The patch titled
edac: core: remove completion-wait for complete with rcu_barrier
has been added to the -mm tree. Its filename is
edac-core-remove-completion-wait-for-complete-with-rcu_barrier.patch
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------------------------------------------------------
Subject: edac: core: remove completion-wait for complete with rcu_barrier
From: Jesper Dangaard Brouer <hawk@xxxxxxx>
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@xxxxxxxxxxxx: remove the wait_for_completion code]
Signed-off-by Jesper Dangaard Brouer <hawk@xxxxxxx>
Signed-off-by: Doug Thompson <dougthompson@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/edac/edac_device.c | 5 +----
drivers/edac/edac_mc.c | 4 +---
drivers/edac/edac_pci.c | 4 +---
3 files changed, 3 insertions(+), 10 deletions(-)
diff -puN drivers/edac/edac_device.c~edac-core-remove-completion-wait-for-complete-with-rcu_barrier drivers/edac/edac_device.c
--- a/drivers/edac/edac_device.c~edac-core-remove-completion-wait-for-complete-with-rcu_barrier
+++ a/drivers/edac/edac_device.c
@@ -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();
}
/*
diff -puN drivers/edac/edac_mc.c~edac-core-remove-completion-wait-for-complete-with-rcu_barrier drivers/edac/edac_mc.c
--- a/drivers/edac/edac_mc.c~edac-core-remove-completion-wait-for-complete-with-rcu_barrier
+++ a/drivers/edac/edac_mc.c
@@ -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();
}
/**
diff -puN drivers/edac/edac_pci.c~edac-core-remove-completion-wait-for-complete-with-rcu_barrier drivers/edac/edac_pci.c
--- a/drivers/edac/edac_pci.c~edac-core-remove-completion-wait-for-complete-with-rcu_barrier
+++ a/drivers/edac/edac_pci.c
@@ -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
_
Patches currently in -mm which might be from hawk@xxxxxxx are
linux-next.patch
edac-core-remove-completion-wait-for-complete-with-rcu_barrier.patch
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