sfc: Reduce the size of struct efx_tx_buffer

Remove unmap_addr since it can be calculated from dma_addr, len and
unmap_len.  This saves 4-16 bytes.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 11 insertions, 11 deletions

diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index f539e2e0da1b..6369f9253c7b 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -130,7 +130,6 @@ struct efx_special_buffer {
  *      This field is zero when the queue slot is empty.
  * @continuation: True if this fragment is not the end of a packet.
  * @unmap_single: True if pci_unmap_single should be used.
- * @unmap_addr: DMA address to unmap
  * @unmap_len: Length of this fragment to unmap
  */
 struct efx_tx_buffer {
@@ -140,7 +139,6 @@ struct efx_tx_buffer {
         unsigned short len;
         unsigned char continuation;
         unsigned char unmap_single;
-        dma_addr_t unmap_addr;
         unsigned short unmap_len;
 };
 
diff --git a/drivers/net/sfc/tx.c b/drivers/net/sfc/tx.c
index 11127757c05d..5f01371baaf9 100644
--- a/drivers/net/sfc/tx.c
+++ b/drivers/net/sfc/tx.c
@@ -64,12 +64,14 @@ static inline void efx_dequeue_buffer(struct efx_tx_queue *tx_queue,
 {
         if (buffer->unmap_len) {
                 struct pci_dev *pci_dev = tx_queue->efx->pci_dev;
+                dma_addr_t unmap_addr = (buffer->dma_addr + buffer->len -
+                                         buffer->unmap_len);
                 if (buffer->unmap_single)
-                        pci_unmap_single(pci_dev, buffer->unmap_addr,
-                                         buffer->unmap_len, PCI_DMA_TODEVICE);
+                        pci_unmap_single(pci_dev, unmap_addr, buffer->unmap_len,
+                                         PCI_DMA_TODEVICE);
                 else
-                        pci_unmap_page(pci_dev, buffer->unmap_addr,
-                                       buffer->unmap_len, PCI_DMA_TODEVICE);
+                        pci_unmap_page(pci_dev, unmap_addr, buffer->unmap_len,
+                                       PCI_DMA_TODEVICE);
                 buffer->unmap_len = 0;
                 buffer->unmap_single = 0;
         }
@@ -233,7 +235,6 @@ static inline int efx_enqueue_skb(struct efx_tx_queue *tx_queue,
                 } while (len);
 
                 /* Transfer ownership of the unmapping to the final buffer */
-                buffer->unmap_addr = unmap_addr;
                 buffer->unmap_single = unmap_single;
                 buffer->unmap_len = unmap_len;
                 unmap_len = 0;
@@ -805,6 +806,7 @@ static inline void efx_tso_put_header(struct efx_tx_queue *tx_queue,
 static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
 {
         struct efx_tx_buffer *buffer;
+        dma_addr_t unmap_addr;
 
         /* Work backwards until we hit the original insert pointer value */
         while (tx_queue->insert_count != tx_queue->write_count) {
@@ -816,15 +818,15 @@ static void efx_enqueue_unwind(struct efx_tx_queue *tx_queue)
                 buffer->len = 0;
                 buffer->continuation = 1;
                 if (buffer->unmap_len) {
+                        unmap_addr = (buffer->dma_addr + buffer->len -
+                                      buffer->unmap_len);
                         if (buffer->unmap_single)
                                 pci_unmap_single(tx_queue->efx->pci_dev,
-                                                 buffer->unmap_addr,
-                                                 buffer->unmap_len,
+                                                 unmap_addr, buffer->unmap_len,
                                                  PCI_DMA_TODEVICE);
                         else
                                 pci_unmap_page(tx_queue->efx->pci_dev,
-                                               buffer->unmap_addr,
-                                               buffer->unmap_len,
+                                               unmap_addr, buffer->unmap_len,
                                                PCI_DMA_TODEVICE);
                         buffer->unmap_len = 0;
                 }