sfc: Add support for reading packet length from prefix
Define a flag for struct efx_rx_buffer and efx_rx_packet() that
indicates packet length must be read from the prefix. If this
is set, read the length in __efx_rx_packet() (when the prefix
should have arrived in cache).
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 f52b38c..e85bed0 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -263,6 +263,7 @@
#define EFX_RX_PKT_CSUMMED 0x0002
#define EFX_RX_PKT_DISCARD 0x0004
#define EFX_RX_PKT_TCP 0x0040
+#define EFX_RX_PKT_PREFIX_LEN 0x0080 /* length is in prefix only */
/**
* struct efx_rx_page_state - Page-based rx buffer state
@@ -668,6 +669,8 @@
* @rx_prefix_size: Size of RX prefix before packet data
* @rx_packet_hash_offset: Offset of RX flow hash from start of packet data
* (valid only if @rx_prefix_size != 0; always negative)
+ * @rx_packet_len_offset: Offset of RX packet length from start of packet data
+ * (valid only for NICs that set %EFX_RX_PKT_PREFIX_LEN; always negative)
* @rx_hash_key: Toeplitz hash key for RSS
* @rx_indir_table: Indirection table for RSS
* @rx_scatter: Scatter mode enabled for receives
@@ -800,6 +803,7 @@
unsigned int rx_pages_per_batch;
unsigned int rx_prefix_size;
int rx_packet_hash_offset;
+ int rx_packet_len_offset;
u8 rx_hash_key[40];
u32 rx_indir_table[128];
bool rx_scatter;
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index 7646bb3..864b6ff 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -526,7 +526,8 @@
/* Validate the number of fragments and completed length */
if (n_frags == 1) {
- efx_rx_packet__check_len(rx_queue, rx_buf, len);
+ if (!(flags & EFX_RX_PKT_PREFIX_LEN))
+ efx_rx_packet__check_len(rx_queue, rx_buf, len);
} else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
unlikely(len <= (n_frags - 1) * EFX_RX_USR_BUF_SIZE) ||
unlikely(len > n_frags * EFX_RX_USR_BUF_SIZE) ||
@@ -554,7 +555,7 @@
return;
}
- if (n_frags == 1)
+ if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
rx_buf->len = len;
/* Release and/or sync the DMA mapping - assumes all RX buffers
@@ -633,6 +634,13 @@
efx_rx_buffer(&channel->rx_queue, channel->rx_pkt_index);
u8 *eh = efx_rx_buf_va(rx_buf);
+ /* Read length from the prefix if necessary. This already
+ * excludes the length of the prefix itself.
+ */
+ if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN)
+ rx_buf->len = le16_to_cpup((__le16 *)
+ (eh + efx->rx_packet_len_offset));
+
/* If we're in loopback test, then pass the packet directly to the
* loopback layer, and free the rx_buf here
*/