sfc: Refactor struct efx_tx_buffer to use a flags field
Add a flags field to struct efx_tx_buffer, replacing the
continuation and map_single booleans.
Since a single descriptor cannot be both a TSO header and the last
descriptor for an skb, unionise efx_tx_buffer::{skb,tsoh} and add
flags for validity of these fields.
Clear all flags in free buffers (whereas previously the continuation
flag would be set).
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index cd9c0a9..0ac01fa 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -91,29 +91,30 @@
};
/**
- * struct efx_tx_buffer - An Efx TX buffer
- * @skb: The associated socket buffer.
- * Set only on the final fragment of a packet; %NULL for all other
- * fragments. When this fragment completes, then we can free this
- * skb.
- * @tsoh: The associated TSO header structure, or %NULL if this
- * buffer is not a TSO header.
+ * struct efx_tx_buffer - buffer state for a TX descriptor
+ * @skb: When @flags & %EFX_TX_BUF_SKB, the associated socket buffer to be
+ * freed when descriptor completes
+ * @tsoh: When @flags & %EFX_TX_BUF_TSOH, the associated TSO header structure.
* @dma_addr: DMA address of the fragment.
+ * @flags: Flags for allocation and DMA mapping type
* @len: Length of this fragment.
* 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 dma_unmap_single should be used.
* @unmap_len: Length of this fragment to unmap
*/
struct efx_tx_buffer {
- const struct sk_buff *skb;
- struct efx_tso_header *tsoh;
+ union {
+ const struct sk_buff *skb;
+ struct efx_tso_header *tsoh;
+ };
dma_addr_t dma_addr;
+ unsigned short flags;
unsigned short len;
- bool continuation;
- bool unmap_single;
unsigned short unmap_len;
};
+#define EFX_TX_BUF_CONT 1 /* not last descriptor of packet */
+#define EFX_TX_BUF_SKB 2 /* buffer is last part of skb */
+#define EFX_TX_BUF_TSOH 4 /* buffer is TSO header */
+#define EFX_TX_BUF_MAP_SINGLE 8 /* buffer was mapped with dma_map_single() */
/**
* struct efx_tx_queue - An Efx TX queue