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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 3/3] xen-netfront: refactor making Tx requests
Eliminate all the duplicate code for making Tx requests by
consolidating them into a single xennet_make_one_txreq() function.
xennet_make_one_txreq() and xennet_make_txreqs() work with pages and
offsets so it will be easier to make netfront handle highmem frags in
the future.
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
drivers/net/xen-netfront.c | 181 ++++++++++++++++----------------------------
1 file changed, 67 insertions(+), 114 deletions(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 6b29b3a..68e0e8f 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -425,99 +425,56 @@ static void xennet_tx_buf_gc(struct netfront_queue *queue)
xennet_maybe_wake_tx(queue);
}
-static void xennet_make_frags(struct sk_buff *skb, struct netfront_queue
*queue,
- struct xen_netif_tx_request *tx)
-{
- char *data = skb->data;
- unsigned long mfn;
- RING_IDX prod = queue->tx.req_prod_pvt;
- int frags = skb_shinfo(skb)->nr_frags;
- unsigned int offset = offset_in_page(data);
- unsigned int len = skb_headlen(skb);
+static struct xen_netif_tx_request *xennet_make_one_txreq(
+ struct netfront_queue *queue, struct sk_buff *skb,
+ struct page *page, unsigned int offset, unsigned int len)
+{
unsigned int id;
+ struct xen_netif_tx_request *tx;
grant_ref_t ref;
- int i;
- /* While the header overlaps a page boundary (including being
- larger than a page), split it it into page-sized chunks. */
- while (len > PAGE_SIZE - offset) {
- tx->size = PAGE_SIZE - offset;
- tx->flags |= XEN_NETTXF_more_data;
- len -= tx->size;
- data += tx->size;
- offset = 0;
+ len = min_t(unsigned int, PAGE_SIZE - offset, len);
- id = get_id_from_freelist(&queue->tx_skb_freelist,
queue->tx_skbs);
- queue->tx_skbs[id].skb = skb_get(skb);
- tx = RING_GET_REQUEST(&queue->tx, prod++);
- tx->id = id;
- ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
- BUG_ON((signed short)ref < 0);
+ id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
+ tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
+ ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
+ BUG_ON((signed short)ref < 0);
- mfn = virt_to_mfn(data);
- gnttab_grant_foreign_access_ref(ref,
queue->info->xbdev->otherend_id,
- mfn, GNTMAP_readonly);
+ gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
+ page_to_mfn(page), GNTMAP_readonly);
- queue->grant_tx_page[id] = virt_to_page(data);
- tx->gref = queue->grant_tx_ref[id] = ref;
- tx->offset = offset;
- tx->size = len;
- tx->flags = 0;
- }
+ queue->tx_skbs[id].skb = skb;
+ queue->grant_tx_page[id] = page;
+ queue->grant_tx_ref[id] = ref;
- /* Grant backend access to each skb fragment page. */
- for (i = 0; i < frags; i++) {
- skb_frag_t *frag = skb_shinfo(skb)->frags + i;
- struct page *page = skb_frag_page(frag);
+ tx->id = id;
+ tx->gref = ref;
+ tx->offset = offset;
+ tx->size = len;
+ tx->flags = 0;
- len = skb_frag_size(frag);
- offset = frag->page_offset;
+ return tx;
+}
- /* Skip unused frames from start of page */
- page += offset >> PAGE_SHIFT;
- offset &= ~PAGE_MASK;
+static struct xen_netif_tx_request *xennet_make_txreqs(
+ struct netfront_queue *queue, struct xen_netif_tx_request *tx,
+ struct sk_buff *skb, struct page *page,
+ unsigned int offset, unsigned int len)
+{
+ /* Skip unused frames from start of page */
+ page += offset >> PAGE_SHIFT;
+ offset &= ~PAGE_MASK;
- while (len > 0) {
- unsigned long bytes;
-
- bytes = PAGE_SIZE - offset;
- if (bytes > len)
- bytes = len;
-
- tx->flags |= XEN_NETTXF_more_data;
-
- id = get_id_from_freelist(&queue->tx_skb_freelist,
- queue->tx_skbs);
- queue->tx_skbs[id].skb = skb_get(skb);
- tx = RING_GET_REQUEST(&queue->tx, prod++);
- tx->id = id;
- ref =
gnttab_claim_grant_reference(&queue->gref_tx_head);
- BUG_ON((signed short)ref < 0);
-
