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xen-netback: refactor guest rx

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Refactor the to-guest (rx) path to:

1. Push responses for completed skbs earlier, reducing latency.

2. Reduce the per-queue memory overhead by greatly reducing the
   maximum number of grant copy ops in each hypercall (from 4352 to
   64).  Each struct xenvif_queue is now only 44 kB instead of 220 kB.

3. Make the code more maintainable.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[re-based]
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Vrabel 2016-10-04 10:29:14 +01:00 committed by David S. Miller
parent fedbc8c132
commit eb1723a29b
2 changed files with 254 additions and 423 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

23
drivers/net/xen-netback/common.h
View file

@ -91,13 +91,6 @@ struct xenvif_rx_meta {
*/
#define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
/* It's possible for an skb to have a maximal number of frags
* but still be less than MAX_BUFFER_OFFSET in size. Thus the
* worst-case number of copy operations is MAX_XEN_SKB_FRAGS per
* ring slot.
*/
#define MAX_GRANT_COPY_OPS (MAX_XEN_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
#define NETBACK_INVALID_HANDLE -1
/* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
@ -133,6 +126,14 @@ struct xenvif_stats {
unsigned long tx_frag_overflow;
};
#define COPY_BATCH_SIZE 64
struct xenvif_copy_state {
struct gnttab_copy op[COPY_BATCH_SIZE];
RING_IDX idx[COPY_BATCH_SIZE];
unsigned int num;
};
struct xenvif_queue { /* Per-queue data for xenvif */
unsigned int id; /* Queue ID, 0-based */
char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
@ -189,12 +190,7 @@ struct xenvif_queue { /* Per-queue data for xenvif */
unsigned long last_rx_time;
bool stalled;
struct gnttab_copy grant_copy_op[MAX_GRANT_COPY_OPS];
/* We create one meta structure per ring request we consume, so
* the maximum number is the same as the ring size.
*/
struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
struct xenvif_copy_state rx_copy;
/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
unsigned long credit_bytes;
@ -358,6 +354,7 @@ int xenvif_dealloc_kthread(void *data);
irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data);
void xenvif_rx_action(struct xenvif_queue *queue);
void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
void xenvif_carrier_on(struct xenvif *vif);

654
drivers/net/xen-netback/rx.c
View file

@ -26,7 +26,6 @@
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "common.h"
#include <linux/kthread.h>
@ -137,464 +136,299 @@ static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
}
}
struct netrx_pending_operations {
unsigned int copy_prod, copy_cons;
unsigned int meta_prod, meta_cons;
struct gnttab_copy *copy;
struct xenvif_rx_meta *meta;
int copy_off;
grant_ref_t copy_gref;
};
static struct xenvif_rx_meta *get_next_rx_buffer(
struct xenvif_queue *queue,
struct netrx_pending_operations *npo)
static void xenvif_rx_copy_flush(struct xenvif_queue *queue)
{
struct xenvif_rx_meta *meta;
struct xen_netif_rx_request req;
unsigned int i;
RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
gnttab_batch_copy(queue->rx_copy.op, queue->rx_copy.num);
meta = npo->meta + npo->meta_prod++;
meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
meta->gso_size = 0;
meta->size = 0;
meta->id = req.id;
for (i = 0; i < queue->rx_copy.num; i++) {
struct gnttab_copy *op;
npo->copy_off = 0;
npo->copy_gref = req.gref;
op = &queue->rx_copy.op[i];
return meta;
/* If the copy failed, overwrite the status field in
* the corresponding response.
