copy.num);
 
<------>for (i = 0; i < queue->rx_copy.num; i++) {
<------><------>struct gnttab_copy *op;
 
<------><------>op = &queue->rx_copy.op[i];
 
<------><------>/* If the copy failed, overwrite the status field in
<------><------> * the corresponding response.
<------><------> */
<------><------>if (unlikely(op->status != GNTST_okay)) {
<------><------><------>struct xen_netif_rx_response *rsp;
 
<------><------><------>rsp = RING_GET_RESPONSE(&queue->rx,
<------><------><------><------><------><------>queue->rx_copy.idx[i]);
<------><------><------>rsp->status = op->status;
<------><------>}
<------>}
 
<------>queue->rx_copy.num = 0;
 
<------>/* Push responses for all completed packets. */
<------>RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, notify);
<------>if (notify)
<------><------>notify_remote_via_irq(queue->rx_irq);
 
<------>__skb_queue_purge(queue->rx_copy.completed);
}
 
static void xenvif_rx_copy_add(struct xenvif_queue *queue,
<------><------><------>       struct xen_netif_rx_request *req,
<------><------><------>       unsigned int offset, void *data, size_t len)
{
<------>struct gnttab_copy *op;
<------>struct page *page;
<------>struct xen_page_foreign *foreign;
 
<------>if (queue->rx_copy.num == COPY_BATCH_SIZE)
<------><------>xenvif_rx_copy_flush(queue);
 
<------>op = &queue->rx_copy.op[queue->rx_copy.num];
 
<------>page = virt_to_page(data);
 
<------>op->flags = GNTCOPY_dest_gref;
 
<------>foreign = xen_page_foreign(page);
<------>if (foreign) {
<------><------>op->source.domid = foreign->domid;
<------><------>op->source.u.ref = foreign->gref;
<------><------>op->flags |= GNTCOPY_source_gref;
<------>} else {
<------><------>op->source.u.gmfn = virt_to_gfn(data);
<------><------>op->source.domid  = DOMID_SELF;
<------>}
 
<------>op->source.offset = xen_offset_in_page(data);
<------>op->dest.u.ref    = req->gref;
<------>op->dest.domid    = queue->vif->domid;
<------>op->dest.offset   = offset;
<------>op->len           = len;
 
<------>queue->rx_copy.idx[queue->rx_copy.num] = queue->rx.req_cons;
<------>queue->rx_copy.num++;
}
 
static unsigned int xenvif_gso_type(struct sk_buff *skb)
{
<------>if (skb_is_gso(skb)) {
<------><------>if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
<------><------><------>return XEN_NETIF_GSO_TYPE_TCPV4;
<------><------>else
<------><------><------>return XEN_NETIF_GSO_TYPE_TCPV6;
<------>}
<------>return XEN_NETIF_GSO_TYPE_NONE;
}
 
struct xenvif_pkt_state {
<------>struct sk_buff *skb;
<------>size_t remaining_len;
<------>struct sk_buff *frag_iter;
<------>int frag; /* frag == -1 => frag_iter->head */
<------>unsigned int frag_offset;
<------>struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
<------>unsigned int extra_count;
<------>unsigned int slot;
};
 
static void xenvif_rx_next_skb(struct xenvif_queue *queue,
<------><------><------>       struct xenvif_pkt_state *pkt)
{
<------>struct sk_buff *skb;
<------>unsigned int gso_type;
 
<------>skb = xenvif_rx_dequeue(queue);
 
<------>queue->stats.tx_bytes += skb->len;
<------>queue->stats.tx_packets++;
 
<------>/* Reset packet state. */
<------>memset(pkt, 0, sizeof(struct xenvif_pkt_state));
 
<------>pkt->skb = skb;
<------>pkt->frag_iter = skb;
<------>pkt->remaining_len = skb->len;
<------>pkt->frag = -1;
 
<------>gso_type = xenvif_gso_type(skb);
<------>if ((1 << gso_type) & queue->vif->gso_mask) {
<------><------>struct xen_netif_extra_info *extra;
 
<------><------>extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 
<------><------>extra->u.gso.type = gso_type;
<------><------>extra->u.gso.size = skb_shinfo(skb)->gso_size;
<------><------>extra->u.gso.pad = 0;
<------><------>extra->u.gso.features = 0;
<------><------>extra->type = XEN_NETIF_EXTRA_TYPE_GSO;
<------><------>extra->flags = 0;
 
<------><------>pkt->extra_count++;
<------>}
 
<------>if (queue->vif->xdp_headroom) {
<------><------>struct xen_netif_extra_info *extra;
 
<------><------>extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_XDP - 1];
 
