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[Xen-devel] [PATCH net-next 3/7] xen-netback: refactor guest rx



From: David Vrabel <david.vrabel@xxxxxxxxxx>

Refactor the to-guest (rx) path to:

1. Push responses for completed skbs earlier, reducing latency.

2. Reduce the per-queue memory overhead by greatly reducing the
   maximum number of grant copy ops in each hypercall (from 4352 to
   64).  Each struct xenvif_queue is now only 44 kB instead of 220 kB.

3. Make the code more maintainable.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
[re-based]
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 drivers/net/xen-netback/common.h |  23 +-
 drivers/net/xen-netback/rx.c     | 654 +++++++++++++++------------------------
 2 files changed, 254 insertions(+), 423 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index e16004a..adef482 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -91,13 +91,6 @@ struct xenvif_rx_meta {
  */
 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
 
-/* It's possible for an skb to have a maximal number of frags
- * but still be less than MAX_BUFFER_OFFSET in size. Thus the
- * worst-case number of copy operations is MAX_XEN_SKB_FRAGS per
- * ring slot.
- */
-#define MAX_GRANT_COPY_OPS (MAX_XEN_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
-
 #define NETBACK_INVALID_HANDLE -1
 
 /* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
@@ -133,6 +126,14 @@ struct xenvif_stats {
        unsigned long tx_frag_overflow;
 };
 
+#define COPY_BATCH_SIZE 64
+
+struct xenvif_copy_state {
+       struct gnttab_copy op[COPY_BATCH_SIZE];
+       RING_IDX idx[COPY_BATCH_SIZE];
+       unsigned int num;
+};
+
 struct xenvif_queue { /* Per-queue data for xenvif */
        unsigned int id; /* Queue ID, 0-based */
        char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
@@ -189,12 +190,7 @@ struct xenvif_queue { /* Per-queue data for xenvif */
        unsigned long last_rx_time;
        bool stalled;
 
-       struct gnttab_copy grant_copy_op[MAX_GRANT_COPY_OPS];
-
-       /* We create one meta structure per ring request we consume, so
-        * the maximum number is the same as the ring size.
-        */
-       struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
+       struct xenvif_copy_state rx_copy;
 
        /* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
        unsigned long   credit_bytes;
@@ -360,6 +356,7 @@ int xenvif_dealloc_kthread(void *data);
 
 int xenvif_ctrl_kthread(void *data);
 
+void xenvif_rx_action(struct xenvif_queue *queue);
 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
 
 void xenvif_carrier_on(struct xenvif *vif);
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index 6bd7d6e..b0ce4c6 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -26,7 +26,6 @@
  * 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>
@@ -137,464 +136,299 @@ static void xenvif_rx_queue_drop_expired(struct 
xenvif_queue *queue)
        }
 }
 
-struct netrx_pending_operations {
-       unsigned int copy_prod, copy_cons;
-       unsigned int meta_prod, meta_cons;
-       struct gnttab_copy *copy;
-       struct xenvif_rx_meta *meta;
-       int copy_off;
-       grant_ref_t copy_gref;
-};
-
-static struct xenvif_rx_meta *get_next_rx_buffer(
-       struct xenvif_queue *queue,
-       struct netrx_pending_operations *npo)
+static void xenvif_rx_copy_flush(struct xenvif_queue *queue)
 {
-       struct xenvif_rx_meta *meta;
-       struct xen_netif_rx_request req;
+       unsigned int i;
 
-       RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
+       gnttab_batch_copy(queue->rx_copy.op, queue->rx_copy.num);
 
-       meta = npo->meta + npo->meta_prod++;
-       meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
-       meta->gso_size = 0;
-       meta->size = 0;
-       meta->id = req.id;
+       for (i = 0; i < queue->rx_copy.num; i++) {
+               struct gnttab_copy *op;
 
-       npo->copy_off = 0;
-       npo->copy_gref = req.gref;
+               op = &queue->rx_copy.op[i];
 
-       return meta;
+               /* 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;
 }
 