*/
if (unlikely(op->status != GNTST_okay)) {
struct xen_netif_rx_response *rsp;
rsp = RING_GET_RESPONSE(&queue->rx,
queue->rx_copy.idx[i]);
rsp->status = op->status;
}
}
queue->rx_copy.num = 0;
}
struct gop_frag_copy {
struct xenvif_queue *queue;
struct netrx_pending_operations *npo;
struct xenvif_rx_meta *meta;
int head;
int gso_type;
int protocol;
int hash_present;
struct page *page;
};
static void xenvif_setup_copy_gop(unsigned long gfn,
unsigned int offset,
unsigned int *len,
struct gop_frag_copy *info)
static void xenvif_rx_copy_add(struct xenvif_queue *queue,
struct xen_netif_rx_request *req,
unsigned int offset, void *data, size_t len)
{
struct gnttab_copy *copy_gop;
struct gnttab_copy *op;
struct page *page;
struct xen_page_foreign *foreign;
/* Convenient aliases */
struct xenvif_queue *queue = info->queue;
struct netrx_pending_operations *npo = info->npo;
struct page *page = info->page;
WARN_ON(npo->copy_off > MAX_BUFFER_OFFSET);
if (queue->rx_copy.num == COPY_BATCH_SIZE)
xenvif_rx_copy_flush(queue);
if (npo->copy_off == MAX_BUFFER_OFFSET)
info->meta = get_next_rx_buffer(queue, npo);
op = &queue->rx_copy.op[queue->rx_copy.num];
if (npo->copy_off + *len > MAX_BUFFER_OFFSET)
*len = MAX_BUFFER_OFFSET - npo->copy_off;
page = virt_to_page(data);
copy_gop = npo->copy + npo->copy_prod++;
copy_gop->flags = GNTCOPY_dest_gref;
copy_gop->len = *len;
op->flags = GNTCOPY_dest_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;
op->source.domid = foreign->domid;
op->source.u.ref = foreign->gref;
op->flags |= GNTCOPY_source_gref;
} else {
copy_gop->source.domid = DOMID_SELF;
copy_gop->source.u.gmfn = gfn;
op->source.u.gmfn = virt_to_gfn(data);
op->source.domid = DOMID_SELF;
}
copy_gop->source.offset = offset;
copy_gop->dest.domid = queue->vif->domid;
copy_gop->dest.offset = npo->copy_off;
copy_gop->dest.u.ref = npo->copy_gref;
op->source.offset = xen_offset_in_page(data);
op->dest.u.ref = req->gref;
op->dest.domid = queue->vif->domid;
op->dest.offset = offset;
op->len = len;
npo->copy_off += *len;
info->meta->size += *len;
if (!info->head)
return;
/* Leave a gap for the GSO descriptor. */
if ((1 << info->gso_type) & queue->vif->gso_mask)
queue->rx.req_cons++;
/* Leave a gap for the hash extra segment. */
if (info->hash_present)
queue->rx.req_cons++;
info->head = 0; /* There must be something in this buffer now */
queue->rx_copy.idx[queue->rx_copy.num] = queue->rx.req_cons;
queue->rx_copy.num++;
}
static void xenvif_gop_frag_copy_grant(unsigned long gfn,
unsigned int offset,
unsigned int len,
void *data)
static unsigned int xenvif_gso_type(struct sk_buff *skb)
{
unsigned int bytes;
while (len) {
bytes = len;
xenvif_setup_copy_gop(gfn, offset, &bytes, data);
offset += bytes;
len -= bytes;
}
}
/* Set up the grant operations for this fragment. If it's a flipping
* interface, we also set up the unmap request from here.
*/
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 gop_frag_copy info = {
.queue = queue,
.npo = npo,
.head = *head,
.gso_type = XEN_NETIF_GSO_TYPE_NONE,
/* xenvif_set_skb_hash() will have either set a s/w
* hash or cleared the hash depending on
* whether the the frontend wants a hash for this skb.
*/
.hash_present = skb->sw_hash,
};
unsigned long bytes;
if (skb_is_gso(skb)) {
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
info.gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
info.gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
}
/* Data must not cross a page boundary. */
WARN_ON(size + offset > (PAGE_SIZE << compound_order(page)));
info.meta = npo->meta + npo->meta_prod - 1;
/* Skip unused frames from start of page */
page += offset >> PAGE_SHIFT;
offset &= ~PAGE_MASK;
while (size > 0) {
WARN_ON(offset >= PAGE_SIZE);
bytes = PAGE_SIZE - offset;
if (bytes > size)
bytes = size;
info.page = page;
gnttab_foreach_grant_in_range(page, offset, bytes,
xenvif_gop_frag_copy_grant,
&info);
size -= bytes;
offset = 0;
/* Next page */
if (size) {
WARN_ON(!PageCompound(page));
page++;
}
}
*head = info.head;
}
/* Prepare an SKB to be transmitted to the frontend.
*
* This function is responsible for allocating grant operations, meta
* structures, etc.
*
* It returns the number of meta structures consumed. The number of
* ring slots used is always equal to the number of meta slots used
* plus the number of GSO descriptors used. Currently, we use either
* zero GSO descriptors (for non-GSO packets) or one descriptor (for
* frontend-side LRO).
