}
}
-/*
- * Returns true if we should start a new receive buffer instead of
- * adding 'size' bytes to a buffer which currently contains 'offset'
- * bytes.
- */
-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)
- return true;
-
- /*
- * complex case: start a fresh buffer if the current frag
- * would overflow the current buffer but only if:
- * (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
- * unless the frag is too large for a single buffer.
- * - (ii) stops us from leaving a buffer pointlessly empty.
- * - (iii) stops us leaving the first buffer
- * empty. Strictly speaking this is already covered
- * 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
- * into multiple copies tend to give large frags their
- * own buffers as before.
- */
- BUG_ON(size > MAX_BUFFER_OFFSET);
- if ((offset + size > MAX_BUFFER_OFFSET) && offset && !head &&
- !full_coalesce)
- return true;
-
- return false;
-}
-
struct netrx_pending_operations {
unsigned copy_prod, copy_cons;
unsigned meta_prod, meta_cons;
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 xenvif_queue *foreign_queue,
- grant_ref_t foreign_gref)
+ unsigned long offset, int *head)
{
struct gnttab_copy *copy_gop;
struct xenvif_rx_meta *meta;
offset &= ~PAGE_MASK;
while (size > 0) {
+ struct xen_page_foreign *foreign;
+
BUG_ON(offset >= PAGE_SIZE);
BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
- bytes = PAGE_SIZE - offset;
+ if (npo->copy_off == MAX_BUFFER_OFFSET)
+ meta = get_next_rx_buffer(queue, npo);
+ bytes = PAGE_SIZE - offset;
if (bytes > size)
bytes = size;
- 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.
- */
- BUG_ON(*head);
-
- meta = get_next_rx_buffer(queue, npo);
- }
-
if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
bytes = MAX_BUFFER_OFFSET - npo->copy_off;
copy_gop->flags = GNTCOPY_dest_gref;
copy_gop->len = bytes;
- if (foreign_queue) {
- copy_gop->source.domid = foreign_queue->vif->domid;
- copy_gop->source.u.ref = foreign_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;
} else {
copy_gop->source.domid = DOMID_SELF;
}
}
-/*
- * Find the grant ref for a given frag in a chain of struct ubuf_info's
- * skb: the skb itself
- * i: the frag's number
- * ubuf: a pointer to an element in the chain. It should not be NULL
- *
- * Returns a pointer to the element in the chain where the page were found. If
- * not found, returns NULL.
- * See the definition of callback_struct in common.h for more details about
- * the chain.
- */
-static const struct ubuf_info *xenvif_find_gref(const struct sk_buff *const skb,
- const int i,
- const struct ubuf_info *ubuf)
-{
- struct xenvif_queue *foreign_queue = ubuf_to_queue(ubuf);
-
- do {
- u16 pending_idx = ubuf->desc;
-
- if (skb_shinfo(skb)->frags[i].page.p ==
- foreign_queue->mmap_pages[pending_idx])
- break;
- ubuf = (struct ubuf_info *) ubuf->ctx;
- } while (ubuf);
-
- return ubuf;
-}
-
/*
* Prepare an SKB to be transmitted to the frontend.
*
int head = 1;
int old_meta_prod;
int gso_type;
- const struct ubuf_info *ubuf = skb_shinfo(skb)->destructor_arg;
- const struct ubuf_info *const head_ubuf = ubuf;
old_meta_prod = npo->meta_prod;
len = skb_tail_pointer(skb) - data;
xenvif_gop_frag_copy(queue, skb, npo,
- virt_to_page(data), len, offset, &head,
- NULL,
- 0);
+ virt_to_page(data), len, offset, &head);
data += len;
}
for (i = 0; i < nr_frags; i++) {
- /* This variable also signals whether foreign_gref has a real
- * value or not.
- */
- struct xenvif_queue *foreign_queue = NULL;
- grant_ref_t foreign_gref;
-
- if ((skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) &&
- (ubuf->callback == &xenvif_zerocopy_callback)) {
- const struct ubuf_info *const startpoint = ubuf;
-
- /* Ideally ubuf points to the chain element which
- * belongs to this frag. Or if frags were removed from
- * the beginning, then shortly before it.
- */
- ubuf = xenvif_find_gref(skb, i, ubuf);
-
- /* Try again from the beginning of the list, if we
- * haven't tried from there. This only makes sense in
- * the unlikely event of reordering the original frags.
- * For injected local pages it's an unnecessary second
- * run.
- */
- if (unlikely(!ubuf) && startpoint != head_ubuf)
- ubuf = xenvif_find_gref(skb, i, head_ubuf);
-
- if (likely(ubuf)) {
- u16 pending_idx = ubuf->desc;
-
- foreign_queue = ubuf_to_queue(ubuf);
- foreign_gref =
- foreign_queue->pending_tx_info[pending_idx].req.gref;
- /* Just a safety measure. If this was the last
- * element on the list, the for loop will
- * iterate again if a local page were added to
- * the end. Using head_ubuf here prevents the
- * second search on the chain. Or the original
- * frags changed order, but that's less likely.
- * In any way, ubuf shouldn't be NULL.
- */
- ubuf = ubuf->ctx ?
- (struct ubuf_info *) ubuf->ctx :
- head_ubuf;
- } else
- /* This frag was a local page, added to the
- * array after the skb left netback.
- */
- ubuf = head_ubuf;
- }
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,
- foreign_queue,
- foreign_queue ? foreign_gref : UINT_MAX);
+ &head);
}
return npo->meta_prod - old_meta_prod;
while (xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)
&& (skb = xenvif_rx_dequeue(queue)) != NULL) {
- RING_IDX max_slots_needed;
RING_IDX old_req_cons;
RING_IDX ring_slots_used;
- int i;
queue->last_rx_time = jiffies;
- /* We need a cheap worse case estimate for the number of
- * slots we'll use.
- */
-
- max_slots_needed = DIV_ROUND_UP(offset_in_page(skb->data) +
- skb_headlen(skb),
- PAGE_SIZE);
- for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
- unsigned int size;
- unsigned int offset;
-
- size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
- offset = skb_shinfo(skb)->frags[i].page_offset;
-
- /* For a worse-case estimate we need to factor in
- * the fragment page offset as this will affect the
- * number of times xenvif_gop_frag_copy() will
- * call start_new_rx_buffer().
- */
- max_slots_needed += DIV_ROUND_UP(offset + size,
- PAGE_SIZE);
- }
-
- /* To avoid the estimate becoming too pessimal for some
- * frontends that limit posted rx requests, cap the estimate
- * at MAX_SKB_FRAGS. In this case netback will fully coalesce
- * the skb into the provided slots.
- */
- 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) &&
- (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4 ||
- skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6))
- max_slots_needed++;
-
old_req_cons = queue->rx.req_cons;
XENVIF_RX_CB(skb)->meta_slots_used = xenvif_gop_skb(skb, &npo, queue);
ring_slots_used = queue->rx.req_cons - old_req_cons;
- BUG_ON(ring_slots_used > max_slots_needed);
-
__skb_queue_tail(&rxq, skb);
}
/* Take an extra reference to offset network stack's put_page */
get_page(queue->mmap_pages[pending_idx]);
}
- /* FIXME: __skb_fill_page_desc set this to true because page->pfmemalloc
- * overlaps with "index", and "mapping" is not set. I think mapping
- * should be set. If delivered to local stack, it would drop this
- * skb in sk_filter unless the socket has the right to use it.
- */
- skb->pfmemalloc = false;
}
static int xenvif_get_extras(struct xenvif_queue *queue,
projects / cascardo / linux.git / blobdiff