spidernet: transmit race
Multiple threads performing a transmit can race into
the spidernet tx ring cleanup code. This puts the
relevant check under a lock.
Signed-off-by: Linas Vepstas <lins@austin.ibm.com>
Cc: Jens Osterkamp <Jens.Osterkamp@de.ibm.com>
Cc: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/spider_net.c b/drivers/net/spider_net.c
index 15b0bca..653a91a 100644
--- a/drivers/net/spider_net.c
+++ b/drivers/net/spider_net.c
@@ -803,8 +803,12 @@
unsigned long flags;
int status;
- while (chain->tail != chain->head) {
+ while (1) {
spin_lock_irqsave(&chain->lock, flags);
+ if (chain->tail == chain->head) {
+ spin_unlock_irqrestore(&chain->lock, flags);
+ return 0;
+ }
descr = chain->tail;
hwdescr = descr->hwdescr;