ibmvnic: Unmap DMA address of TX descriptor buffers after use

There's no need to wait until a completion is received to unmap
TX descriptor buffers that have been passed to the hypervisor.
Instead unmap it when the hypervisor call has completed. This patch
avoids the possibility that a buffer will not be unmapped because
a TX completion is lost or mishandled.

Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Tested-by: Devesh K. Singh <devesh_singh@in.ibm.com>
Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 3da6800732656477bd5d932373dde23d1b4dde9c..cebd20f3128d4a6c6344c94b80496875e091d8d7 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1568,6 +1568,8 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
                lpar_rc = send_subcrq_indirect(adapter, handle_array[queue_num],
                                               (u64)tx_buff->indir_dma,
                                               (u64)num_entries);
+               dma_unmap_single(dev, tx_buff->indir_dma,
+                                sizeof(tx_buff->indir_arr), DMA_TO_DEVICE);
        } else {
                tx_buff->num_entries = num_entries;
                lpar_rc = send_subcrq(adapter, handle_array[queue_num],
@@ -2788,7 +2790,6 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
        union sub_crq *next;
        int index;
        int i, j;
-       u8 *first;
 
 restart_loop:
        while (pending_scrq(adapter, scrq)) {
@@ -2818,14 +2819,6 @@ restart_loop:
 
                                txbuff->data_dma[j] = 0;
                        }
-                       /* if sub_crq was sent indirectly */
-                       first = &txbuff->indir_arr[0].generic.first;
-                       if (*first == IBMVNIC_CRQ_CMD) {
-                               dma_unmap_single(dev, txbuff->indir_dma,
-                                                sizeof(txbuff->indir_arr),
-                                                DMA_TO_DEVICE);
-                               *first = 0;
-                       }
 
                        if (txbuff->last_frag) {
                                dev_kfree_skb_any(txbuff->skb);