[PATCH] (2/5) Remvoe brlock from snap and vlan

From: Stephen Hemminger (shemminger@osdl.org)
Date: Thu Mar 13 2003 - 17:40:07 EST


Remove brlock from snap and vlan.

Change in snap unregister path from earlier version to use synchronize_kernel.

This code needs further testing before final 2.5 inclusion.
(Kind of wonder if anyone actually ever uses this?)

diff -urN -X dontdiff linux-2.5.64/net/802/psnap.c linux-2.5-nobrlock/net/802/psnap.c
--- linux-2.5.64/net/802/psnap.c 2003-03-11 09:08:01.000000000 -0800
+++ linux-2.5-nobrlock/net/802/psnap.c 2003-03-12 15:34:53.000000000 -0800
@@ -21,10 +21,10 @@
 #include <linux/mm.h>
 #include <linux/in.h>
 #include <linux/init.h>
-#include <linux/brlock.h>
 
 LIST_HEAD(snap_list);
 static struct llc_sap *snap_sap;
+static spinlock_t snap_lock = SPIN_LOCK_UNLOCKED;
 
 /*
  * Find a snap client by matching the 5 bytes.
@@ -34,17 +34,15 @@
         struct list_head *entry;
         struct datalink_proto *proto = NULL, *p;
 
- if (list_empty(&snap_list))
- goto out;
-
- list_for_each(entry, &snap_list) {
+ rcu_read_lock();
+ 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:
+ rcu_read_unlock();
         return proto;
 }
 
@@ -124,8 +122,7 @@
 {
         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 +132,10 @@
                 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);
         return proto;
 }
 
@@ -147,12 +144,13 @@
  */
 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);
+ synchronize_kernel(); /* wait for RCU */
         kfree(proto);
 
- br_write_unlock_bh(BR_NETPROTO_LOCK);
 }
 
 MODULE_LICENSE("GPL");
diff -urN -X dontdiff linux-2.5.64/net/8021q/vlan.c linux-2.5-nobrlock/net/8021q/vlan.c
--- linux-2.5.64/net/8021q/vlan.c 2003-03-11 09:08:01.000000000 -0800
+++ linux-2.5-nobrlock/net/8021q/vlan.c 2003-03-12 14:52:40.000000000 -0800
@@ -29,7 +29,6 @@
 #include <net/p8022.h>
 #include <net/arp.h>
 #include <linux/rtnetlink.h>
-#include <linux/brlock.h>
 #include <linux/notifier.h>
 
 #include <linux/if_vlan.h>
@@ -68,7 +67,6 @@
         .dev =NULL,
         .func = vlan_skb_recv, /* VLAN receive method */
         .data = (void *)(-1), /* Set here '(void *)1' when this code can SHARE SKBs */
- .next = NULL
 };
 
 /* End of global variables definitions. */
@@ -231,9 +229,11 @@
                                 real_dev->vlan_rx_kill_vid(real_dev, vlan_id);
                         }
 
- br_write_lock(BR_NETPROTO_LOCK);
                         grp->vlan_devices[vlan_id] = NULL;
- br_write_unlock(BR_NETPROTO_LOCK);
+
+ /* wait for RCU in network receive */
+ smp_wmb();
+ synchronize_kernel();
 
 
                         /* Caller unregisters (and if necessary, puts)
diff -urN -X dontdiff linux-2.5.64/net/8021q/vlan_dev.c linux-2.5-nobrlock/net/8021q/vlan_dev.c
--- linux-2.5.64/net/8021q/vlan_dev.c 2003-03-11 09:08:01.000000000 -0800
+++ linux-2.5-nobrlock/net/8021q/vlan_dev.c 2003-03-12 14:52:40.000000000 -0800
@@ -31,7 +31,6 @@
 #include <net/datalink.h>
 #include <net/p8022.h>
 #include <net/arp.h>
-#include <linux/brlock.h>
 
 #include "vlan.h"
 #include "vlanproc.h"

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sat Mar 15 2003 - 22:00:37 EST