ibm emac: Fix locking for enable/disable eob irq

Calls to mal_enable_eob_irq perform a read-write-modify of a dcr to
enable device irqs which is protected by a spin lock. However calls to
mal_disable_eob_irq do not take the corresponding lock.

This patch resolves the problem by ensuring that calls to
mal_disable_eob_irq also take the lock.

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/net/ethernet/ibm/emac/mal.c b/drivers/net/ethernet/ibm/emac/mal.c
index 909f9b6698b5..e7847510eda2 100644
--- a/drivers/net/ethernet/ibm/emac/mal.c
+++ b/drivers/net/ethernet/ibm/emac/mal.c
@@ -263,7 +263,9 @@ static inline void mal_schedule_poll(struct mal_instance *mal)
 {
         if (likely(napi_schedule_prep(&mal->napi))) {
                 MAL_DBG2(mal, "schedule_poll" NL);
+                spin_lock(&mal->lock);
                 mal_disable_eob_irq(mal);
+                spin_unlock(&mal->lock);
                 __napi_schedule(&mal->napi);
         } else
                 MAL_DBG2(mal, "already in poll" NL);
@@ -445,7 +447,9 @@ static int mal_poll(struct napi_struct *napi, int budget)
                         if (!napi_reschedule(napi))
                                 goto more_work;
 
+                        spin_lock_irqsave(&mal->lock, flags);
                         mal_disable_eob_irq(mal);
+                        spin_unlock_irqrestore(&mal->lock, flags);
                         goto again;
                 }
                 mc->ops->poll_tx(mc->dev);