* adding 'size' bytes to a buffer which currently contains 'offset'
* bytes.
*/
-static bool start_new_rx_buffer(int offset, unsigned long size, int head)
+static bool start_new_rx_buffer(int offset, unsigned long size, int head,
+ bool full_coalesce)
{
/* simple case: we have completely filled the current buffer. */
if (offset == MAX_BUFFER_OFFSET)
* (i) this frag would fit completely in the next buffer
* and (ii) there is already some data in the current buffer
* and (iii) this is not the head buffer.
+ * and (iv) there is no need to fully utilize the buffers
*
* Where:
* - (i) stops us splitting a frag into two copies
* by (ii) but is explicitly checked because
* netfront relies on the first buffer being
* non-empty and can crash otherwise.
+ * - (iv) is needed for skbs which can use up more than MAX_SKB_FRAGS
+ * slot
*
* This means we will effectively linearise small
* frags but do not needlessly split large buffers
* own buffers as before.
*/
BUG_ON(size > MAX_BUFFER_OFFSET);
- if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head)
+ if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head &&
+ !full_coalesce)
return true;
return false;
return meta;
}
+struct xenvif_rx_cb {
+ int meta_slots_used;
+ bool full_coalesce;
+};
+
+#define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb)
+
/*
* Set up the grant operations for this fragment. If it's a flipping
* interface, we also set up the unmap request from here.
if (bytes > size)
bytes = size;
- if (start_new_rx_buffer(npo->copy_off, bytes, *head)) {
+ if (start_new_rx_buffer(npo->copy_off,
+ bytes,
+ *head,
+ XENVIF_RX_CB(skb)->full_coalesce)) {
/*
* Netfront requires there to be some data in the head
* buffer.
}
}
-struct xenvif_rx_cb {
- int meta_slots_used;
-};
-
-#define XENVIF_RX_CB(skb) ((struct xenvif_rx_cb *)(skb)->cb)
-
void xenvif_kick_thread(struct xenvif_queue *queue)
{
wake_up(&queue->wq);
/* To avoid the estimate becoming too pessimal for some
* frontends that limit posted rx requests, cap the estimate
- * at MAX_SKB_FRAGS.
+ * at MAX_SKB_FRAGS. In this case netback will fully coalesce
+ * the skb into the provided slots.
*/
- if (max_slots_needed > MAX_SKB_FRAGS)
+ if (max_slots_needed > MAX_SKB_FRAGS) {
max_slots_needed = MAX_SKB_FRAGS;
+ XENVIF_RX_CB(skb)->full_coalesce = true;
+ } else {
+ XENVIF_RX_CB(skb)->full_coalesce = false;
+ }
/* We may need one more slot for GSO metadata */
if (skb_is_gso(skb) &&
{
struct gnttab_map_grant_ref *gop_map = *gopp_map;
u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
+ /* This always points to the shinfo of the skb being checked, which
+ * could be either the first or the one on the frag_list
+ */
struct skb_shared_info *shinfo = skb_shinfo(skb);
+ /* If this is non-NULL, we are currently checking the frag_list skb, and
+ * this points to the shinfo of the first one
+ */
+ struct skb_shared_info *first_shinfo = NULL;
int nr_frags = shinfo->nr_frags;
+ const bool sharedslot = nr_frags &&
+ frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
int i, err;
- struct sk_buff *first_skb = NULL;
/* Check status of header. */
err = (*gopp_copy)->status;
- (*gopp_copy)++;
if (unlikely(err)) {
if (net_ratelimit())
netdev_dbg(queue->vif->dev,
(*gopp_copy)->status,
pending_idx,
(*gopp_copy)->source.u.ref);
- xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
+ /* The first frag might still have this slot mapped */
+ if (!sharedslot)
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_ERROR);
}
+ (*gopp_copy)++;
check_frags:
for (i = 0; i < nr_frags; i++, gop_map++) {
pending_idx,
gop_map->handle);
/* Had a previous error? Invalidate this fragment. */
- if (unlikely(err))
+ if (unlikely(err)) {
xenvif_idx_unmap(queue, pending_idx);
+ /* If the mapping of the first frag was OK, but
+ * the header's copy failed, and they are
+ * sharing a slot, send an error
+ */
+ if (i == 0 && sharedslot)
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_ERROR);
+ else
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_OKAY);
+ }
continue;
}
gop_map->status,
pending_idx,
gop_map->ref);
+
xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
/* Not the first error? Preceding frags already invalidated. */
if (err)
continue;
- /* First error: invalidate preceding fragments. */
+
+ /* First error: if the header haven't shared a slot with the
+ * first frag, release it as well.
+ */
+ if (!sharedslot)
+ xenvif_idx_release(queue,
+ XENVIF_TX_CB(skb)->pending_idx,
+ XEN_NETIF_RSP_OKAY);
+
+ /* Invalidate preceding fragments of this skb. */
for (j = 0; j < i; j++) {
pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
xenvif_idx_unmap(queue, pending_idx);
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_OKAY);
+ }
+
+ /* And if we found the error while checking the frag_list, unmap
+ * the first skb's frags
+ */
+ if (first_shinfo) {
+ for (j = 0; j < first_shinfo->nr_frags; j++) {
+ pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
+ xenvif_idx_unmap(queue, pending_idx);
+ xenvif_idx_release(queue, pending_idx,
+ XEN_NETIF_RSP_OKAY);
+ }
}
/* Remember the error: invalidate all subsequent fragments. */
err = newerr;
}
- if (skb_has_frag_list(skb)) {
- first_skb = skb;
- skb = shinfo->frag_list;
- shinfo = skb_shinfo(skb);
+ if (skb_has_frag_list(skb) && !first_shinfo) {
+ first_shinfo = skb_shinfo(skb);
+ shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
nr_frags = shinfo->nr_frags;
goto check_frags;
}
- /* There was a mapping error in the frag_list skb. We have to unmap
- * the first skb's frags
- */
- if (first_skb && err) {
- int j;
- shinfo = skb_shinfo(first_skb);
- for (j = 0; j < shinfo->nr_frags; j++) {
- pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
- xenvif_idx_unmap(queue, pending_idx);
- }
- }
-
*gopp_map = gop_map;
return err;
}
/* Check the remap error code. */
if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
+ /* If there was an error, xenvif_tx_check_gop is
+ * expected to release all the frags which were mapped,
+ * so kfree_skb shouldn't do it again
+ */
skb_shinfo(skb)->nr_frags = 0;
+ if (skb_has_frag_list(skb)) {
+ struct sk_buff *nskb =
+ skb_shinfo(skb)->frag_list;
+ skb_shinfo(nskb)->nr_frags = 0;
+ }
kfree_skb(skb);
continue;
}
tx_unmap_op.status);
BUG();
}
-
- xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_OKAY);
}
static inline int rx_work_todo(struct xenvif_queue *queue)
projects / linux.git / blobdiff