*/
static int xenvif_gop_skb(struct sk_buff *skb,
struct netrx_pending_operations *npo,
struct xenvif_queue *queue)
{
struct xenvif *vif = netdev_priv(skb->dev);
int nr_frags = skb_shinfo(skb)->nr_frags;
int i;
struct xen_netif_rx_request req;
struct xenvif_rx_meta *meta;
unsigned char *data;
int head = 1;
int old_meta_prod;
int gso_type;
old_meta_prod = npo->meta_prod;
gso_type = XEN_NETIF_GSO_TYPE_NONE;
if (skb_is_gso(skb)) {
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
gso_type = XEN_NETIF_GSO_TYPE_TCPV4;
else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
gso_type = XEN_NETIF_GSO_TYPE_TCPV6;
}
RING_COPY_REQUEST(&queue->rx, queue->rx.req_cons++, &req);
meta = npo->meta + npo->meta_prod++;
if ((1 << gso_type) & vif->gso_mask) {
meta->gso_type = gso_type;
meta->gso_size = skb_shinfo(skb)->gso_size;
} else {
meta->gso_type = XEN_NETIF_GSO_TYPE_NONE;
meta->gso_size = 0;
}
meta->size = 0;
meta->id = req.id;
npo->copy_off = 0;
npo->copy_gref = req.gref;
data = skb->data;
while (data < skb_tail_pointer(skb)) {
unsigned int offset = offset_in_page(data);
unsigned int len = PAGE_SIZE - offset;
if (data + len > skb_tail_pointer(skb))
len = skb_tail_pointer(skb) - data;
xenvif_gop_frag_copy(queue, skb, npo,
virt_to_page(data), len, offset, &head);
data += len;
}
for (i = 0; i < nr_frags; i++) {
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);
}
return npo->meta_prod - old_meta_prod;
}
/* This is a twin to xenvif_gop_skb. Assume that xenvif_gop_skb was
* used to set up the operations on the top of
* netrx_pending_operations, which have since been done. Check that
* they didn't give any errors and advance over them.
*/
static int xenvif_check_gop(struct xenvif *vif, int nr_meta_slots,
struct netrx_pending_operations *npo)
{
struct gnttab_copy *copy_op;
int status = XEN_NETIF_RSP_OKAY;
int i;
for (i = 0; i < nr_meta_slots; i++) {
copy_op = npo->copy + npo->copy_cons++;
if (copy_op->status != GNTST_okay) {
netdev_dbg(vif->dev,
"Bad status %d from copy to DOM%d.\n",
copy_op->status, vif->domid);
status = XEN_NETIF_RSP_ERROR;
}
}
return status;
}
static struct xen_netif_rx_response *make_rx_response(
struct xenvif_queue *queue, u16 id, s8 st, u16 offset, u16 size,
u16 flags)
{
RING_IDX i = queue->rx.rsp_prod_pvt;
struct xen_netif_rx_response *resp;
resp = RING_GET_RESPONSE(&queue->rx, i);
resp->offset = offset;
resp->flags = flags;
resp->id = id;
resp->status = (s16)size;
if (st < 0)
resp->status = (s16)st;
queue->rx.rsp_prod_pvt = ++i;
return resp;
}
static void xenvif_add_frag_responses(struct xenvif_queue *queue,
int status,
struct xenvif_rx_meta *meta,
int nr_meta_slots)
{
int i;
unsigned long offset;
/* No fragments used */
if (nr_meta_slots <= 1)
return;
nr_meta_slots--;
for (i = 0; i < nr_meta_slots; i++) {
int flags;
if (i == nr_meta_slots - 1)
flags = 0;
return XEN_NETIF_GSO_TYPE_TCPV4;
else
flags = XEN_NETRXF_more_data;
offset = 0;
make_rx_response(queue, meta[i].id, status, offset,
meta[i].size, flags);
return XEN_NETIF_GSO_TYPE_TCPV6;
}
return XEN_NETIF_GSO_TYPE_NONE;
}
static void xenvif_rx_action(struct xenvif_queue *queue)
{
struct xenvif *vif = queue->vif;
s8 status;
u16 flags;
struct xen_netif_rx_response *resp;
struct sk_buff_head rxq;
struct xenvif_pkt_state {
struct sk_buff *skb;
LIST_HEAD(notify);
int ret;
unsigned long offset;
bool need_to_notify = false;
size_t remaining_len;
int frag; /* frag == -1 => skb->head */
unsigned int frag_offset;
struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
unsigned int extra_count;
unsigned int slot;
};
struct netrx_pending_operations npo = {
.copy = queue->grant_copy_op,
.meta = queue->meta,
};
static void xenvif_rx_next_skb(struct xenvif_queue *queue,
