From bb7ffb6b68a9be3ecdd3ce8ae333c4c0ce04cce7 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 30 Sep 2016 16:56:45 +0200 Subject: net: pktgen: fix pkt_size [ Upstream commit 63d75463c91a5b5be7c0aca11ceb45ea5a0ae81d ] The commit 879c7220e828 ("net: pktgen: Observe needed_headroom of the device") increased the 'pkt_overhead' field value by LL_RESERVED_SPACE. As a side effect the generated packet size, computed as: /* Eth + IPh + UDPh + mpls */ datalen = pkt_dev->cur_pkt_size - 14 - 20 - 8 - pkt_dev->pkt_overhead; is decreased by the same value. The above changed slightly the behavior of existing pktgen users, and made the procfs interface somewhat inconsistent. Fix it by restoring the previous pkt_overhead value and using LL_RESERVED_SPACE as extralen in skb allocation. Also, change pktgen_alloc_skb() to only partially reserve the headroom to allow the caller to prefetch from ll header start. v1 -> v2: - fixed some typos in the comments Fixes: 879c7220e828 ("net: pktgen: Observe needed_headroom of the device") Suggested-by: Ben Greear Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/pktgen.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) (limited to 'net/core/pktgen.c') diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 4da4d51a2ccf..cd794152abb1 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -2278,7 +2278,7 @@ static void spin(struct pktgen_dev *pkt_dev, ktime_t spin_until) static inline void set_pkt_overhead(struct pktgen_dev *pkt_dev) { - pkt_dev->pkt_overhead = LL_RESERVED_SPACE(pkt_dev->odev); + pkt_dev->pkt_overhead = 0; pkt_dev->pkt_overhead += pkt_dev->nr_labels*sizeof(u32); pkt_dev->pkt_overhead += VLAN_TAG_SIZE(pkt_dev); pkt_dev->pkt_overhead += SVLAN_TAG_SIZE(pkt_dev); @@ -2769,13 +2769,13 @@ static void pktgen_finalize_skb(struct pktgen_dev *pkt_dev, struct sk_buff *skb, } static struct sk_buff *pktgen_alloc_skb(struct net_device *dev, - struct pktgen_dev *pkt_dev, - unsigned int extralen) + struct pktgen_dev *pkt_dev) { + unsigned int extralen = LL_RESERVED_SPACE(dev); struct sk_buff *skb = NULL; - unsigned int size = pkt_dev->cur_pkt_size + 64 + extralen + - pkt_dev->pkt_overhead; + unsigned int size; + size = pkt_dev->cur_pkt_size + 64 + extralen + pkt_dev->pkt_overhead; if (pkt_dev->flags & F_NODE) { int node = pkt_dev->node >= 0 ? pkt_dev->node : numa_node_id(); @@ -2788,8 +2788,9 @@ static struct sk_buff *pktgen_alloc_skb(struct net_device *dev, skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT); } + /* the caller pre-fetches from skb->data and reserves for the mac hdr */ if (likely(skb)) - skb_reserve(skb, LL_RESERVED_SPACE(dev)); + skb_reserve(skb, extralen - 16); return skb; } @@ -2822,16 +2823,14 @@ static struct sk_buff *fill_packet_ipv4(struct net_device *odev, mod_cur_headers(pkt_dev); queue_map = pkt_dev->cur_queue_map; - datalen = (odev->hard_header_len + 16) & ~0xf; - - skb = pktgen_alloc_skb(odev, pkt_dev, datalen); + skb = pktgen_alloc_skb(odev, pkt_dev); if (!skb) { sprintf(pkt_dev->result, "No memory"); return NULL; } prefetchw(skb->data); - skb_reserve(skb, datalen); + skb_reserve(skb, 16); /* Reserve for ethernet and IP header */ eth = (__u8 *) skb_push(skb, 14); @@ -2951,7 +2950,7 @@ static struct sk_buff *fill_packet_ipv6(struct net_device *odev, mod_cur_headers(pkt_dev); queue_map = pkt_dev->cur_queue_map; - skb = pktgen_alloc_skb(odev, pkt_dev, 16); + skb = pktgen_alloc_skb(odev, pkt_dev); if (!skb) { sprintf(pkt_dev->result, "No memory"); return NULL; -- cgit v1.2.3 From f467184e2323db21d014ff72c65e3967b42e122a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 15 Oct 2016 17:50:49 +0200 Subject: net: pktgen: remove rcu locking in pktgen_change_name() [ Upstream commit 9a0b1e8ba4061778897b544afc898de2163382f7 ] After Jesper commit back in linux-3.18, we trigger a lockdep splat in proc_create_data() while allocating memory from pktgen_change_name(). This patch converts t->if_lock to a mutex, since it is now only used from control path, and adds proper locking to pktgen_change_name() 1) pktgen_thread_lock to protect the outer loop (iterating threads) 2) t->if_lock to protect the inner loop (iterating devices) Note that before Jesper patch, pktgen_change_name() was lacking proper protection, but lockdep was not able to detect the problem. Fixes: 8788370a1d4b ("pktgen: RCU-ify "if_list" to remove lock in next_to_run()") Reported-by: John Sperbeck Signed-off-by: Eric Dumazet Cc: Jesper Dangaard Brouer Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/pktgen.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'net/core/pktgen.c') diff --git a/net/core/pktgen.c b/net/core/pktgen.c index cd794152abb1..b6327601f979 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -215,8 +215,8 @@ #define M_NETIF_RECEIVE 1 /* Inject packets into stack */ /* If lock -- protects updating of if_list */ -#define if_lock(t) spin_lock(&(t->if_lock)); -#define if_unlock(t) spin_unlock(&(t->if_lock)); +#define if_lock(t) mutex_lock(&(t->if_lock)); +#define if_unlock(t) mutex_unlock(&(t->if_lock)); /* Used to help with determining the pkts on receive */ #define PKTGEN_MAGIC 0xbe9be955 @@ -422,7 +422,7 @@ struct pktgen_net { }; struct pktgen_thread { - spinlock_t if_lock; /* for list of devices */ + struct mutex if_lock; /* for list of devices */ struct list_head if_list; /* All device here */ struct list_head th_list; struct task_struct *tsk; @@ -2002,11 +2002,13 @@ static void pktgen_change_name(const struct pktgen_net *pn, struct net_device *d { struct pktgen_thread *t; + mutex_lock(&pktgen_thread_lock); + list_for_each_entry(t, &pn->pktgen_threads, th_list) { struct pktgen_dev *pkt_dev; - rcu_read_lock(); - list_for_each_entry_rcu(pkt_dev, &t->if_list, list) { + if_lock(t); + list_for_each_entry(pkt_dev, &t->if_list, list) { if (pkt_dev->odev != dev) continue; @@ -2021,8 +2023,9 @@ static void pktgen_change_name(const struct pktgen_net *pn, struct net_device *d dev->name); break; } - rcu_read_unlock(); + if_unlock(t); } + mutex_unlock(&pktgen_thread_lock); } static int pktgen_device_event(struct notifier_block *unused, @@ -3726,7 +3729,7 @@ static int __net_init pktgen_create_thread(int cpu, struct pktgen_net *pn) return -ENOMEM; } - spin_lock_init(&t->if_lock); + mutex_init(&t->if_lock); t->cpu = cpu; INIT_LIST_HEAD(&t->if_list); -- cgit v1.2.3