-struct gop_frag_copy {
-       struct xenvif_queue *queue;
-       struct netrx_pending_operations *npo;
-       struct xenvif_rx_meta *meta;
-       int head;
-       int gso_type;
-       int protocol;
-       int hash_present;
-
-       struct page *page;
-};
-
-static void xenvif_setup_copy_gop(unsigned long gfn,
-                                 unsigned int offset,
-                                 unsigned int *len,
-                                 struct gop_frag_copy *info)
+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 *copy_gop;
+       struct gnttab_copy *op;
+       struct page *page;
        struct xen_page_foreign *foreign;
-       /* Convenient aliases */
-       struct xenvif_queue *queue = info->queue;
-       struct netrx_pending_operations *npo = info->npo;
-       struct page *page = info->page;
 
-       WARN_ON(npo->copy_off > MAX_BUFFER_OFFSET);
+       if (queue->rx_copy.num == COPY_BATCH_SIZE)
+               xenvif_rx_copy_flush(queue);
 
-       if (npo->copy_off == MAX_BUFFER_OFFSET)
-               info->meta = get_next_rx_buffer(queue, npo);
+       op = &queue->rx_copy.op[queue->rx_copy.num];
 
-       if (npo->copy_off + *len > MAX_BUFFER_OFFSET)
-               *len = MAX_BUFFER_OFFSET - npo->copy_off;
+       page = virt_to_page(data);
 
-       copy_gop = npo->copy + npo->copy_prod++;
-       copy_gop->flags = GNTCOPY_dest_gref;
-       copy_gop->len = *len;
+       op->flags = GNTCOPY_dest_gref;
 
        foreign = xen_page_foreign(page);
        if (foreign) {
-               copy_gop->source.domid = foreign->domid;
-               copy_gop->source.u.ref = foreign->gref;
-               copy_gop->flags |= GNTCOPY_source_gref;
+               op->source.domid = foreign->domid;
+               op->source.u.ref = foreign->gref;
+               op->flags |= GNTCOPY_source_gref;
        } else {
-               copy_gop->source.domid = DOMID_SELF;
-               copy_gop->source.u.gmfn = gfn;
+               op->source.u.gmfn = virt_to_gfn(data);
+               op->source.domid  = DOMID_SELF;
        }
-       copy_gop->source.offset = offset;
 
-       copy_gop->dest.domid = queue->vif->domid;
-       copy_gop->dest.offset = npo->copy_off;
-       copy_gop->dest.u.ref = npo->copy_gref;
+       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;
 
-       npo->copy_off += *len;
-       info->meta->size += *len;
-
-       if (!info->head)
-               return;
-
-       /* Leave a gap for the GSO descriptor. */
-       if ((1 << info->gso_type) & queue->vif->gso_mask)
-               queue->rx.req_cons++;
-
-       /* Leave a gap for the hash extra segment. */
-       if (info->hash_present)
-               queue->rx.req_cons++;
-
-       info->head = 0; /* There must be something in this buffer now */
+       queue->rx_copy.idx[queue->rx_copy.num] = queue->rx.req_cons;
+       queue->rx_copy.num++;
 }
 
