Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=b34bd06e485abf5b24fc13a9a988ebf4d2915dd6
Commit: b34bd06e485abf5b24fc13a9a988ebf4d2915dd6
Parent: 7be77e20d59fc3dd3fdde31641e0bc821114d26b
Author: Paul E. McKenney <[EMAIL PROTECTED]>
AuthorDate: Tue Jul 31 00:38:48 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue Jul 31 15:39:40 2007 -0700
bpqether: fix rcu usage
The rcu_dereference() primitive needs to be applied to an l-value in order
to
ensure that compiler writers don't get an opportunity to apply reordering
optimizations that could result in multiple fetches or in other misbehavior.
This patch pulls the rcu_dereference() calls in bpq_seq_next() up to the
point
at which the fetched pointers are still l-values, rather than after
list_entry() has transformed them into r-values.
Signed-off-by: Paul E. McKenney <[EMAIL PROTECTED]>
Cc: Jeff Garzik <[EMAIL PROTECTED]>
Cc: Ralf Baechle <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
drivers/net/hamradio/bpqether.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/hamradio/bpqether.c b/drivers/net/hamradio/bpqether.c
index 656f278..cc0ee93 100644
--- a/drivers/net/hamradio/bpqether.c
+++ b/drivers/net/hamradio/bpqether.c
@@ -413,12 +413,12 @@ static void *bpq_seq_next(struct seq_file *seq, void *v,
loff_t *pos)
++*pos;
if (v == SEQ_START_TOKEN)
- p = bpq_devices.next;
+ p = rcu_dereference(bpq_devices.next);
else
- p = ((struct bpqdev *)v)->bpq_list.next;
+ p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next);
return (p == &bpq_devices) ? NULL
- : rcu_dereference(list_entry(p, struct bpqdev, bpq_list));
+ : list_entry(p, struct bpqdev, bpq_list);
}
static void bpq_seq_stop(struct seq_file *seq, void *v)
-
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