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xen-netback: support multiple extra info fragments passed from frontend
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The code does not currently support a frontend passing multiple extra info
fragments to the backend in a tx request. The xenvif_get_extras() function
handles multiple extra_info fragments but make_tx_response() assumes there
is only ever a single extra info fragment.

This patch modifies xenvif_get_extras() to pass back a count of extra
info fragments, which is then passed to make_tx_response() (after
possibly being stashed in pending_tx_info for deferred responses).

Signed-off-by: Paul Durrant <[email protected]>
Cc: Wei Liu <[email protected]>
Acked-by: Wei Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@davem330
Paul Durrant authored and davem330 committed Mar 14, 2016
1 parent 6b8abef commit 562abd3
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Showing 2 changed files with 43 additions and 23 deletions.
1 change: 1 addition & 0 deletions drivers/net/xen-netback/common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,7 @@ typedef unsigned int pending_ring_idx_t;

struct pending_tx_info {
struct xen_netif_tx_request req; /* tx request */
unsigned int extra_count;
/* Callback data for released SKBs. The callback is always
* xenvif_zerocopy_callback, desc contains the pending_idx, which is
* also an index in pending_tx_info array. It is initialized in
Expand Down
65 changes: 42 additions & 23 deletions drivers/net/xen-netback/netback.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,

static void make_tx_response(struct xenvif_queue *queue,
struct xen_netif_tx_request *txp,
unsigned int extra_count,
s8 st);
static void push_tx_responses(struct xenvif_queue *queue);

Expand Down Expand Up @@ -696,14 +697,15 @@ void xenvif_tx_credit_callback(unsigned long data)
}

static void xenvif_tx_err(struct xenvif_queue *queue,
struct xen_netif_tx_request *txp, RING_IDX end)
struct xen_netif_tx_request *txp,
unsigned int extra_count, RING_IDX end)
{
RING_IDX cons = queue->tx.req_cons;
unsigned long flags;

do {
spin_lock_irqsave(&queue->response_lock, flags);
make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
push_tx_responses(queue);
spin_unlock_irqrestore(&queue->response_lock, flags);
if (cons == end)
Expand All @@ -724,6 +726,7 @@ static void xenvif_fatal_tx_err(struct xenvif *vif)

static int xenvif_count_requests(struct xenvif_queue *queue,
struct xen_netif_tx_request *first,
unsigned int extra_count,
struct xen_netif_tx_request *txp,
int work_to_do)
{
Expand Down Expand Up @@ -812,7 +815,7 @@ static int xenvif_count_requests(struct xenvif_queue *queue,
} while (more_data);

if (drop_err) {
xenvif_tx_err(queue, first, cons + slots);
xenvif_tx_err(queue, first, extra_count, cons + slots);
return drop_err;
}

Expand All @@ -827,9 +830,10 @@ struct xenvif_tx_cb {
#define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)

static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
u16 pending_idx,
struct xen_netif_tx_request *txp,
struct gnttab_map_grant_ref *mop)
u16 pending_idx,
struct xen_netif_tx_request *txp,
unsigned int extra_count,
struct gnttab_map_grant_ref *mop)
{
queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
Expand All @@ -838,6 +842,7 @@ static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,

memcpy(&queue->pending_tx_info[pending_idx].req, txp,
sizeof(*txp));
queue->pending_tx_info[pending_idx].extra_count = extra_count;
}

static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
Expand Down Expand Up @@ -880,7 +885,7 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que
shinfo->nr_frags++, txp++, gop++) {
index = pending_index(queue->pending_cons++);
pending_idx = queue->pending_ring[index];
xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
}

Expand All @@ -893,7 +898,8 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que
shinfo->nr_frags++, txp++, gop++) {
index = pending_index(queue->pending_cons++);
pending_idx = queue->pending_ring[index];
xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
gop);
frag_set_pending_idx(&frags[shinfo->nr_frags],
pending_idx);
}
Expand Down Expand Up @@ -1095,8 +1101,9 @@ static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
}

static int xenvif_get_extras(struct xenvif_queue *queue,
struct xen_netif_extra_info *extras,
int work_to_do)
struct xen_netif_extra_info *extras,
unsigned int *extra_count,
int work_to_do)
{
struct xen_netif_extra_info extra;
RING_IDX cons = queue->tx.req_cons;
Expand All @@ -1109,17 +1116,19 @@ static int xenvif_get_extras(struct xenvif_queue *queue,
}

