v4.19.13 snapshot.
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
new file mode 100644
index 0000000..ef58870
--- /dev/null
+++ b/drivers/net/xen-netback/rx.c
@@ -0,0 +1,631 @@
+/*
+ * 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>
+
+static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
+{
+ RING_IDX prod, cons;
+ struct sk_buff *skb;
+ int needed;
+
+ skb = skb_peek(&queue->rx_queue);
+ if (!skb)
+ return false;
+
+ needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
+ if (skb_is_gso(skb))
+ needed++;
+ if (skb->sw_hash)
+ needed++;
+
+ 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);
+
+ __skb_queue_tail(&queue->rx_queue, skb);
+
+ queue->rx_queue_len += skb->len;
+ 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));
+ }
+
+ 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) {
+ 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);
+ }
+}
+
+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 (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 = 0;
+ 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 bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
+{
+ RING_IDX prod, cons;
+
+ prod = queue->rx.sring->req_prod;
+ cons = queue->rx.req_cons;
+
+ return !queue->stalled &&
+ prod - cons < 1 &&
+ time_after(jiffies,
+ queue->last_rx_time + queue->vif->stall_timeout);
+}
+
+static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
+{
+ RING_IDX prod, cons;
+
+ prod = queue->rx.sring->req_prod;
+ cons = queue->rx.req_cons;
+
+ return queue->stalled && prod - cons >= 1;
+}
+
+static bool xenvif_have_rx_work(struct xenvif_queue *queue)
+{
+ return xenvif_rx_ring_slots_available(queue) ||
+ (queue->vif->stall_timeout &&
+ (xenvif_rx_queue_stalled(queue) ||
+ xenvif_rx_queue_ready(queue))) ||
+ 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))
+ return;
+
+ for (;;) {
+ long ret;
+
+ prepare_to_wait(&queue->wq, &wait, TASK_INTERRUPTIBLE);
+ if (xenvif_have_rx_work(queue))
+ break;
+ 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;
+}