net: mvneta: use buf->type to determine whether to dma-unmap

Now that we use a different buffer type for TSO headers, we can use
buf->type to determine whether the original buffer was DMA-mapped or
not. The rules are:

	MVNETA_TYPE_XDP_TX - from a DMA pool, no unmap is required
	MVNETA_TYPE_XDP_NDO - dma_map_single()'d
	MVNETA_TYPE_SKB - normal skbuff, dma_map_single()'d
	MVNETA_TYPE_TSO - from the TSO buffer area

This means we only need to call dma_unmap_single() on the XDP_NDO and
SKB types of buffer, and we no longer need the private IS_TSO_HEADER()
which relies on the TSO region being contiguously allocated.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/marvell/mvneta.c

@@ -364,10 +364,6 @@
 			 MVNETA_SKB_HEADROOM))
 #define MVNETA_MAX_RX_BUF_SIZE	(PAGE_SIZE - MVNETA_SKB_PAD)
 
-#define IS_TSO_HEADER(txq, addr) \
-	((addr >= txq->tso_hdrs_phys) && \
-	 (addr < txq->tso_hdrs_phys + txq->size * TSO_HEADER_SIZE))
-
 #define MVNETA_RX_GET_BM_POOL_ID(rxd) \
 	(((rxd)->status & MVNETA_RXD_BM_POOL_MASK) >> MVNETA_RXD_BM_POOL_SHIFT)
 
@@ -1879,8 +1875,8 @@ static void mvneta_txq_bufs_free(struct mvneta_port *pp,
 
 		mvneta_txq_inc_get(txq);
 
-		if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr) &&
-		    buf->type != MVNETA_TYPE_XDP_TX)
+		if (buf->type == MVNETA_TYPE_XDP_NDO ||
+		    buf->type == MVNETA_TYPE_SKB)
 			dma_unmap_single(pp->dev->dev.parent,
 					 tx_desc->buf_phys_addr,
 					 tx_desc->data_size, DMA_TO_DEVICE);
@@ -2728,8 +2724,9 @@ static void mvneta_release_descs(struct mvneta_port *pp,
 
 	for (i = num; i >= 0; i--) {
 		struct mvneta_tx_desc *tx_desc = txq->descs + desc_idx;
+		struct mvneta_tx_buf *buf = &txq->buf[desc_idx];
 
-		if (!IS_TSO_HEADER(txq, tx_desc->buf_phys_addr))
+		if (buf->type == MVNETA_TYPE_SKB)
 			dma_unmap_single(pp->dev->dev.parent,
 					 tx_desc->buf_phys_addr,
 					 tx_desc->data_size,