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Message-ID: <4a959eec.ILZAXmwdAGY2H5to%dougthompson@xmission.com>
Date: Wed, 26 Aug 2009 14:45:32 -0600
From: dougthompson@...ssion.com
To: bluesmoke-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Subject: [PATCH 1/1] edac: core remove completion-wait for complete with
rcu_barrier
From: Jesper Dangaard Brouer <hawk@...x.dk>
Module edac_core.ko uses call_rcu() callbacks in edac_device.c, edac_mc.c
and edac_pci.c.
They all uses a wait_for_completion scheme, but this scheme it not 100%
safe on multiple CPUs. See the _rcu_barrier() implementation which explains
why extra precausion is needed.
The patch adds a comment about rcu_barrier() and as a precausion calls
rcu_barrier(). A maintainer needs to look at removing the wait_for_completion
code.
Maintainer Doug Thompson removed the wait_for_completion code
Signed-off-by Jesper Dangaard Brouer" <hawk@...x.dk>
Signed-off-by: Doug Thompson <dougthompson@...ssion.com>
---
Index: linux-2.6.31-rc7/drivers/edac/edac_device.c
===================================================================
--- linux-2.6.31-rc7.orig/drivers/edac/edac_device.c 2009-08-21 19:00:46.000000000 -0600
+++ linux-2.6.31-rc7/drivers/edac/edac_device.c 2009-08-26 14:39:00.000000000 -0600
@@ -356,7 +356,6 @@ static void complete_edac_device_list_de
edac_dev = container_of(head, struct edac_device_ctl_info, rcu);
INIT_LIST_HEAD(&edac_dev->link);
- complete(&edac_dev->removal_complete);
}
/*
@@ -369,10 +368,8 @@ static void del_edac_device_from_global_
*edac_device)
{
list_del_rcu(&edac_device->link);
-
- init_completion(&edac_device->removal_complete);
call_rcu(&edac_device->rcu, complete_edac_device_list_del);
- wait_for_completion(&edac_device->removal_complete);
+ rcu_barrier();
}
/*
Index: linux-2.6.31-rc7/drivers/edac/edac_mc.c
===================================================================
--- linux-2.6.31-rc7.orig/drivers/edac/edac_mc.c 2009-08-21 19:00:46.000000000 -0600
+++ linux-2.6.31-rc7/drivers/edac/edac_mc.c 2009-08-26 14:35:35.000000000 -0600
@@ -418,16 +418,14 @@ static void complete_mc_list_del(struct
mci = container_of(head, struct mem_ctl_info, rcu);
INIT_LIST_HEAD(&mci->link);
- complete(&mci->complete);
}
static void del_mc_from_global_list(struct mem_ctl_info *mci)
{
atomic_dec(&edac_handlers);
list_del_rcu(&mci->link);
- init_completion(&mci->complete);
call_rcu(&mci->rcu, complete_mc_list_del);
- wait_for_completion(&mci->complete);
+ rcu_barrier();
}
/**
Index: linux-2.6.31-rc7/drivers/edac/edac_pci.c
===================================================================
--- linux-2.6.31-rc7.orig/drivers/edac/edac_pci.c 2009-08-21 19:00:46.000000000 -0600
+++ linux-2.6.31-rc7/drivers/edac/edac_pci.c 2009-08-26 14:36:31.000000000 -0600
@@ -174,7 +174,6 @@ static void complete_edac_pci_list_del(s
pci = container_of(head, struct edac_pci_ctl_info, rcu);
INIT_LIST_HEAD(&pci->link);
- complete(&pci->complete);
}
/*
@@ -185,9 +184,8 @@ static void complete_edac_pci_list_del(s
static void del_edac_pci_from_global_list(struct edac_pci_ctl_info *pci)
{
list_del_rcu(&pci->link);
- init_completion(&pci->complete);
call_rcu(&pci->rcu, complete_edac_pci_list_del);
- wait_for_completion(&pci->complete);
+ rcu_barrier();
}
#if 0
--
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