-static void xenvif_gop_frag_copy_grant(unsigned long gfn,
-                                      unsigned int offset,
-                                      unsigned int len,
-                                      void *data)
+static unsigned int xenvif_gso_type(struct sk_buff *skb)
 {
-       unsigned int bytes;
-
-       while (len) {
-               bytes = len;
-               xenvif_setup_copy_gop(gfn, offset, &bytes, data);
-               offset += bytes;
-               len -= bytes;
-       }
-}
-
-/* Set up the grant operations for this fragment. If it's a flipping
- * interface, we also set up the unmap request from here.
- */
-static void xenvif_gop_frag_copy(struct xenvif_queue *queue,
-                                struct sk_buff *skb,
-                                struct netrx_pending_operations *npo,
-                                struct page *page, unsigned long size,
-                                unsigned long offset, int *head)
-{
-       struct gop_frag_copy info = {
-               .queue = queue,
-               .npo = npo,
-               .head = *head,
-               .gso_type = XEN_NETIF_GSO_TYPE_NONE,
-               /* xenvif_set_skb_hash() will have either set a s/w
-                * hash or cleared the hash depending on
-                * whether the the frontend wants a hash for this skb.
-                */
-               .hash_present = skb->sw_hash,
-       };
-       unsigned long bytes;
-
        if (skb_is_gso(skb)) {
                if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
-                       info.gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
-               else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
-                       info.gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
-       }
-
-       /* Data must not cross a page boundary. */
-       WARN_ON(size + offset > (PAGE_SIZE << compound_order(page)));
-
-       info.meta = npo->meta + npo->meta_prod - 1;
-
-       /* Skip unused frames from start of page */
-       page += offset >> PAGE_SHIFT;
-       offset &= ~PAGE_MASK;
-
-       while (size > 0) {
-               WARN_ON(offset >= PAGE_SIZE);
-
-               bytes = PAGE_SIZE - offset;
-               if (bytes > size)
-                       bytes = size;
-
-               info.page = page;
-               gnttab_foreach_grant_in_range(page, offset, bytes,
-                                             xenvif_gop_frag_copy_grant,
-                                             &info);
-               size -= bytes;
-               offset = 0;
-
-               /* Next page */
-               if (size) {
-                       WARN_ON(!PageCompound(page));
-                       page++;
-               }
-       }
-
-       *head = info.head;
-}
-
-/* Prepare an SKB to be transmitted to the frontend.
- *
- * This function is responsible for allocating grant operations, meta
- * structures, etc.
- *
- * It returns the number of meta structures consumed. The number of
- * ring slots used is always equal to the number of meta slots used
- * plus the number of GSO descriptors used. Currently, we use either
- * zero GSO descriptors (for non-GSO packets) or one descriptor (for
- * frontend-side LRO).
- */
-static int xenvif_gop_skb(struct sk_buff *skb,
-                         struct netrx_pending_operations *npo,
-                         struct xenvif_queue *queue)
-{
-       struct xenvif *vif = netdev_priv(skb->dev);
-       int nr_frags = skb_shinfo(skb)->nr_frags;
-       int i;
-       struct xen_netif_rx_request req;
-       struct xenvif_rx_meta *meta;
-       unsigned char *data;
-       int head = 1;
-       int old_meta_prod;
-       int gso_type;
-
-       old_meta_prod = npo->meta_prod;
-
-       gso_type = XEN_NETIF_GSO_TYPE_NONE;
-       if (skb_is_gso(skb)) {
-               if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
-                       gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
-               else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
-                       gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
-       }
-
-       RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
-       meta = npo->meta + npo->meta_prod++;
-
-       if ((1 << gso_type) & vif->gso_mask) {
-               meta->gso_type = gso_type;
-               meta->gso_size = skb_shinfo(skb)->gso_size;
-       } else {
-               meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
-               meta->gso_size = 0;
-       }
-
-       meta->size = 0;
-       meta->id = req.id;
-       npo->copy_off = 0;
-       npo->copy_gref = req.gref;
-
-       data = skb->data;
-       while (data < skb_tail_pointer(skb)) {
-               unsigned int offset = offset_in_page(data);
-               unsigned int len = PAGE_SIZE - offset;
-
-               if (data + len > skb_tail_pointer(skb))
-                       len = skb_tail_pointer(skb) - data;
-
-               xenvif_gop_frag_copy(queue, skb, npo,
-                                    virt_to_page(data), len, offset, &head);
-               data += len;
-       }
-
-       for (i = 0; i < nr_frags; i++) {
-               xenvif_gop_frag_copy(queue, skb, npo,
-                                    skb_frag_page(&skb_shinfo(skb)->frags[i]),
-                                    skb_frag_size(&skb_shinfo(skb)->frags[i]),
-                                    skb_shinfo(skb)->frags[i].page_offset,
-                                    &head);
-       }
-
-       return npo->meta_prod - old_meta_prod;
-}
-
-/* This is a twin to xenvif_gop_skb.  Assume that xenvif_gop_skb was
- * used to set up the operations on the top of
- * netrx_pending_operations, which have since been done.  Check that
- * they didn't give any errors and advance over them.
- */
-static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
-                           struct netrx_pending_operations *npo)
-{
-       struct gnttab_copy     *copy_op;
-       int status = XEN_NETIF_RSP_OKAY;
-       int i;
-
-       for (i = 0; i < nr_meta_slots; i++) {
-               copy_op = npo->copy + npo->copy_cons++;
-               if (copy_op->status != GNTST_okay) {
-                       netdev_dbg(vif->dev,
-                                  "Bad status %d from copy to DOM%d.\n",
-                                  copy_op->status, vif->domid);
-                       status = XEN_NETIF_RSP_ERROR;
-               }
-       }
-
-       return status;
-}
-
-static struct xen_netif_rx_response *make_rx_response(
-       struct xenvif_queue *queue, u16 id, s8 st, u16 offset, u16 size,
-       u16 flags)
-{
-       RING_IDX i = queue->rx.rsp_prod_pvt;
-       struct xen_netif_rx_response *resp;
-
-       resp = RING_GET_RESPONSE(&queue->rx, i);
-       resp->offset     = offset;
-       resp->flags      = flags;
-       resp->id         = id;
-       resp->status     = (s16)size;
-       if (st < 0)
-               resp->status = (s16)st;
-
-       queue->rx.rsp_prod_pvt = ++i;
-
-       return resp;
-}
-
-static void xenvif_add_frag_responses(struct xenvif_queue *queue,
-                                     int status,
-                                     struct xenvif_rx_meta *meta,
-                                     int nr_meta_slots)
-{
-       int i;
-       unsigned long offset;
-
-       /* No fragments used */
-       if (nr_meta_slots <= 1)
-               return;
-
-       nr_meta_slots--;
-
-       for (i = 0; i < nr_meta_slots; i++) {
-               int flags;
-
-               if (i == nr_meta_slots - 1)
-                       flags = 0;
+                       return XEN_NETIF_GSO_TYPE_TCPV4;
                else
-                       flags = XEN_NETRXF_more_data;
-
-               offset = 0;
-               make_rx_response(queue, meta[i].id, status, offset,
-                                meta[i].size, flags);
+                       return XEN_NETIF_GSO_TYPE_TCPV6;
        }
+       return XEN_NETIF_GSO_TYPE_NONE;
 }
 
