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xen-netfront: refactor making Tx requests

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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@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Vrabel 2015-01-13 17:16:44 +00:00 committed by David S. Miller
parent e84448d521
commit a55e8bb8fb
1 changed files with 71 additions and 118 deletions
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189
drivers/net/xen-netfront.c
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@ -421,99 +421,56 @@ 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)
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)
{
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);
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;
len = min_t(unsigned int, PAGE_SIZE - offset, len);
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);
gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
page_to_mfn(page), GNTMAP_readonly);
queue->tx_skbs[id].skb = skb;
queue->grant_tx_page[id] = page;
queue->grant_tx_ref[id] = ref;
tx->id = id;
tx->gref = ref;
tx->offset = offset;
tx->size = len;
tx->flags = 0;
return tx;
}
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) {
tx->flags |= XEN_NETTXF_more_data;
len -= tx->size;
data += tx->size;
tx = xennet_make_one_txreq(queue, skb_get(skb),
page, offset, len);
page++;
offset = 0;
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 = 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;
len -= tx->size;
}
/* 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);
len = skb_frag_size(frag);
offset = frag->page_offset;
/* 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;
}
}
}
queue->tx.req_prod_pvt = prod;
return tx;
}
/*
@ -561,18 +518,15 @@ 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;
@ -601,11 +555,12 @@ 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) ||
@ -615,25 +570,13 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
goto drop;
}
i = queue->tx.req_prod_pvt;
/* First request for the linear area. */
first_tx = tx = xennet_make_one_txreq(queue, skb,
page, offset, len);
page++;
offset = 0;
len -= tx->size;
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);
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;
@ -641,11 +584,12 @@ 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;
@ -660,10 +604,19 @@ 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);
xennet_make_frags(skb, queue, tx);
tx->size = skb->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));
}
/* First request has the packet length. */
first_tx->size = skb->len;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
if (notify)