edac: core: remove completion-wait for complete with rcu_barrier
Module edac_core.ko uses call_rcu() callbacks in edac_device.c, edac_mc.c
and edac_pci.c.
They all use 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.
[dougthompson@xmission.com: remove the wait_for_completion code]
Signed-off-by Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index b02a6a6..d5e13c9 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -356,7 +356,6 @@
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 @@
*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();
}
/*
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 335b7eb..b629c41 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -418,16 +418,14 @@
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();
}
/**
diff --git a/drivers/edac/edac_pci.c b/drivers/edac/edac_pci.c
index 30b585b1..efb5d56 100644
--- a/drivers/edac/edac_pci.c
+++ b/drivers/edac/edac_pci.c
@@ -174,7 +174,6 @@
pci = container_of(head, struct edac_pci_ctl_info, rcu);
INIT_LIST_HEAD(&pci->link);
- complete(&pci->complete);
}
/*
@@ -185,9 +184,8 @@
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