-static void xenvif_rx_action(struct xenvif_queue *queue)
-{
-       struct xenvif *vif = queue->vif;
-       s8 status;
-       u16 flags;
-       struct xen_netif_rx_response *resp;
-       struct sk_buff_head rxq;
+struct xenvif_pkt_state {
        struct sk_buff *skb;
-       LIST_HEAD(notify);
-       int ret;
-       unsigned long offset;
-       bool need_to_notify = false;
+       size_t remaining_len;
+       int frag; /* frag == -1 => skb->head */
+       unsigned int frag_offset;
+       struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
+       unsigned int extra_count;
+       unsigned int slot;
+};
 
-       struct netrx_pending_operations npo = {
-               .copy  = queue->grant_copy_op,
-               .meta  = queue->meta,
-       };
+static void xenvif_rx_next_skb(struct xenvif_queue *queue,
+                              struct xenvif_pkt_state *pkt)
+{
+       struct sk_buff *skb;
+       unsigned int gso_type;
 
-       skb_queue_head_init(&rxq);
+       skb = xenvif_rx_dequeue(queue);
 
-       while (xenvif_rx_ring_slots_available(queue) &&
-              (skb = xenvif_rx_dequeue(queue)) != NULL) {
-               queue->last_rx_time = jiffies;
+       queue->stats.tx_bytes += skb->len;
+       queue->stats.tx_packets++;
 
-               XENVIF_RX_CB(skb)->meta_slots_used =
-                       xenvif_gop_skb(skb, &npo, queue);
+       /* Reset packet state. */
+       memset(pkt, 0, sizeof(struct xenvif_pkt_state));
 
-               __skb_queue_tail(&rxq, skb);
+       pkt->skb = 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++;
        }
 
-       WARN_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
+       if (skb->sw_hash) {
+               struct xen_netif_extra_info *extra;
 
-       if (!npo.copy_prod)
-               goto done;
+               extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
 
-       WARN_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
-       gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
+               extra->u.hash.algorithm =
+                       XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ;
 
