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authorWei Liu <wei.liu2@citrix.com>2013-05-02 00:43:58 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-07 12:53:36 -0700
commitd05a2b14b1b8263ab7467076cdf842b673695267 (patch)
treea64d76080ca401f740cf76cb4138ddf829bd0693
parent8660ef055e202b6f383fd7300a6cbc49c08eba89 (diff)
downloadvexpress-lsk-d05a2b14b1b8263ab7467076cdf842b673695267.tar.gz
xen-netback: avoid allocating variable size array on stack
commit 59ccb4ebbc35e36a3c143f2d1355deb75c2e628f upstream. Tune xen_netbk_count_requests to not touch working array beyond limit, so that we can make working array size constant. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/xen-netback/netback.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 4c497d0ea3d..b924c1a838d 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -934,11 +934,14 @@ static int netbk_count_requests(struct xenvif *vif,
RING_IDX cons = vif->tx.req_cons;
int slots = 0;
int drop_err = 0;
+ int more_data;
if (!(first->flags & XEN_NETTXF_more_data))
return 0;
do {
+ struct xen_netif_tx_request dropped_tx = { 0 };
+
if (slots >= work_to_do) {
netdev_err(vif->dev,
"Asked for %d slots but exceeds this limit\n",
@@ -972,6 +975,9 @@ static int netbk_count_requests(struct xenvif *vif,
drop_err = -E2BIG;
}
+ if (drop_err)
+ txp = &dropped_tx;
+
memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + slots),
sizeof(*txp));
@@ -1001,7 +1007,13 @@ static int netbk_count_requests(struct xenvif *vif,
netbk_fatal_tx_err(vif);
return -EINVAL;
}
- } while ((txp++)->flags & XEN_NETTXF_more_data);
+
+ more_data = txp->flags & XEN_NETTXF_more_data;
+
+ if (!drop_err)
+ txp++;
+
+ } while (more_data);
if (drop_err) {
netbk_tx_err(vif, first, cons + slots);
@@ -1413,7 +1425,7 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
!list_empty(&netbk->net_schedule_list)) {
struct xenvif *vif;
struct xen_netif_tx_request txreq;
- struct xen_netif_tx_request txfrags[max_skb_slots];
+ struct xen_netif_tx_request txfrags[XEN_NETIF_NR_SLOTS_MIN];
struct page *page;
struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
u16 pending_idx;