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Date:      Wed, 1 Sep 2010 19:22:19 +0000 (UTC)
From:      Attilio Rao <attilio@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-projects@freebsd.org
Subject:   svn commit: r212106 - in projects/sv/sys: net netinet
Message-ID:  <201009011922.o81JMJFh077539@svn.freebsd.org>
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Author: attilio
Date: Wed Sep  1 19:22:19 2010
New Revision: 212106
URL: http://svn.freebsd.org/changeset/base/212106

Log:
  The break lock happens while the system panicked but it is not an useful
  operation as, at that point, the other CPUs might be already stopped.
  It is more correct to just skip locking entirely for the interfaces,
  as long as the asserts won't whine in panicstr != NULL conditions (to
  be added asap).
  The 'acquire_lock' and 'release_lock' semantic is just left for the
  normal RB_DUMP reboot(2) invokation case (reboot -d, for example).
  
  Discussed with:	emaste, rstone

Modified:
  projects/sv/sys/net/netdump_client.c
  projects/sv/sys/netinet/netdump.h

Modified: projects/sv/sys/net/netdump_client.c
==============================================================================
--- projects/sv/sys/net/netdump_client.c	Wed Sep  1 18:41:59 2010	(r212105)
+++ projects/sv/sys/net/netdump_client.c	Wed Sep  1 19:22:19 2010	(r212106)
@@ -1153,8 +1153,6 @@ static void
 netdump_trigger(void *arg, int howto)
 {
 	struct dumperinfo dumper;
-	int broke_lock = 0;
-	uint8_t broken_state[NETDUMP_BROKEN_STATE_BUFFER_SIZE];
 	void (*old_if_input)(struct ifnet *, struct mbuf *)=NULL;
 	int error;
 
@@ -1188,8 +1186,7 @@ netdump_trigger(void *arg, int howto)
 	savectx(&dumppcb);
 	dumping++;
 
-	bzero(broken_state, sizeof(broken_state));
-	error = nd_nic->if_netdump->break_lock(nd_nic, &broke_lock, broken_state, sizeof(broken_state));
+	error = nd_nic->if_netdump->acquire_lock(nd_nic);
 
 	if(error) {
 		printf("netdump_trigger: Could not acquire lock on %s\n", nd_nic->if_xname);
@@ -1256,50 +1253,6 @@ trig_abort:
 }
 
 /*-
- * Public primitives.
- */
-
-/* this isn't declared in any header file... */
-extern int system_panic;
-
-int
-netdump_break_lock(struct mtx *lock, const char *name, int *broke_lock,
-    uint8_t *broken_state, u_int index, u_int bstatesz)
-{
-	/* XXX: Technically this might be bad because it's possible to be called
-	   from within a critical section (such as when the software watchdog
-	   triggers), although it's only a trylock */
-	if (!mtx_trylock(lock)) {
-		if(system_panic) {
-			/* The lock is already held. Attempting to use the card is
-			 * probably unsafe at this point, but since we're panicking
-			 * anyway, there's nothing to lose. Be horrible and break the
-			 * lock. 
-			 */
-			critical_enter(); /* No interrupts so that this is less likely
-			                   * to mess up 
-			                   */
-			if(bstatesz >= (index + sizeof(*lock))) {
-				bcopy(lock, broken_state + index, sizeof(*lock));
-			} else {
-				printf("Netdump: cannot save state of lock %s!", name);
-			}
-
-			_release_lock_quick(lock);
-			mtx_destroy(lock);
-			mtx_init(lock, name, MTX_NETWORK_LOCK,
-				MTX_DEF);
-			*broke_lock = 1;
-			critical_exit();/* We can't grab a lock in a critical section */
-			mtx_lock(lock);
-		} else {
-			return EAGAIN;
-		}
-	} 
-	return 0;
-}
-
-/*-
  * KLD specific code.
  */
 

Modified: projects/sv/sys/netinet/netdump.h
==============================================================================
--- projects/sv/sys/netinet/netdump.h	Wed Sep  1 18:41:59 2010	(r212105)
+++ projects/sv/sys/netinet/netdump.h	Wed Sep  1 19:22:19 2010	(r212106)
@@ -61,19 +61,13 @@ struct netdump_msg {
 
 #ifdef _KERNEL
 
-struct mtx;
-
 struct netdump_methods {
 	void	(*test_get_lock)(struct ifnet *);
-	int	(*break_lock)(struct ifnet *, int *, uint8_t *, u_int);
+	void	(*acquire_lock)(struct ifnet *);
 	void	(*release_lock)(struct ifnet *);
 	int	(*poll_locked)(struct ifnet *, enum poll_cmd, int);
 };
 
-int	 netdump_break_lock(struct mtx *lock, const char *name,
-	    int *broke_lock, uint8_t *broken_state, u_int index,
-	    u_int bstatesz);
-
 #endif
 
 #endif /* !_NETINET_NETDUMP_H_ */
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