2 files changed, 15 insertions, 93 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 5a991266a394..49109afa2253 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -48,37 +48,8 @@
 typedef unsigned int pending_ring_idx_t;
 #define INVALID_PENDING_RING_IDX (~0U)
 
-/* For the head field in pending_tx_info: it is used to indicate
- * whether this tx info is the head of one or more coalesced requests.
- *
- * When head != INVALID_PENDING_RING_IDX, it means the start of a new
- * tx requests queue and the end of previous queue.
- *
- * An example sequence of head fields (I = INVALID_PENDING_RING_IDX):
- *
- * ...|0 I I I|5 I|9 I I I|...
- * -->|<-INUSE----------------
- *
- * After consuming the first slot(s) we have:
- *
- * ...|V V V V|5 I|9 I I I|...
- * -----FREE->|<-INUSE--------
- *
- * where V stands for "valid pending ring index". Any number other
- * than INVALID_PENDING_RING_IDX is OK. These entries are considered
- * free and can contain any number other than
- * INVALID_PENDING_RING_IDX. In practice we use 0.
- *
- * The in use non-INVALID_PENDING_RING_IDX (say 0, 5 and 9 in the
- * above example) number is the index into pending_tx_info and
- * mmap_pages arrays.
- */
 struct pending_tx_info {
-        struct xen_netif_tx_request req; /* coalesced tx request */
-        pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
-                                  * if it is head of one or more tx
-                                  * reqs
-                                  */
+        struct xen_netif_tx_request req; /* tx request */
         /* Callback data for released SKBs. The callback is always
          * xenvif_zerocopy_callback, desc contains the pending_idx, which is
          * also an index in pending_tx_info array. It is initialized in
@@ -148,11 +119,6 @@ struct xenvif {
         struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
         grant_handle_t grant_tx_handle[MAX_PENDING_REQS];
 
-        /* Coalescing tx requests before copying makes number of grant
-         * copy ops greater or equal to number of slots required. In
-         * worst case a tx request consumes 2 gnttab_copy.
-         */
-        struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
         struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
         struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
         /* passed to gnttab_[un]map_refs with pages under (un)mapping */
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index cb29134147d1..46a75706cb78 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -62,16 +62,6 @@ module_param(separate_tx_rx_irq, bool, 0644);
 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
 module_param(fatal_skb_slots, uint, 0444);
 
-/*
- * If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
- * one or more merged tx requests, otherwise it is the continuation of
- * previous tx request.
- */
-static inline int pending_tx_is_head(struct xenvif *vif, RING_IDX idx)
-{
-        return vif->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
-}
-
 static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
                                u8 status);
 
@@ -790,19 +780,6 @@ static int xenvif_count_requests(struct xenvif *vif,
         return slots;
 }
 
-static struct page *xenvif_alloc_page(struct xenvif *vif,
-                                      u16 pending_idx)
-{
-        struct page *page;
-
-        page = alloc_page(GFP_ATOMIC|__GFP_COLD);
-        if (!page)
-                return NULL;
-        vif->mmap_pages[pending_idx] = page;
-
-        return page;
-}
-
 
 struct xenvif_tx_cb {
         u16 pending_idx;
@@ -832,13 +809,9 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
         struct skb_shared_info *shinfo = skb_shinfo(skb);
         skb_frag_t *frags = shinfo->frags;
         u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
-        u16 head_idx = 0;
-        int slot, start;
-        struct page *page;
-        pending_ring_idx_t index, start_idx = 0;
-        uint16_t dst_offset;
+        int start;
+        pending_ring_idx_t index;
         unsigned int nr_slots;
-        struct pending_tx_info *first = NULL;
 
         /* At this point shinfo->nr_frags is in fact the number of
          * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
@@ -850,8 +823,8 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
 
         for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
              shinfo->nr_frags++, txp++, gop++) {
-                                index = pending_index(vif->pending_cons++);
-                                pending_idx = vif->pending_ring[index];
+                index = pending_index(vif->pending_cons++);
+                pending_idx = vif->pending_ring[index];
                 xenvif_tx_create_gop(vif, pending_idx, txp, gop);
                 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
         }
@@ -859,18 +832,6 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
         BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);
 
         return gop;
-err:
-        /* Unwind, freeing all pages and sending error responses. */
-        while (shinfo->nr_frags-- > start) {
-                xenvif_idx_release(vif,
-                                frag_get_pending_idx(&frags[shinfo->nr_frags]),
-                                XEN_NETIF_RSP_ERROR);
-        }
-        /* The head too, if necessary. */
-        if (start)
-                xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
-
-        return NULL;
 }
 
 static inline void xenvif_grant_handle_set(struct xenvif *vif,
@@ -910,7 +871,6 @@ static int xenvif_tx_check_gop(struct xenvif *vif,
         struct pending_tx_info *tx_info;
         int nr_frags = shinfo->nr_frags;
         int i, err, start;
-        u16 peek; /* peek into next tx request */
 
         /* Check status of header. */
         err = gop->status;
@@ -924,14 +884,12 @@ static int xenvif_tx_check_gop(struct xenvif *vif,
 
         for (i = start; i < nr_frags; i++) {
                 int j, newerr;
-                pending_ring_idx_t head;
 
                 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
                 tx_info = &vif->pending_tx_info[pending_idx];
-                head = tx_info->head;
 
                 /* Check error status: if okay then remember grant handle. */
-                        newerr = (++gop)->status;
+                newerr = (++gop)->status;
 
                 if (likely(!newerr)) {
                         xenvif_grant_handle_set(vif, pending_idx , gop->handle);
@@ -1136,7 +1094,6 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
                (skb_queue_len(&vif->tx_queue) < budget)) {
                 struct xen_netif_tx_request txreq;
                 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
-                struct page *page;
                 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
                 u16 pending_idx;
                 RING_IDX idx;
@@ -1507,18 +1464,17 @@ static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
 {
         struct pending_tx_info *pending_tx_info;
         pending_ring_idx_t index;
-        u16 peek; /* peek into next tx request */
         unsigned long flags;
 
-                pending_tx_info = &vif->pending_tx_info[pending_idx];
-                spin_lock_irqsave(&vif->response_lock, flags);
-                make_tx_response(vif, &pending_tx_info->req, status);
-                index = pending_index(vif->pending_prod);
-                vif->pending_ring[index] = pending_idx;
-                /* TX shouldn't use the index before we give it back here */
-                mb();
-                vif->pending_prod++;
-                spin_unlock_irqrestore(&vif->response_lock, flags);
+        pending_tx_info = &vif->pending_tx_info[pending_idx];
+        spin_lock_irqsave(&vif->response_lock, flags);
+        make_tx_response(vif, &pending_tx_info->req, status);
+        index = pending_index(vif->pending_prod);
+        vif->pending_ring[index] = pending_idx;
+        /* TX shouldn't use the index before we give it back here */
+        mb();
+        vif->pending_prod++;
+        spin_unlock_irqrestore(&vif->response_lock, flags);
 }