[TG3]: Fix missing memory barriers and SD_STATUS_UPDATED bit clearing.

There must be a rmb() between reading the status block tag
and calling tg3_has_work().  This was missing in tg3_mis()
and tg3_interrupt_tagged().  tg3_poll() got it right.

Also, SD_STATUS_UPDATED must be cleared in the status block
right before we call tg3_has_work().  Only tg3_poll() got this
wrong.

Based upon patches and commentary from Grant Grundler and
Michael Chan.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index a0b8848049c9..fef1d087107c 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -2929,6 +2929,7 @@ static int tg3_poll(struct net_device *netdev, int *budget)
         if (tp->tg3_flags & TG3_FLAG_TAGGED_STATUS)
                 tp->last_tag = sblk->status_tag;
         rmb();
+        sblk->status &= ~SD_STATUS_UPDATED;
 
         /* if no more work, tell net stack and NIC we're done */
         done = !tg3_has_work(tp);
@@ -2964,6 +2965,7 @@ static irqreturn_t tg3_msi(int irq, void *dev_id, struct pt_regs *regs)
          */
         tw32_mailbox(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW, 0x00000001);
         tp->last_tag = sblk->status_tag;
+        rmb();
         sblk->status &= ~SD_STATUS_UPDATED;
         if (likely(tg3_has_work(tp)))
                 netif_rx_schedule(dev);         /* schedule NAPI poll */
@@ -3051,6 +3053,7 @@ static irqreturn_t tg3_interrupt_tagged(int irq, void *dev_id, struct pt_regs *r
                 tw32_mailbox(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW,
                              0x00000001);
                 tp->last_tag = sblk->status_tag;
+                rmb();
                 sblk->status &= ~SD_STATUS_UPDATED;
                 if (likely(tg3_has_work(tp)))
                         netif_rx_schedule(dev);         /* schedule NAPI poll */