edac: core: remove completion-wait for complete with rcu_barrier

458e5ff1 · Jesper Dangaard Brouer <[email protected]> · 2009-09-23 15:57:29 -07:00

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.

[[email protected]: remove the wait_for_completion code]
Signed-off-by Jesper Dangaard Brouer <[email protected]>
Signed-off-by: Doug Thompson <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: 458e5ff13e1bed050990d97e9aa55bcdafc951a7
Parents: dd8ef1db

Changes

3 files changed · +3 −10

File	Status	Add	Del	Content
drivers/edac/edac_device.c	modified	+1	−4	View file
drivers/edac/edac_mc.c	modified	+1	−3	View file
drivers/edac/edac_pci.c	modified	+1	−3	View file

drivers/edac/edac_device.c

View file

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 @@ 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();
 }
 
 /*

drivers/edac/edac_mc.c

View file

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 @@ 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();
 }
 
 /**

drivers/edac/edac_pci.c

View file

diff --git a/drivers/edac/edac_pci.c b/drivers/edac/edac_pci.c
index 30b585b..efb5d56 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