<------><------>memset(extra, 0, sizeof(struct xen_netif_extra_info));
<------><------>extra->u.xdp.headroom = queue->vif->xdp_headroom;
<------><------>extra->type = XEN_NETIF_EXTRA_TYPE_XDP;
<------><------>extra->flags = 0;
 
<------><------>pkt->extra_count++;
<------>}
 
<------>if (skb->sw_hash) {
<------><------>struct xen_netif_extra_info *extra;
 
<------><------>extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
 
<------><------>extra->u.hash.algorithm =
<------><------><------>XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ;
 
<------><------>if (skb->l4_hash)
<------><------><------>extra->u.hash.type =
<------><------><------><------>skb->protocol == htons(ETH_P_IP) ?
<------><------><------><------>_XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP :
<------><------><------><------>_XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
<------><------>else
<------><------><------>extra->u.hash.type =
<------><------><------><------>skb->protocol == htons(ETH_P_IP) ?
<------><------><------><------>_XEN_NETIF_CTRL_HASH_TYPE_IPV4 :
<------><------><------><------>_XEN_NETIF_CTRL_HASH_TYPE_IPV6;
 
<------><------>*(uint32_t *)extra->u.hash.value = skb_get_hash_raw(skb);
 
<------><------>extra->type = XEN_NETIF_EXTRA_TYPE_HASH;
<------><------>extra->flags = 0;
 
<------><------>pkt->extra_count++;
<------>}
}
 
static void xenvif_rx_complete(struct xenvif_queue *queue,
<------><------><------>       struct xenvif_pkt_state *pkt)
{
<------>/* All responses are ready to be pushed. */
<------>queue->rx.rsp_prod_pvt = queue->rx.req_cons;
 
<------>__skb_queue_tail(queue->rx_copy.completed, pkt->skb);
}
 
static void xenvif_rx_next_frag(struct xenvif_pkt_state *pkt)
{
<------>struct sk_buff *frag_iter = pkt->frag_iter;
<------>unsigned int nr_frags = skb_shinfo(frag_iter)->nr_frags;
 
<------>pkt->frag++;
<------>pkt->frag_offset = 0;
 
<------>if (pkt->frag >= nr_frags) {
<------><------>if (frag_iter == pkt->skb)
<------><------><------>pkt->frag_iter = skb_shinfo(frag_iter)->frag_list;
<------><------>else
<------><------><------>pkt->frag_iter = frag_iter->next;
 
<------><------>pkt->frag = -1;
<------>}
}
 
static void xenvif_rx_next_chunk(struct xenvif_queue *queue,
<------><------><------><------> struct xenvif_pkt_state *pkt,
<------><------><------><------> unsigned int offset, void **data,
<------><------><------><------> size_t *len)
{
<------>struct sk_buff *frag_iter = pkt->frag_iter;
<------>void *frag_data;
<------>size_t frag_len, chunk_len;
 
<------>BUG_ON(!frag_iter);
 
<------>if (pkt->frag == -1) {
<------><------>frag_data = frag_iter->data;
<------><------>frag_len = skb_headlen(frag_iter);
<------>} else {
<------><------>skb_frag_t *frag = &skb_shinfo(frag_iter)->frags[pkt->frag];
 
<------><------>frag_data = skb_frag_address(frag);
<------><------>frag_len = skb_frag_size(frag);
<------>}
 
<------>frag_data += pkt->frag_offset;
<------>frag_len -= pkt->frag_offset;
 
<------>chunk_len = min_t(size_t, frag_len, XEN_PAGE_SIZE - offset);
<------>chunk_len = min_t(size_t, chunk_len, XEN_PAGE_SIZE -
<------><------><------><------><------>     xen_offset_in_page(frag_data));
 
<------>pkt->frag_offset += chunk_len;
 
<------>/* Advance to next frag? */
<------>if (frag_len == chunk_len)
<------><------>xenvif_rx_next_frag(pkt);
 
<------>*data = frag_data;
<------>*len = chunk_len;
}
 
static void xenvif_rx_data_slot(struct xenvif_queue *queue,
<------><------><------><------>struct xenvif_pkt_state *pkt,
<------><------><------><------>struct xen_netif_rx_request *req,
<------><------><------><------>struct xen_netif_rx_response *rsp)
{
<------>unsigned int offset = queue->vif->xdp_headroom;
<------>unsigned int flags;
 
<------>do {
<------><------>size_t len;
<------><------>void *data;
 
<------><------>xenvif_rx_next_chunk(queue, pkt, offset, &data, &len);
<------><------>xenvif_rx_copy_add(queue, req, offset, data, len);
 
<------><------>offset += len;
<------><------>pkt->remaining_len -= len;
 
<------>} while (offset < XEN_PAGE_SIZE && pkt->remaining_len > 0);
 
<------>if (pkt->remaining_len > 0)
<------><------>flags = XEN_NETRXF_more_data;
<------>else
<------><------>flags = 0;
 
