Re: 2.6.20-rc6-mm1

Ingo Molnar
2007-01-29T08:37:36Z

* Herbert Xu <herbert@gondor.apana.org.au> wrote:

> Actually, maybe I was confusing this with the fixes Ingo had for
> local_bh_disable vs. preemption in the -rt tree. Ingo, do you have
> preemptible RCU support in your -rt tree and if so did you have to fix
> the networking stack to behave correctly with it?

yeah, -rt is the main prototyping tree for PREEMPT_RCU, and it has been
included in -rt for 1.5 years or so. There were only some small things
here and there, but with Paul's latest design i dont remember anything
but the occasional place that needs to be marked raw_smp_processor_id().
CONFIG_DEBUG_PREEMPT ought to catch those. I dont remember any big
breakage.

i've just reviewed all changes to net/* in -rt, and the changes below
are the ones that seem to be upstream-relevant.

Ingo

Index: linux/net/ipv4/multipath_wrandom.c
===================================================================
--- linux.orig/net/ipv4/multipath_wrandom.c
+++ linux/net/ipv4/multipath_wrandom.c
@@ -301,6 +301,7 @@ static void wrandom_flush(void)
for (i = 0; i < MULTIPATH_STATE_SIZE; ++i) {
struct multipath_route *r;

+ rcu_read_lock();
spin_lock_bh(&state[i].lock);
list_for_each_entry_rcu(r, &state[i].head, list) {
struct multipath_dest *d;
@@ -315,6 +316,7 @@ static void wrandom_flush(void)
}

spin_unlock_bh(&state[i].lock);
+ rcu_read_unlock();
}
}

Index: linux/net/ipv4/netfilter/arp_tables.c
===================================================================
--- linux.orig/net/ipv4/netfilter/arp_tables.c
+++ linux/net/ipv4/netfilter/arp_tables.c
@@ -245,7 +245,7 @@ unsigned int arpt_do_table(struct sk_buf

read_lock_bh(&table->lock);
private = table->private;
- table_base = (void *)private->entries[smp_processor_id()];
+ table_base = (void *)private->entries[raw_smp_processor_id()];
e = get_entry(table_base, private->hook_entry[hook]);
back = get_entry(table_base, private->underflow[hook]);

@@ -955,7 +955,7 @@ static int do_add_counters(void __user *

i = 0;
/* Choose the copy that is on our node */
- loc_cpu_entry = private->entries[smp_processor_id()];
+ loc_cpu_entry = private->entries[raw_smp_processor_id()];
ARPT_ENTRY_ITERATE(loc_cpu_entry,
private->size,
add_counter_to_entry,
Index: linux/net/ipv4/netfilter/ip_tables.c
===================================================================
--- linux.orig/net/ipv4/netfilter/ip_tables.c
+++ linux/net/ipv4/netfilter/ip_tables.c
@@ -246,7 +246,7 @@ ipt_do_table(struct sk_buff **pskb,
read_lock_bh(&table->lock);
IP_NF_ASSERT(table->valid_hooks & (1 << hook));
private = table->private;
- table_base = (void *)private->entries[smp_processor_id()];
+ table_base = (void *)private->entries[raw_smp_processor_id()];
e = get_entry(table_base, private->hook_entry[hook]);

/* For return from builtin chain */
Index: linux/net/ipv4/tcp.c
===================================================================
--- linux.orig/net/ipv4/tcp.c
+++ linux/net/ipv4/tcp.c
@@ -1138,10 +1138,10 @@ int tcp_recvmsg(struct kiocb *iocb, stru
preempt_disable();
if ((len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
!sysctl_tcp_low_latency && __get_cpu_var(softnet_data).net_dma) {
- preempt_enable_no_resched();
+ preempt_enable();
tp->ucopy.pinned_list = dma_pin_iovec_pages(msg->msg_iov, len);
} else
- preempt_enable_no_resched();
+ preempt_enable();
#endif

do {
Index: linux/net/ipv6/netfilter/ip6_tables.c
===================================================================
--- linux.orig/net/ipv6/netfilter/ip6_tables.c
+++ linux/net/ipv6/netfilter/ip6_tables.c
@@ -282,7 +282,7 @@ ip6t_do_table(struct sk_buff **pskb,
read_lock_bh(&table->lock);
private = table->private;
IP_NF_ASSERT(table->valid_hooks & (1 << hook));
- table_base = (void *)private->entries[smp_processor_id()];
+ table_base = (void *)private->entries[raw_smp_processor_id()];
e = get_entry(table_base, private->hook_entry[hook]);

/* For return from builtin chain */
@@ -1097,7 +1097,7 @@ do_add_counters(void __user *user, unsig

i = 0;
/* Choose the copy that is on our node */
- loc_cpu_entry = private->entries[smp_processor_id()];
+ loc_cpu_entry = private->entries[raw_smp_processor_id()];
IP6T_ENTRY_ITERATE(loc_cpu_entry,
private->size,
add_counter_to_entry,
Index: linux/net/xfrm/xfrm_user.c
===================================================================
--- linux.orig/net/xfrm/xfrm_user.c
+++ linux/net/xfrm/xfrm_user.c
@@ -1273,13 +1273,12 @@ static int xfrm_get_policy(struct sk_buf
xp = xfrm_policy_bysel_ctx(type, p->dir, &p->sel, tmp.security, delete);
security_xfrm_policy_free(&tmp);
}
- if (delete)
- xfrm_audit_log(NETLINK_CB(skb).loginuid, NETLINK_CB(skb).sid,
- AUDIT_MAC_IPSEC_DELSPD, (xp) ? 1 : 0, xp, NULL);
-
if (xp == NULL)
return -ENOENT;

+ xfrm_audit_log(NETLINK_CB(skb).loginuid, NETLINK_CB(skb).sid,
+ AUDIT_MAC_IPSEC_DELSPD, delete, xp, NULL);
+
if (!delete) {
struct sk_buff *resp_skb;