RING_COPY_REQUEST(&queue->tx, cons, &extra);

queue->tx.req_cons = ++cons;
(*extra_count)++;

if (unlikely(!extra.type ||
extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
queue->tx.req_cons = ++cons;
netdev_err(queue->vif->dev,
"Invalid extra type: %d\n", extra.type);
xenvif_fatal_tx_err(queue->vif);
return -EINVAL;
}

memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
queue->tx.req_cons = ++cons;
} while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);

return work_to_do;
Expand Down Expand Up @@ -1294,6 +1303,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
struct xen_netif_tx_request txreq;
struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
unsigned int extra_count;
u16 pending_idx;
RING_IDX idx;
int work_to_do;
Expand Down Expand Up @@ -1330,8 +1340,10 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
queue->tx.req_cons = ++idx;

memset(extras, 0, sizeof(extras));
extra_count = 0;
if (txreq.flags & XEN_NETTXF_extra_info) {
work_to_do = xenvif_get_extras(queue, extras,
&extra_count,
work_to_do);
idx = queue->tx.req_cons;
if (unlikely(work_to_do < 0))
Expand All @@ -1344,7 +1356,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);

make_tx_response(queue, &txreq,
make_tx_response(queue, &txreq, extra_count,
(ret == 0) ?
XEN_NETIF_RSP_OKAY :
XEN_NETIF_RSP_ERROR);
Expand All @@ -1358,12 +1370,14 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
xenvif_mcast_del(queue->vif, extra->u.mcast.addr);

make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);
make_tx_response(queue, &txreq, extra_count,
XEN_NETIF_RSP_OKAY);
push_tx_responses(queue);
continue;
}

ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
ret = xenvif_count_requests(queue, &txreq, extra_count,
txfrags, work_to_do);
if (unlikely(ret < 0))
break;

Expand All @@ -1372,7 +1386,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
if (unlikely(txreq.size < ETH_HLEN)) {
netdev_dbg(queue->vif->dev,
"Bad packet size: %d\n", txreq.size);
xenvif_tx_err(queue, &txreq, idx);
xenvif_tx_err(queue, &txreq, extra_count, idx);
break;
}

Expand All @@ -1397,7 +1411,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
if (unlikely(skb == NULL)) {
netdev_dbg(queue->vif->dev,
"Can't allocate a skb in start_xmit.\n");
xenvif_tx_err(queue, &txreq, idx);
xenvif_tx_err(queue, &txreq, extra_count, idx);
break;
}

Expand All @@ -1416,7 +1430,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
nskb = xenvif_alloc_skb(0);
if (unlikely(nskb == NULL)) {
kfree_skb(skb);
xenvif_tx_err(queue, &txreq, idx);
xenvif_tx_err(queue, &txreq, extra_count, idx);
if (net_ratelimit())
netdev_err(queue->vif->dev,
"Can't allocate the frag_list skb.\n");
Expand Down Expand Up @@ -1457,13 +1471,16 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
if (data_len < txreq.size) {
frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
pending_idx);
xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
xenvif_tx_create_map_op(queue, pending_idx, &txreq,
extra_count, gop);
gop++;
} else {
frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
INVALID_PENDING_IDX);
memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
sizeof(txreq));
memcpy(&queue->pending_tx_info[pending_idx].req,
&txreq, sizeof(txreq));
queue->pending_tx_info[pending_idx].extra_count =
extra_count;
}

queue->pending_cons++;
Expand Down Expand Up @@ -1804,7 +1821,8 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,

spin_lock_irqsave(&queue->response_lock, flags);

make_tx_response(queue, &pending_tx_info->req, status);
make_tx_response(queue, &pending_tx_info->req,
pending_tx_info->extra_count, status);

/* Release the pending index before pusing the Tx response so
* its available before a new Tx request is pushed by the
Expand All @@ -1821,6 +1839,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,

static void make_tx_response(struct xenvif_queue *queue,
struct xen_netif_tx_request *txp,
unsigned int extra_count,
s8 st)
{
RING_IDX i = queue->tx.rsp_prod_pvt;
Expand All @@ -1830,7 +1849,7 @@ static void make_tx_response(struct xenvif_queue *queue,
resp->id = txp->id;
resp->status = st;

if (txp->flags & XEN_NETTXF_extra_info)
while (extra_count-- != 0)
RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;

queue->tx.rsp_prod_pvt = ++i;
Expand Down

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