- mfn = pfn_to_mfn(page_to_pfn(page));
- gnttab_grant_foreign_access_ref(ref,
-
queue->info->xbdev->otherend_id,
- mfn, GNTMAP_readonly);
-
- queue->grant_tx_page[id] = page;
- tx->gref = queue->grant_tx_ref[id] = ref;
- tx->offset = offset;
- tx->size = bytes;
- tx->flags = 0;
-
- offset += bytes;
- len -= bytes;
-
- /* Next frame */
- if (offset == PAGE_SIZE && len) {
- BUG_ON(!PageCompound(page));
- page++;
- offset = 0;
- }
- }
+ while (len) {
+ tx->flags |= XEN_NETTXF_more_data;
+ tx = xennet_make_one_txreq(queue, skb_get(skb),
+ page, offset, len);
+ page++;
+ offset = 0;
+ len -= tx->size;
}
- queue->tx.req_prod_pvt = prod;
+ return tx;
}
/*
@@ -565,18 +522,15 @@ static u16 xennet_select_queue(struct net_device *dev,
struct sk_buff *skb,
static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
- unsigned short id;
struct netfront_info *np = netdev_priv(dev);
struct netfront_stats *stats = this_cpu_ptr(np->stats);
- struct xen_netif_tx_request *tx;
- char *data = skb->data;
- RING_IDX i;
- grant_ref_t ref;
- unsigned long mfn;
+ struct xen_netif_tx_request *tx, *first_tx;
+ unsigned int i;
int notify;
int slots;
- unsigned int offset = offset_in_page(data);
- unsigned int len = skb_headlen(skb);
+ struct page *page;
+ unsigned int offset;
+ unsigned int len;
unsigned long flags;
struct netfront_queue *queue = NULL;
unsigned int num_queues = dev->real_num_tx_queues;
@@ -605,11 +559,12 @@ static int xennet_start_xmit(struct sk_buff *skb, struct
net_device *dev)
slots, skb->len);
if (skb_linearize(skb))
goto drop;
- data = skb->data;
- offset = offset_in_page(data);
- len = skb_headlen(skb);
}
+ page = virt_to_page(skb->data);
+ offset = offset_in_page(skb->data);
+ len = skb_headlen(skb);
+
spin_lock_irqsave(&queue->tx_lock, flags);
if (unlikely(!netif_carrier_ok(dev) ||
@@ -619,25 +574,13 @@ static int xennet_start_xmit(struct sk_buff *skb, struct
net_device *dev)
goto drop;
}
- i = queue->tx.req_prod_pvt;
-
- id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
- queue->tx_skbs[id].skb = skb;
-
- tx = RING_GET_REQUEST(&queue->tx, i);
+ /* First request for the linear area. */
+ first_tx = tx = xennet_make_one_txreq(queue, skb,
+ page, offset, len);
+ page++;
+ offset = 0;
+ len -= tx->size;
- tx->id = id;
- ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
- BUG_ON((signed short)ref < 0);
- mfn = virt_to_mfn(data);
- gnttab_grant_foreign_access_ref(
- ref, queue->info->xbdev->otherend_id, mfn, GNTMAP_readonly);
- queue->grant_tx_page[id] = virt_to_page(data);
- tx->gref = queue->grant_tx_ref[id] = ref;
- tx->offset = offset;
- tx->size = len;
-
- tx->flags = 0;
if (skb->ip_summed == CHECKSUM_PARTIAL)
/* local packet? */
tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
@@ -645,11 +588,12 @@ static int xennet_start_xmit(struct sk_buff *skb, struct
net_device *dev)
/* remote but checksummed. */
tx->flags |= XEN_NETTXF_data_validated;
+ /* Optional extra info after the first request. */
if (skb_shinfo(skb)->gso_size) {
struct xen_netif_extra_info *gso;
gso = (struct xen_netif_extra_info *)
- RING_GET_REQUEST(&queue->tx, ++i);
+ RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
tx->flags |= XEN_NETTXF_extra_info;
@@ -664,10 +608,19 @@ static int xennet_start_xmit(struct sk_buff *skb, struct
net_device *dev)
gso->flags = 0;
}
- queue->tx.req_prod_pvt = i + 1;
+ /* Requests for the rest of the linear area. */
+ tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
+
+ /* Requests for all the frags. */
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+ tx = xennet_make_txreqs(queue, tx, skb,
+ skb_frag_page(frag), frag->page_offset,
+ skb_frag_size(frag));
+ }
- xennet_make_frags(skb, queue, tx);
- tx->size = skb->len;
+ /* First request has the packet length. */
+ first_tx->size = skb->len;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
if (notify)
--
1.7.10.4
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