-       while ((skb = __skb_dequeue(&rxq)) != NULL) {
-               struct xen_netif_extra_info *extra = NULL;
-
-               queue->stats.tx_bytes += skb->len;
-               queue->stats.tx_packets++;
-
-               status = xenvif_check_gop(vif,
-                                         XENVIF_RX_CB(skb)->meta_slots_used,
-                                         &npo);
-
-               if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
-                       flags = 0;
+               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
-                       flags = XEN_NETRXF_more_data;
+                       extra->u.hash.type =
+                               skb->protocol == htons(ETH_P_IP) ?
+                               _XEN_NETIF_CTRL_HASH_TYPE_IPV4 :
+                               _XEN_NETIF_CTRL_HASH_TYPE_IPV6;
 
-               if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
+               *(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)
+{
+       int notify;
+
+       /* Complete any outstanding copy ops for this skb. */
+       xenvif_rx_copy_flush(queue);
+
+       /* Push responses and notify. */
+       queue->rx.rsp_prod_pvt = queue->rx.req_cons;
+       RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, notify);
+       if (notify)
+               notify_remote_via_irq(queue->rx_irq);
+
+       dev_kfree_skb(pkt->skb);
+}
+
+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 *skb = pkt->skb;
+       void *frag_data;
+       size_t frag_len, chunk_len;
+
+       if (pkt->frag == -1) {
+               frag_data = skb->data;
+               frag_len = skb_headlen(skb);
+       } else {
+               skb_frag_t *frag = &skb_shinfo(skb)->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(frag_len, XEN_PAGE_SIZE - offset);
+       chunk_len = min(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) {
+               pkt->frag++;
+               pkt->frag_offset = 0;
+       }
+
+       *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)
-                       /* remote but checksummed. */
                        flags |= XEN_NETRXF_data_validated;
 
-               offset = 0;
-               resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
-                                       status, offset,
-                                       queue->meta[npo.meta_cons].size,
-                                       flags);
-
-               if ((1 << queue->meta[npo.meta_cons].gso_type) &
-                   vif->gso_mask) {
-                       extra = (struct xen_netif_extra_info *)
-                               RING_GET_RESPONSE(&queue->rx,
-                                                 queue->rx.rsp_prod_pvt++);
-
-                       resp->flags |= XEN_NETRXF_extra_info;
-
-                       extra->u.gso.type = queue->meta[npo.meta_cons].gso_type;
-                       extra->u.gso.size = queue->meta[npo.meta_cons].gso_size;
-                       extra->u.gso.pad = 0;
-                       extra->u.gso.features = 0;
-
-                       extra->type = XEN_NETIF_EXTRA_TYPE_GSO;
-                       extra->flags = 0;
-               }
-
-               if (skb->sw_hash) {
-                       /* Since the skb got here via xenvif_select_queue()
-                        * we know that the hash has been re-calculated
-                        * according to a configuration set by the frontend
-                        * and therefore we know that it is legitimate to
-                        * pass it to the frontend.
-                        */
-                       if (resp->flags & XEN_NETRXF_extra_info)
-                               extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
-                       else
-                               resp->flags |= XEN_NETRXF_extra_info;
-
-                       extra = (struct xen_netif_extra_info *)
-                               RING_GET_RESPONSE(&queue->rx,
-                                                 queue->rx.rsp_prod_pvt++);
-
-                       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;
-               }
-
-               xenvif_add_frag_responses(queue, status,
-                                         queue->meta + npo.meta_cons + 1,
-                                         XENVIF_RX_CB(skb)->meta_slots_used);
-
-               RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
-
-               need_to_notify |= !!ret;
-
-               npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
-               dev_kfree_skb(skb);
+               if (pkt->extra_count != 0)
+                       flags |= XEN_NETRXF_extra_info;
        }
 
-done:
-       if (need_to_notify)
-               notify_remote_via_irq(queue->rx_irq);
+       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();
+}
+
+void xenvif_rx_action(struct xenvif_queue *queue)
+{
+       struct xenvif_pkt_state pkt;
+
+       xenvif_rx_next_skb(queue, &pkt);
+
+       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);
 }
 
 static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
-- 
2.1.4


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