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>
This commit is contained in:
Jesper Dangaard Brouer
2009-09-23 15:57:29 -07:00
committed by Linus Torvalds
parent dd8ef1db87
commit 458e5ff13e
3 changed files with 3 additions and 10 deletions
+1 -3
View File
@@ -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