* Re: [PATCH] 2.5.68 - RCU for SNAP
2003-04-29 22:48 [PATCH] 2.5.68 - RCU for SNAP Stephen Hemminger
@ 2003-04-30 7:22 ` Arnaldo Carvalho de Melo
2003-04-30 6:34 ` David S. Miller
0 siblings, 1 reply; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2003-04-30 7:22 UTC (permalink / raw)
To: Stephen Hemminger; +Cc: David S. Miller, Jay Schulist, netdev
Hi,
Looks fine, applied, David, could you please pull from:
bk://kernel.bkbits.net/acme/net-2.5
Thanks Stephen.
- Arnaldo
You can import this changeset into BK by piping this whole message to:
'| bk receive [path to repository]' or apply the patch as usual.
===================================================================
ChangeSet@1.1170, 2003-04-30 04:17:25-03:00, shemminger@osdl.org
Replace br_lock() in snap with Read Copy Update.
Straightforward since SNAP uses list macros already.
Tested by bringing up/down Appletalk on SMP system and making sure packets
get through.
This is the last subsystem that depends on br_lock before IPV4,IPV6
can be converted.
psnap.c | 32 +++++++++++++++++---------------
1 files changed, 17 insertions(+), 15 deletions(-)
diff -Nru a/net/802/psnap.c b/net/802/psnap.c
--- a/net/802/psnap.c Wed Apr 30 04:20:09 2003
+++ b/net/802/psnap.c Wed Apr 30 04:20:09 2003
@@ -21,9 +21,9 @@
#include <linux/mm.h>
#include <linux/in.h>
#include <linux/init.h>
-#include <linux/brlock.h>
-LIST_HEAD(snap_list);
+static LIST_HEAD(snap_list);
+static spinlock_t snap_lock = SPIN_LOCK_UNLOCKED;
static struct llc_sap *snap_sap;
/*
@@ -34,17 +34,13 @@
struct list_head *entry;
struct datalink_proto *proto = NULL, *p;
- if (list_empty(&snap_list))
- goto out;
-
- list_for_each(entry, &snap_list) {
+ list_for_each_rcu(entry, &snap_list) {
p = list_entry(entry, struct datalink_proto, node);
if (!memcmp(p->type, desc, 5)) {
proto = p;
break;
}
}
-out:
return proto;
}
@@ -55,11 +51,13 @@
struct packet_type *pt)
{
int rc = 1;
- struct datalink_proto *proto = find_snap_client(skb->h.raw);
+ struct datalink_proto *proto;
static struct packet_type snap_packet_type = {
.type = __constant_htons(ETH_P_SNAP),
};
+ rcu_read_lock();
+ proto = find_snap_client(skb->h.raw);
if (proto) {
/* Pass the frame on. */
skb->h.raw += 5;
@@ -71,6 +69,7 @@
rc = 1;
}
+ rcu_read_unlock();
return rc;
}
@@ -124,7 +123,7 @@
{
struct datalink_proto *proto = NULL;
- br_write_lock_bh(BR_NETPROTO_LOCK);
+ spin_lock_bh(&snap_lock);
if (find_snap_client(desc))
goto out;
@@ -135,10 +134,12 @@
proto->rcvfunc = rcvfunc;
proto->header_length = 5 + 3; /* snap + 802.2 */
proto->request = snap_request;
- list_add(&proto->node, &snap_list);
+ list_add_rcu(&proto->node, &snap_list);
}
out:
- br_write_unlock_bh(BR_NETPROTO_LOCK);
+ spin_unlock_bh(&snap_lock);
+
+ synchronize_net();
return proto;
}
@@ -147,12 +148,13 @@
*/
void unregister_snap_client(struct datalink_proto *proto)
{
- br_write_lock_bh(BR_NETPROTO_LOCK);
+ spin_lock_bh(&snap_lock);
+ list_del_rcu(&proto->node);
+ spin_unlock_bh(&snap_lock);
- list_del(&proto->node);
- kfree(proto);
+ synchronize_net();
- br_write_unlock_bh(BR_NETPROTO_LOCK);
+ kfree(proto);
}
MODULE_LICENSE("GPL");
===================================================================
This BitKeeper patch contains the following changesets:
1.1170
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