[dpdk-dev] [PATCH 07/36] net/sfc: check vs maximum number of Rx scatter buffers

[Andrew Rybchenko <arybchenko@solarflare.com>]

From: Igor Romanov <igor.romanov@oktetlabs.ru>

Update generic code to check that MTU and Rx buffer sizes
do not result in more Rx scatter segments than NIC can make.

Signed-off-by: Igor Romanov <igor.romanov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
 drivers/net/sfc/sfc_ethdev.c |  3 ++-
 drivers/net/sfc/sfc_rx.c     | 17 ++++++++++++++---
 drivers/net/sfc/sfc_rx.h     |  1 +
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/net/sfc/sfc_ethdev.c b/drivers/net/sfc/sfc_ethdev.c
index f41d0f5fe2..ca1b99a00f 100644
--- a/drivers/net/sfc/sfc_ethdev.c
+++ b/drivers/net/sfc/sfc_ethdev.c
@@ -954,7 +954,8 @@ sfc_check_scatter_on_all_rx_queues(struct sfc_adapter *sa, size_t pdu)
 
 		if (!sfc_rx_check_scatter(pdu, sa->rxq_ctrl[i].buf_size,
 					  encp->enc_rx_prefix_size,
-					  scatter_enabled, &error)) {
+					  scatter_enabled,
+					  encp->enc_rx_scatter_max, &error)) {
 			sfc_err(sa, "MTU check for RxQ %u failed: %s", i,
 				error);
 			return EINVAL;
diff --git a/drivers/net/sfc/sfc_rx.c b/drivers/net/sfc/sfc_rx.c
index 3e5c8e42da..7c50fe58b8 100644
--- a/drivers/net/sfc/sfc_rx.c
+++ b/drivers/net/sfc/sfc_rx.c
@@ -378,10 +378,20 @@ sfc_efx_rx_qdesc_status(struct sfc_dp_rxq *dp_rxq, uint16_t offset)
 
 boolean_t
 sfc_rx_check_scatter(size_t pdu, size_t rx_buf_size, uint32_t rx_prefix_size,
-		     boolean_t rx_scatter_enabled, const char **error)
+		     boolean_t rx_scatter_enabled, uint32_t rx_scatter_max,
+		     const char **error)
 {
-	if ((rx_buf_size < pdu + rx_prefix_size) && !rx_scatter_enabled) {
-		*error = "Rx scatter is disabled and RxQ mbuf pool object size is too small";
+	uint32_t effective_rx_scatter_max;
+	uint32_t rx_scatter_bufs;
+
+	effective_rx_scatter_max = rx_scatter_enabled ? rx_scatter_max : 1;
+	rx_scatter_bufs = EFX_DIV_ROUND_UP(pdu + rx_prefix_size, rx_buf_size);
+
+	if (rx_scatter_bufs > effective_rx_scatter_max) {
+		if (rx_scatter_enabled)
+			*error = "Possible number of Rx scatter buffers exceeds maximum number";
+		else
+			*error = "Rx scatter is disabled and RxQ mbuf pool object size is too small";
 		return B_FALSE;
 	}
 
@@ -1084,6 +1094,7 @@ sfc_rx_qinit(struct sfc_adapter *sa, unsigned int sw_index,
 	if (!sfc_rx_check_scatter(sa->port.pdu, buf_size,
 				  encp->enc_rx_prefix_size,
 				  (offloads & DEV_RX_OFFLOAD_SCATTER),
+				  encp->enc_rx_scatter_max,
 				  &error)) {
 		sfc_err(sa, "RxQ %u MTU check failed: %s", sw_index, error);
 		sfc_err(sa, "RxQ %u calculated Rx buffer size is %u vs "
diff --git a/drivers/net/sfc/sfc_rx.h b/drivers/net/sfc/sfc_rx.h
index b0b5327a49..d6ee9cf802 100644
--- a/drivers/net/sfc/sfc_rx.h
+++ b/drivers/net/sfc/sfc_rx.h
@@ -147,6 +147,7 @@ uint64_t sfc_rx_hf_efx_to_rte(struct sfc_rss *rss, efx_rx_hash_type_t efx);
 boolean_t sfc_rx_check_scatter(size_t pdu, size_t rx_buf_size,
 			       uint32_t rx_prefix_size,
 			       boolean_t rx_scatter_enabled,
+			       uint32_t rx_scatter_max,
 			       const char **error);
 
 #ifdef __cplusplus
-- 
2.17.1