From ac69c26e7accb04ae2cb9ab0872068983a42b3c8 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Thu, 2 May 2013 00:43:57 +0000 Subject: xen-netback: remove redundent parameter in netbk_count_requests Tracking down from the caller, first_idx is always equal to vif->tx.req_cons. Remove it to avoid confusion. Suggested-by: Jan Beulich Signed-off-by: Wei Liu Acked-by: Ian Campbell Signed-off-by: David S. Miller --- drivers/net/xen-netback/netback.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'drivers/net/xen-netback/netback.c') diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index a2865f17c667..c44772d6bba0 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -928,7 +928,6 @@ static void netbk_fatal_tx_err(struct xenvif *vif) static int netbk_count_requests(struct xenvif *vif, struct xen_netif_tx_request *first, - RING_IDX first_idx, struct xen_netif_tx_request *txp, int work_to_do) { @@ -1005,7 +1004,7 @@ static int netbk_count_requests(struct xenvif *vif, } while ((txp++)->flags & XEN_NETTXF_more_data); if (drop_err) { - netbk_tx_err(vif, first, first_idx + slots); + netbk_tx_err(vif, first, cons + slots); return drop_err; } @@ -1470,8 +1469,7 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) continue; } - ret = netbk_count_requests(vif, &txreq, idx, - txfrags, work_to_do); + ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do); if (unlikely(ret < 0)) continue; -- cgit v1.2.3 From 59ccb4ebbc35e36a3c143f2d1355deb75c2e628f Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Thu, 2 May 2013 00:43:58 +0000 Subject: xen-netback: avoid allocating variable size array on stack 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 Signed-off-by: Wei Liu Signed-off-by: David S. Miller --- drivers/net/xen-netback/netback.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'drivers/net/xen-netback/netback.c') diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index c44772d6bba0..ce8109f7d56f 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); @@ -1408,7 +1420,7 @@ 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; -- cgit v1.2.3 From 376414945d15aa636e65f7e773c1e398b7a21cb9 Mon Sep 17 00:00:00 2001 From: Wei Liu Date: Thu, 2 May 2013 00:43:59 +0000 Subject: xen-netback: better names for thresholds This patch only changes some names to avoid confusion. In this patch we have: MAX_SKB_SLOTS_DEFAULT -> FATAL_SKB_SLOTS_DEFAULT max_skb_slots -> fatal_skb_slots #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN The fatal_skb_slots is the threshold to determine whether a packet is malicious. XEN_NETBK_LEGACY_SLOTS_MAX is the maximum slots a valid packet can have at this point. It is defined to be XEN_NETIF_NR_SLOTS_MIN because that's guaranteed to be supported by all backends. Suggested-by: Ian Campbell Signed-off-by: Wei Liu Signed-off-by: David S. Miller --- drivers/net/xen-netback/netback.c | 49 +++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 20 deletions(-) (limited to 'drivers/net/xen-netback/netback.c') diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index ce8109f7d56f..37984e6d4e99 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -51,9 +51,17 @@ * This is the maximum slots a skb can have. If a guest sends a skb * which exceeds this limit it is considered malicious. */ -#define MAX_SKB_SLOTS_DEFAULT 20 -static unsigned int max_skb_slots = MAX_SKB_SLOTS_DEFAULT; -module_param(max_skb_slots, uint, 0444); +#define FATAL_SKB_SLOTS_DEFAULT 20 +static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT; +module_param(fatal_skb_slots, uint, 0444); + +/* + * To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating + * the maximum slots a valid packet can use. Now this value is defined + * to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by + * all backend. + */ +#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN typedef unsigned int pending_ring_idx_t; #define INVALID_PENDING_RING_IDX (~0U) @@ -953,25 +961,26 @@ static int netbk_count_requests(struct xenvif *vif, /* This guest is really using too many slots and * considered malicious. */ - if (unlikely(slots >= max_skb_slots)) { + if (unlikely(slots >= fatal_skb_slots)) { netdev_err(vif->dev, "Malicious frontend using %d slots, threshold %u\n", - slots, max_skb_slots); + slots, fatal_skb_slots); netbk_fatal_tx_err(vif); return -E2BIG; } /* Xen network protocol had implicit dependency on - * MAX_SKB_FRAGS. XEN_NETIF_NR_SLOTS_MIN is set to the - * historical MAX_SKB_FRAGS value 18 to honor the same - * behavior as before. Any packet using more than 18 - * slots but less than max_skb_slots slots is dropped + * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to + * the historical MAX_SKB_FRAGS value 18 to honor the + * same behavior as before. Any packet using more than + * 18 slots but less than fatal_skb_slots slots is + * dropped */ - if (!drop_err && slots >= XEN_NETIF_NR_SLOTS_MIN) { + if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) { if (net_ratelimit()) netdev_dbg(vif->dev, "Too many slots (%d) exceeding limit (%d), dropping packet\n", - slots, XEN_NETIF_NR_SLOTS_MIN); + slots, XEN_NETBK_LEGACY_SLOTS_MAX); drop_err = -E2BIG; } @@ -1053,7 +1062,7 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk, struct pending_tx_info *first = NULL; /* At this point shinfo->nr_frags is in fact the number of - * slots, which can be as large as XEN_NETIF_NR_SLOTS_MIN. + * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. */ nr_slots = shinfo->nr_frags; @@ -1415,12 +1424,12 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) struct sk_buff *skb; int ret; - while ((nr_pending_reqs(netbk) + XEN_NETIF_NR_SLOTS_MIN + while ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX < MAX_PENDING_REQS) && !list_empty(&netbk->net_schedule_list)) { struct xenvif *vif; struct xen_netif_tx_request txreq; - struct xen_netif_tx_request txfrags[XEN_NETIF_NR_SLOTS_MIN]; + struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX]; struct page *page; struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1]; u16 pending_idx; @@ -1508,7 +1517,7 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk) pending_idx = netbk->pending_ring[index]; data_len = (txreq.size > PKT_PROT_LEN && - ret < XEN_NETIF_NR_SLOTS_MIN) ? + ret < XEN_NETBK_LEGACY_SLOTS_MAX) ? PKT_PROT_LEN : txreq.size; skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN, @@ -1787,7 +1796,7 @@ static inline int rx_work_todo(struct xen_netbk *netbk) static inline int tx_work_todo(struct xen_netbk *netbk) { - if ((nr_pending_reqs(netbk) + XEN_NETIF_NR_SLOTS_MIN + if ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX < MAX_PENDING_REQS) && !list_empty(&netbk->net_schedule_list)) return 1; @@ -1872,11 +1881,11 @@ static int __init netback_init(void) if (!xen_domain()) return -ENODEV; - if (max_skb_slots < XEN_NETIF_NR_SLOTS_MIN) { + if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) { printk(KERN_INFO - "xen-netback: max_skb_slots too small (%d), bump it to XEN_NETIF_NR_SLOTS_MIN (%d)\n", - max_skb_slots, XEN_NETIF_NR_SLOTS_MIN); - max_skb_slots = XEN_NETIF_NR_SLOTS_MIN; + "xen-netback: fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n", + fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX); + fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX; } xen_netbk_group_nr = num_online_cpus(); -- cgit v1.2.3