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authorJesper Dangaard Brouer <hawk@comx.dk>2009-09-23 15:57:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-24 07:21:05 -0700
commit458e5ff13e1bed050990d97e9aa55bcdafc951a7 (patch)
tree521d837beabe5265f070351a8ea42d48408ec5d7
parentdd8ef1db87a486577b3a76e6ad45df52e12d0145 (diff)
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>
-rw-r--r--drivers/edac/edac_device.c5
-rw-r--r--drivers/edac/edac_mc.c4
-rw-r--r--drivers/edac/edac_pci.c4
3 files changed, 3 insertions, 10 deletions
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index b02a6a69a8f0..d5e13c94714f 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -356,7 +356,6 @@ static void complete_edac_device_list_del(struct rcu_head *head)
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_list(struct edac_device_ctl_info
*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 335b7ebdb11c..b629c41756f0 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -418,16 +418,14 @@ static void complete_mc_list_del(struct rcu_head *head)
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 30b585b1d60b..efb5d5650783 100644
--- a/drivers/edac/edac_pci.c
+++ b/drivers/edac/edac_pci.c
@@ -174,7 +174,6 @@ static void complete_edac_pci_list_del(struct rcu_head *head)
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(struct rcu_head *head)
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