[Xen-devel] [PATCH net-next RFC 3/5] xen-netback: Remove old TX grant copy definitons

[Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>]

These became obsolate with grant mapping.

Signed-off-by: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>
---
 drivers/net/xen-netback/common.h  |   37 +---------------------------
 drivers/net/xen-netback/netback.c |   48 ++-----------------------------------
 2 files changed, 3 insertions(+), 82 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 36a3fda..e82c82c 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -46,39 +46,9 @@
 #include <xen/xenbus.h>
 
 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, ctx points to the next fragment, desc
         * contains the pending_idx
@@ -128,11 +98,6 @@ 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_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
        struct gnttab_map_grant_ref tx_map_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 e544e9f..c91dd36 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -70,16 +70,6 @@ module_param(fatal_skb_slots, uint, 0444);
  */
 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
 
-/*
- * 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);
 
@@ -856,19 +846,6 @@ 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;
-}
-
 static inline void xenvif_tx_create_gop(struct xenvif *vif, u16 pending_idx,
               struct xen_netif_tx_request *txp,
               struct gnttab_map_grant_ref *gop)
@@ -891,13 +868,9 @@ 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 = *((u16 *)skb->data);
-       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.
@@ -918,18 +891,6 @@ 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 int xenvif_tx_check_gop(struct xenvif *vif,
@@ -942,7 +903,6 @@ 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;
@@ -964,11 +924,9 @@ 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;
@@ -1396,7 +1354,6 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif)
                < MAX_PENDING_REQS)) {
                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;
@@ -1759,7 +1716,6 @@ 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 */
 
                pending_tx_info = &vif->pending_tx_info[pending_idx];
                make_tx_response(vif, &pending_tx_info->req, status);

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