<------>if (pkt->slot == 0) {
<------><------>struct sk_buff *skb = pkt->skb;
 
<------><------>if (skb->ip_summed == CHECKSUM_PARTIAL)
<------><------><------>flags |= XEN_NETRXF_csum_blank |
<------><------><------><------> XEN_NETRXF_data_validated;
<------><------>else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
<------><------><------>flags |= XEN_NETRXF_data_validated;
 
<------><------>if (pkt->extra_count != 0)
<------><------><------>flags |= XEN_NETRXF_extra_info;
<------>}
 
<------>rsp->offset = 0;
<------>rsp->flags = flags;
<------>rsp->id = req->id;
<------>rsp->status = (s16)offset;
}
 
static void xenvif_rx_extra_slot(struct xenvif_queue *queue,
<------><------><------><------> struct xenvif_pkt_state *pkt,
<------><------><------><------> struct xen_netif_rx_request *req,
<------><------><------><------> struct xen_netif_rx_response *rsp)
{
<------>struct xen_netif_extra_info *extra = (void *)rsp;
<------>unsigned int i;
 
<------>pkt->extra_count--;
 
<------>for (i = 0; i < ARRAY_SIZE(pkt->extras); i++) {
<------><------>if (pkt->extras[i].type) {
<------><------><------>*extra = pkt->extras[i];
 
<------><------><------>if (pkt->extra_count != 0)
<------><------><------><------>extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
 
<------><------><------>pkt->extras[i].type = 0;
<------><------><------>return;
<------><------>}
<------>}
<------>BUG();
}
 
static void xenvif_rx_skb(struct xenvif_queue *queue)
{
<------>struct xenvif_pkt_state pkt;
 
<------>xenvif_rx_next_skb(queue, &pkt);
 
<------>queue->last_rx_time = jiffies;
 
<------>do {
<------><------>struct xen_netif_rx_request *req;
<------><------>struct xen_netif_rx_response *rsp;
 
<------><------>req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons);
<------><------>rsp = RING_GET_RESPONSE(&queue->rx, queue->rx.req_cons);
 
<------><------>/* Extras must go after the first data slot */
<------><------>if (pkt.slot != 0 && pkt.extra_count != 0)
<------><------><------>xenvif_rx_extra_slot(queue, &pkt, req, rsp);
<------><------>else
<------><------><------>xenvif_rx_data_slot(queue, &pkt, req, rsp);
 
<------><------>queue->rx.req_cons++;
<------><------>pkt.slot++;
<------>} while (pkt.remaining_len > 0 || pkt.extra_count != 0);
 
<------>xenvif_rx_complete(queue, &pkt);
}
 
#define RX_BATCH_SIZE 64
 
void xenvif_rx_action(struct xenvif_queue *queue)
{
<------>struct sk_buff_head completed_skbs;
<------>unsigned int work_done = 0;
 
<------>__skb_queue_head_init(&completed_skbs);
<------>queue->rx_copy.completed = &completed_skbs;
 
<------>while (xenvif_rx_ring_slots_available(queue) &&
<------>       work_done < RX_BATCH_SIZE) {
<------><------>xenvif_rx_skb(queue);
<------><------>work_done++;
<------>}
 
<------>/* Flush any pending copies and complete all skbs. */
<------>xenvif_rx_copy_flush(queue);
}
 
static RING_IDX xenvif_rx_queue_slots(const struct xenvif_queue *queue)
{
<------>RING_IDX prod, cons;
 
<------>prod = queue->rx.sring->req_prod;
<------>cons = queue->rx.req_cons;
 
<------>return prod - cons;
}
 
static bool xenvif_rx_queue_stalled(const struct xenvif_queue *queue)
{
<------>unsigned int needed = READ_ONCE(queue->rx_slots_needed);
 
<------>return !queue->stalled &&
<------><------>xenvif_rx_queue_slots(queue) < needed &&
<------><------>time_after(jiffies,
<------><------><------>   queue->last_rx_time + queue->vif->stall_timeout);
}
 
static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
{
<------>unsigned int needed = READ_ONCE(queue->rx_slots_needed);
 
<------>return queue->stalled && xenvif_rx_queue_slots(queue) >= needed;
}
 
bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread)
{
<------>return xenvif_rx_ring_slots_available(queue) ||
<------><------>(queue->vif->stall_timeout &&
<------><------> (xenvif_rx_queue_stalled(queue) ||
<------><------>  xenvif_rx_queue_ready(queue))) ||
<------><------>(test_kthread && kthread_should_stop()) ||
<------><------>queue->vif->disabled;
}
 
static long xenvif_rx_queue_timeout(struct xenvif_queue *queue)
{
<------>struct sk_buff *skb;
<------>long timeout;
 
