sgi-xp: eliminate false detection of no heartbeat

158bc69e · Dean Nelson <[email protected]> · 2009-01-15 13:50:57 -08:00

After XPC has been up and running on multiple partitions for any length of
time, if XPC on one of the partitions is stopped and restarted (either by
a rmmod/insmod or a system restart), it is possible for the XPCs running
on the other partitions to falsely detect a lack of heartbeat from the XPC
that was just restarted.  This false detection will occur if the restarted
XPC comes up within the five-seconds preceding one of the other XPC's
heartbeat check (which occurs once every twenty seconds).

The detection of no heartbeat results in the detecting XPC deactivating
from the just restarted XPC.  The only remedy is to restart one of the
XPCs and hope that one doesn't hit this five-second window on any of the
other partitions.

Signed-off-by: Dean Nelson <[email protected]>
Signed-off-by: Robin Holt <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: 158bc69effbf96f59c01cdeb20f8d4c184e59f8e
Parents: cafa1d8b

Changes

1 files changed · +1 −1

File	Status	Add	Del	Content
drivers/misc/sgi-xp/xpc_sn2.c	modified	+1	−1	View file

drivers/misc/sgi-xp/xpc_sn2.c

View file

diff --git a/drivers/misc/sgi-xp/xpc_sn2.c b/drivers/misc/sgi-xp/xpc_sn2.c
index 73b7fb8..82fb995 100644
--- a/drivers/misc/sgi-xp/xpc_sn2.c
+++ b/drivers/misc/sgi-xp/xpc_sn2.c
@@ -899,7 +899,7 @@ xpc_update_partition_info_sn2(struct xpc_partition *part, u8 remote_rp_version,
 	dev_dbg(xpc_part, "  remote_vars_pa = 0x%016lx\n",
 		part_sn2->remote_vars_pa);
 
-	part->last_heartbeat = remote_vars->heartbeat;
+	part->last_heartbeat = remote_vars->heartbeat - 1;
 	dev_dbg(xpc_part, "  last_heartbeat = 0x%016lx\n",
 		part->last_heartbeat);
 