struct xenvif_pkt_state *pkt)
{
struct sk_buff *skb;
unsigned int gso_type;
skb_queue_head_init(&rxq);
skb = xenvif_rx_dequeue(queue);
while (xenvif_rx_ring_slots_available(queue) &&
(skb = xenvif_rx_dequeue(queue)) != NULL) {
queue->last_rx_time = jiffies;
queue->stats.tx_bytes += skb->len;
queue->stats.tx_packets++;
XENVIF_RX_CB(skb)->meta_slots_used =
xenvif_gop_skb(skb, &npo, queue);
/* Reset packet state. */
memset(pkt, 0, sizeof(struct xenvif_pkt_state));
__skb_queue_tail(&rxq, skb);
pkt->skb = skb;
pkt->remaining_len = skb->len;
pkt->frag = -1;
gso_type = xenvif_gso_type(skb);
if ((1 << gso_type) & queue->vif->gso_mask) {
struct xen_netif_extra_info *extra;
extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
extra->u.gso.type = gso_type;
extra->u.gso.size = skb_shinfo(skb)->gso_size;
extra->u.gso.pad = 0;
extra->u.gso.features = 0;
extra->type = XEN_NETIF_EXTRA_TYPE_GSO;
extra->flags = 0;
pkt->extra_count++;
}
WARN_ON(npo.meta_prod > ARRAY_SIZE(queue->meta));
if (skb->sw_hash) {
struct xen_netif_extra_info *extra;
if (!npo.copy_prod)
goto done;
extra = &pkt->extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
WARN_ON(npo.copy_prod > MAX_GRANT_COPY_OPS);
gnttab_batch_copy(queue->grant_copy_op, npo.copy_prod);
extra->u.hash.algorithm =
XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ;
while ((skb = __skb_dequeue(&rxq)) != NULL) {
struct xen_netif_extra_info *extra = NULL;
queue->stats.tx_bytes += skb->len;
queue->stats.tx_packets++;
status = xenvif_check_gop(vif,
XENVIF_RX_CB(skb)->meta_slots_used,
&npo);
if (XENVIF_RX_CB(skb)->meta_slots_used == 1)
flags = 0;
if (skb->l4_hash)
extra->u.hash.type =
skb->protocol == htons(ETH_P_IP) ?
_XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP :
_XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
else
flags = XEN_NETRXF_more_data;
extra->u.hash.type =
skb->protocol == htons(ETH_P_IP) ?
_XEN_NETIF_CTRL_HASH_TYPE_IPV4 :
_XEN_NETIF_CTRL_HASH_TYPE_IPV6;
if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
*(uint32_t *)extra->u.hash.value = skb_get_hash_raw(skb);
extra->type = XEN_NETIF_EXTRA_TYPE_HASH;
extra->flags = 0;
pkt->extra_count++;
}
}
static void xenvif_rx_complete(struct xenvif_queue *queue,
struct xenvif_pkt_state *pkt)
{
int notify;
/* Complete any outstanding copy ops for this skb. */
xenvif_rx_copy_flush(queue);
/* Push responses and notify. */
queue->rx.rsp_prod_pvt = queue->rx.req_cons;
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, notify);
if (notify)
notify_remote_via_irq(queue->rx_irq);
dev_kfree_skb(pkt->skb);
}
static void xenvif_rx_next_chunk(struct xenvif_queue *queue,
struct xenvif_pkt_state *pkt,
unsigned int offset, void **data,
size_t *len)
{
struct sk_buff *skb = pkt->skb;
void *frag_data;
size_t frag_len, chunk_len;
if (pkt->frag == -1) {
frag_data = skb->data;
frag_len = skb_headlen(skb);
} else {
skb_frag_t *frag = &skb_shinfo(skb)->frags[pkt->frag];
frag_data = skb_frag_address(frag);
frag_len = skb_frag_size(frag);
}
frag_data += pkt->frag_offset;
frag_len -= pkt->frag_offset;
chunk_len = min(frag_len, XEN_PAGE_SIZE - offset);
chunk_len = min(chunk_len,
XEN_PAGE_SIZE - xen_offset_in_page(frag_data));
pkt->frag_offset += chunk_len;
/* Advance to next frag? */
if (frag_len == chunk_len) {
pkt->frag++;
pkt->frag_offset = 0;
}
*data = frag_data;
*len = chunk_len;
}
static void xenvif_rx_data_slot(struct xenvif_queue *queue,
struct xenvif_pkt_state *pkt,
struct xen_netif_rx_request *req,
struct xen_netif_rx_response *rsp)
{
unsigned int offset = 0;
unsigned int flags;
do {
size_t len;
void *data;
xenvif_rx_next_chunk(queue, pkt, offset, &data, &len);
