xen-netback: support frontends without feature-rx-notify again

[cascardo/linux.git] / drivers / net / xen-netback / netback.c

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 6563f07..908e65e 100644 (file)
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -60,14 +60,12 @@ module_param(separate_tx_rx_irq, bool, 0644);
  */
 unsigned int rx_drain_timeout_msecs = 10000;
 module_param(rx_drain_timeout_msecs, uint, 0444);
-unsigned int rx_drain_timeout_jiffies;
 
 /* The length of time before the frontend is considered unresponsive
  * because it isn't providing Rx slots.
  */
-static unsigned int rx_stall_timeout_msecs = 60000;
+unsigned int rx_stall_timeout_msecs = 60000;
 module_param(rx_stall_timeout_msecs, uint, 0444);
-static unsigned int rx_stall_timeout_jiffies;
 
 unsigned int xenvif_max_queues;
 module_param_named(max_queues, xenvif_max_queues, uint, 0644);
@@ -82,6 +80,16 @@ MODULE_PARM_DESC(max_queues,
 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
 module_param(fatal_skb_slots, uint, 0444);
 
+/* The amount to copy out of the first guest Tx slot into the skb's
+ * linear area.  If the first slot has more data, it will be mapped
+ * and put into the first frag.
+ *
+ * This is sized to avoid pulling headers from the frags for most
+ * TCP/IP packets.
+ */
+#define XEN_NETBACK_TX_COPY_LEN 128
+
+
 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
                               u8 status);
 
@@ -125,13 +133,6 @@ static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
                            pending_tx_info[0]);
 }
 
-/* This is a miniumum size for the linear area to avoid lots of
- * calls to __pskb_pull_tail() as we set up checksum offsets. The
- * value 128 was chosen as it covers all IPv4 and most likely
- * IPv6 headers.
- */
-#define PKT_PROT_LEN 128
-
 static u16 frag_get_pending_idx(skb_frag_t *frag)
 {
        return (u16)frag->page_offset;
@@ -1446,9 +1447,9 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
                index = pending_index(queue->pending_cons);
                pending_idx = queue->pending_ring[index];
 
-               data_len = (txreq.size > PKT_PROT_LEN &&
+               data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
                            ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
-                       PKT_PROT_LEN : txreq.size;
+                       XEN_NETBACK_TX_COPY_LEN : txreq.size;
 
                skb = xenvif_alloc_skb(data_len);
                if (unlikely(skb == NULL)) {
@@ -1550,7 +1551,7 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s
                unsigned int len;
 
                BUG_ON(i >= MAX_SKB_FRAGS);
-               page = alloc_page(GFP_ATOMIC|__GFP_COLD);
+               page = alloc_page(GFP_ATOMIC);
                if (!page) {
                        int j;
                        skb->truesize += skb->data_len;
@@ -1653,11 +1654,6 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
                        }
                }
 
-               if (skb_is_nonlinear(skb) && skb_headlen(skb) < PKT_PROT_LEN) {
-                       int target = min_t(int, skb->len, PKT_PROT_LEN);
-                       __pskb_pull_tail(skb, target - skb_headlen(skb));
-               }
-
                skb->dev      = queue->vif->dev;
                skb->protocol = eth_type_trans(skb, skb->dev);
                skb_reset_network_header(skb);
@@ -2022,7 +2018,7 @@ static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
        return !queue->stalled
                && prod - cons < XEN_NETBK_RX_SLOTS_MAX
                && time_after(jiffies,
-                             queue->last_rx_time + rx_stall_timeout_jiffies);
+                             queue->last_rx_time + queue->vif->stall_timeout);
 }
 
 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
@@ -2040,8 +2036,9 @@ static bool xenvif_have_rx_work(struct xenvif_queue *queue)
 {
        return (!skb_queue_empty(&queue->rx_queue)
                && xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
-               || xenvif_rx_queue_stalled(queue)
-               || xenvif_rx_queue_ready(queue)
+               || (queue->vif->stall_timeout &&
+                   (xenvif_rx_queue_stalled(queue)
+                    || xenvif_rx_queue_ready(queue)))
                || kthread_should_stop()
                || queue->vif->disabled;
 }
@@ -2094,6 +2091,9 @@ 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);
 
@@ -2120,10 +2120,12 @@ int xenvif_kthread_guest_rx(void *data)
                 * while it's probably not responsive, drop the
                 * carrier so packets are dropped earlier.
                 */
-               if (xenvif_rx_queue_stalled(queue))
-                       xenvif_queue_carrier_off(queue);
-               else if (xenvif_rx_queue_ready(queue))
-                       xenvif_queue_carrier_on(queue);
+               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
@@ -2194,9 +2196,6 @@ static int __init netback_init(void)
        if (rc)
                goto failed_init;
 
-       rx_drain_timeout_jiffies = msecs_to_jiffies(rx_drain_timeout_msecs);
-       rx_stall_timeout_jiffies = msecs_to_jiffies(rx_stall_timeout_msecs);
-
 #ifdef CONFIG_DEBUG_FS
        xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
        if (IS_ERR_OR_NULL(xen_netback_dbg_root))