e100: Use dma_rmb/wmb where appropriate

Reduce the CPU overhead for transmit and receive by using lightweight dma_
barriers instead of full barriers where they are applicable.

Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/intel/e100.c b/drivers/net/ethernet/intel/e100.c
index 05f88394f9a5599dcc1a4076a05694e596e6fdbe..1a450f4b6b125d2234ea159022666b5ca381d328 100644 (file)
--- a/drivers/net/ethernet/intel/e100.c
+++ b/drivers/net/ethernet/intel/e100.c
@@ -899,7 +899,7 @@ static int e100_exec_cb(struct nic *nic, struct sk_buff *skb,
        /* Order is important otherwise we'll be in a race with h/w:
         * set S-bit in current first, then clear S-bit in previous. */
        cb->command |= cpu_to_le16(cb_s);
-       wmb();
+       dma_wmb();
        cb->prev->command &= cpu_to_le16(~cb_s);
 
        while (nic->cb_to_send != nic->cb_to_use) {
@@ -1843,7 +1843,7 @@ static int e100_tx_clean(struct nic *nic)
        for (cb = nic->cb_to_clean;
            cb->status & cpu_to_le16(cb_complete);
            cb = nic->cb_to_clean = cb->next) {
-               rmb(); /* read skb after status */
+               dma_rmb(); /* read skb after status */
                netif_printk(nic, tx_done, KERN_DEBUG, nic->netdev,
                             "cb[%d]->status = 0x%04X\n",
                             (int)(((void*)cb - (void*)nic->cbs)/sizeof(struct cb)),
@@ -1993,7 +1993,7 @@ static int e100_rx_indicate(struct nic *nic, struct rx *rx,
 
        netif_printk(nic, rx_status, KERN_DEBUG, nic->netdev,
                     "status=0x%04X\n", rfd_status);
-       rmb(); /* read size after status bit */
+       dma_rmb(); /* read size after status bit */
 
        /* If data isn't ready, nothing to indicate */
        if (unlikely(!(rfd_status & cb_complete))) {