xenvif_rx_copy_add(queue, req, offset, data, len);
offset += len;
pkt->remaining_len -= len;
} while (offset < XEN_PAGE_SIZE && pkt->remaining_len > 0);
if (pkt->remaining_len > 0)
flags = XEN_NETRXF_more_data;
else
flags = 0;
if (pkt->slot == 0) {
struct sk_buff *skb = pkt->skb;
if (skb->ip_summed == CHECKSUM_PARTIAL)
flags |= XEN_NETRXF_csum_blank |
XEN_NETRXF_data_validated;
else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
/* remote but checksummed. */
flags |= XEN_NETRXF_data_validated;
offset = 0;
resp = make_rx_response(queue, queue->meta[npo.meta_cons].id,
status, offset,
queue->meta[npo.meta_cons].size,
flags);
if ((1 << queue->meta[npo.meta_cons].gso_type) &
vif->gso_mask) {
extra = (struct xen_netif_extra_info *)
RING_GET_RESPONSE(&queue->rx,
queue->rx.rsp_prod_pvt++);
resp->flags |= XEN_NETRXF_extra_info;
extra->u.gso.type = queue->meta[npo.meta_cons].gso_type;
extra->u.gso.size = queue->meta[npo.meta_cons].gso_size;
extra->u.gso.pad = 0;
extra->u.gso.features = 0;
extra->type = XEN_NETIF_EXTRA_TYPE_GSO;
extra->flags = 0;
}
if (skb->sw_hash) {
/* Since the skb got here via xenvif_select_queue()
* we know that the hash has been re-calculated
* according to a configuration set by the frontend
* and therefore we know that it is legitimate to
* pass it to the frontend.
*/
if (resp->flags & XEN_NETRXF_extra_info)
extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
else
resp->flags |= XEN_NETRXF_extra_info;
extra = (struct xen_netif_extra_info *)
RING_GET_RESPONSE(&queue->rx,
queue->rx.rsp_prod_pvt++);
extra->u.hash.algorithm =
XEN_NETIF_CTRL_HASH_ALGORITHM_TOEPLITZ;
if (skb->l4_hash)
extra->u.hash.type =
skb->protocol == htons(ETH_P_IP) ?
_XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP :
_XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP;
else
extra->u.hash.type =
skb->protocol == htons(ETH_P_IP) ?
_XEN_NETIF_CTRL_HASH_TYPE_IPV4 :
_XEN_NETIF_CTRL_HASH_TYPE_IPV6;
*(uint32_t *)extra->u.hash.value =
skb_get_hash_raw(skb);
extra->type = XEN_NETIF_EXTRA_TYPE_HASH;
extra->flags = 0;
}
xenvif_add_frag_responses(queue, status,
queue->meta + npo.meta_cons + 1,
XENVIF_RX_CB(skb)->meta_slots_used);
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->rx, ret);
need_to_notify |= !!ret;
npo.meta_cons += XENVIF_RX_CB(skb)->meta_slots_used;
dev_kfree_skb(skb);
if (pkt->extra_count != 0)
flags |= XEN_NETRXF_extra_info;
}
done:
if (need_to_notify)
notify_remote_via_irq(queue->rx_irq);
rsp->offset = 0;
rsp->flags = flags;
rsp->id = req->id;
rsp->status = (s16)offset;
}
static void xenvif_rx_extra_slot(struct xenvif_queue *queue,
struct xenvif_pkt_state *pkt,
struct xen_netif_rx_request *req,
struct xen_netif_rx_response *rsp)
{
struct xen_netif_extra_info *extra = (void *)rsp;
unsigned int i;
pkt->extra_count--;
for (i = 0; i < ARRAY_SIZE(pkt->extras); i++) {
if (pkt->extras[i].type) {
*extra = pkt->extras[i];
if (pkt->extra_count != 0)
extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
pkt->extras[i].type = 0;
return;
}
}
BUG();
}
void xenvif_rx_action(struct xenvif_queue *queue)
{
struct xenvif_pkt_state pkt;
xenvif_rx_next_skb(queue, &pkt);
do {
struct xen_netif_rx_request *req;
struct xen_netif_rx_response *rsp;
req = RING_GET_REQUEST(&queue->rx, queue->rx.req_cons);
rsp = RING_GET_RESPONSE(&queue->rx, queue->rx.req_cons);
/* Extras must go after the first data slot */
if (pkt.slot != 0 && pkt.extra_count != 0)
xenvif_rx_extra_slot(queue, &pkt, req, rsp);
else
xenvif_rx_data_slot(queue, &pkt, req, rsp);
queue->rx.req_cons++;
pkt.slot++;
} while (pkt.remaining_len > 0 || pkt.extra_count != 0);
xenvif_rx_complete(queue, &pkt);
}
static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)