<------>skb = skb_peek(&queue->rx_queue);
<------>if (!skb)
<------><------>return MAX_SCHEDULE_TIMEOUT;
 
<------>timeout = XENVIF_RX_CB(skb)->expires - jiffies;
<------>return timeout < 0 ? 0 : timeout;
}
 
/* Wait until the guest Rx thread has work.
 *
 * The timeout needs to be adjusted based on the current head of the
 * queue (and not just the head at the beginning).  In particular, if
 * the queue is initially empty an infinite timeout is used and this
 * needs to be reduced when a skb is queued.
 *
 * This cannot be done with wait_event_timeout() because it only
 * calculates the timeout once.
 */
static void xenvif_wait_for_rx_work(struct xenvif_queue *queue)
{
<------>DEFINE_WAIT(wait);
 
<------>if (xenvif_have_rx_work(queue, true))
<------><------>return;
 
<------>for (;;) {
<------><------>long ret;
 
<------><------>prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
<------><------>if (xenvif_have_rx_work(queue, true))
<------><------><------>break;
<------><------>if (atomic_fetch_andnot(NETBK_RX_EOI | NETBK_COMMON_EOI,
<------><------><------><------><------>&queue->eoi_pending) &
<------><------>    (NETBK_RX_EOI | NETBK_COMMON_EOI))
<------><------><------>xen_irq_lateeoi(queue->rx_irq, 0);
 
<------><------>ret = schedule_timeout(xenvif_rx_queue_timeout(queue));
<------><------>if (!ret)
<------><------><------>break;
<------>}
<------>finish_wait(&queue->wq, &wait);
}
 
static void xenvif_queue_carrier_off(struct xenvif_queue *queue)
{
<------>struct xenvif *vif = queue->vif;
 
<------>queue->stalled = true;
 
<------>/* At least one queue has stalled? Disable the carrier. */
<------>spin_lock(&vif->lock);
<------>if (vif->stalled_queues++ == 0) {
<------><------>netdev_info(vif->dev, "Guest Rx stalled");
<------><------>netif_carrier_off(vif->dev);
<------>}
<------>spin_unlock(&vif->lock);
}
 
static void xenvif_queue_carrier_on(struct xenvif_queue *queue)
{
<------>struct xenvif *vif = queue->vif;
 
<------>queue->last_rx_time = jiffies; /* Reset Rx stall detection. */
<------>queue->stalled = false;
 
<------>/* All queues are ready? Enable the carrier. */
<------>spin_lock(&vif->lock);
<------>if (--vif->stalled_queues == 0) {
<------><------>netdev_info(vif->dev, "Guest Rx ready");
<------><------>netif_carrier_on(vif->dev);
<------>}
<------>spin_unlock(&vif->lock);
}
 
int xenvif_kthread_guest_rx(void *data)
{
<------>struct xenvif_queue *queue = data;
<------>struct xenvif *vif = queue->vif;
 
<------>if (!vif->stall_timeout)
<------><------>xenvif_queue_carrier_on(queue);
 
<------>for (;;) {
<------><------>xenvif_wait_for_rx_work(queue);
 
<------><------>if (kthread_should_stop())
<------><------><------>break;
 
<------><------>/* This frontend is found to be rogue, disable it in
<------><------> * kthread context. Currently this is only set when
<------><------> * netback finds out frontend sends malformed packet,
<------><------> * but we cannot disable the interface in softirq
<------><------> * context so we defer it here, if this thread is
<------><------> * associated with queue 0.
<------><------> */
<------><------>if (unlikely(vif->disabled && queue->id == 0)) {
<------><------><------>xenvif_carrier_off(vif);
<------><------><------>break;
<------><------>}
 
<------><------>if (!skb_queue_empty(&queue->rx_queue))
<------><------><------>xenvif_rx_action(queue);
 
<------><------>/* If the guest hasn't provided any Rx slots for a
<------><------> * while it's probably not responsive, drop the
<------><------> * carrier so packets are dropped earlier.
<------><------> */
<------><------>if (vif->stall_timeout) {
<------><------><------>if (xenvif_rx_queue_stalled(queue))
<------><------><------><------>xenvif_queue_carrier_off(queue);
<------><------><------>else if (xenvif_rx_queue_ready(queue))
<------><------><------><------>xenvif_queue_carrier_on(queue);
<------><------>}
 
<------><------>/* Queued packets may have foreign pages from other
<------><------> * domains.  These cannot be queued indefinitely as
<------><------> * this would starve guests of grant refs and transmit
<------><------> * slots.
<------><------> */
<------><------>xenvif_rx_queue_drop_expired(queue);
 
<------><------>cond_resched();
<------>}
 
<------>/* Bin any remaining skbs */
<------>xenvif_rx_queue_purge(queue);
 
<------>return 0;
}