On 06.01.2017 09:06, Alexander Loktionov wrote:
From: David VomLehn <voml...@texas.net>

Add code to support the transmit and receive ring buffers.

Signed-off-by: Alexander Loktionov <alexander.loktio...@aquantia.com>
Signed-off-by: Dmitrii Tarakanov <dmitrii.taraka...@aquantia.com>
Signed-off-by: Pavel Belous <pavel.bel...@aquantia.com>
Signed-off-by: David M. VomLehn <voml...@texas.net>
---
  drivers/net/ethernet/aquantia/aq_ring.c | 380 ++++++++++++++++++++++++++++++++
  drivers/net/ethernet/aquantia/aq_ring.h | 147 ++++++++++++
  2 files changed, 527 insertions(+)
  create mode 100644 drivers/net/ethernet/aquantia/aq_ring.c
  create mode 100644 drivers/net/ethernet/aquantia/aq_ring.h

diff --git a/drivers/net/ethernet/aquantia/aq_ring.c 
b/drivers/net/ethernet/aquantia/aq_ring.c
new file mode 100644
index 0000000..a7ef6aa
--- /dev/null
+++ b/drivers/net/ethernet/aquantia/aq_ring.c
@@ -0,0 +1,380 @@
+/*
+ * aQuantia Corporation Network Driver
+ * Copyright (C) 2014-2016 aQuantia Corporation. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ */
+
+/* File aq_pci_ring.c: Definition of functions for Rx/Tx rings. */
+
+#include "aq_ring.h"
+#include "aq_nic.h"
+#include "aq_hw.h"
+
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+
+static struct aq_ring_s *aq_ring_alloc(struct aq_ring_s *self,
+                                      struct aq_nic_s *aq_nic,
+                                      struct aq_nic_cfg_s *aq_nic_cfg)
+{
+       int err = 0;
+
+       if (!self) {
+               err = -ENOMEM;
+               goto err_exit;
+       }

Why do you check this parameter but not the others?
Beside this since the function is static the only caller is your own code, so why is a check needed at all? Can self ever be NULL? Same pattern occurs in several other functions.
+
+struct aq_ring_s *aq_ring_tx_alloc(struct aq_ring_s *self,
+                                  struct aq_nic_s *aq_nic,
+                                  unsigned int idx,
+                                  struct aq_nic_cfg_s *aq_nic_cfg)

+
+struct aq_ring_s *aq_ring_rx_alloc(struct aq_ring_s *self,
+                                  struct aq_nic_s *aq_nic,
+                                  unsigned int idx,
+                                  struct aq_nic_cfg_s *aq_nic_cfg)
+{
+       int err = 0;
+
+       if (!self) {
+               err = -ENOMEM;
+               goto err_exit;

+
+void aq_ring_free(struct aq_ring_s *self)
+{
+       if (!self)
+               goto err_exit;
+
+       kfree(self->buff_ring);
+
+       if (self->dx_ring)
+               dma_free_coherent(aq_nic_get_dev(self->aq_nic),
+                                 self->size * self->dx_size, self->dx_ring,
+                                 self->dx_ring_pa);
+
+err_exit:;
+}

This does not make sense. Just return immediately if "self" is NULL (and if you really have to make
 this check).
+
+int aq_ring_rx_clean(struct aq_ring_s *self, int *work_done, int budget)
+{
+       struct net_device *ndev = aq_nic_get_ndev(self->aq_nic);
+       int err = 0;
+       bool is_rsc_completed = true;
+
+       for (; (self->sw_head != self->hw_head) && budget;
+               self->sw_head = aq_ring_next_dx(self, self->sw_head),
+               --budget, ++(*work_done)) {
+               struct aq_ring_buff_s *buff = &self->buff_ring[self->sw_head];
+               struct sk_buff *skb = NULL;
+               unsigned int next_ = 0U;
+               unsigned int i = 0U;
+               struct aq_ring_buff_s *buff_ = NULL;
+
+               if (buff->is_error) {
+                       __free_pages(buff->page, 0);
+                       continue;
+               }
+
+               if (buff->is_cleaned)
+                       continue;
+
+               ++self->stats.rx_packets;
+               ++ndev->stats.rx_packets;
+               ndev->stats.rx_bytes += buff->len;
+
+               if (!buff->is_eop) {
+                       for (next_ = buff->next,
+                            buff_ = &self->buff_ring[next_]; true;
+                            next_ = buff_->next,
+                            buff_ = &self->buff_ring[next_]) {
+                               is_rsc_completed =
+                                       aq_ring_dx_in_range(self->sw_head,
+                                                           next_,
+                                                           self->hw_head);
+
+                               if (unlikely(!is_rsc_completed)) {
+                                       is_rsc_completed = false;
+                                       break;
+                               }
+
+                               if (buff_->is_eop)
+                                       break;
+                       }
+
+                       if (!is_rsc_completed) {
+                               err = 0;
+                               goto err_exit;
+                       }
+               }
+
+               skb = netdev_alloc_skb(ndev, ETH_HLEN + AQ_CFG_IP_ALIGN);
+
+               skb_reserve(skb, AQ_CFG_IP_ALIGN);

netdev_alloc_skb_ip_align() will do the proper alignment for you (BTW. AQ_CFG_IP_ALIGN is defined as 0 in aq_cfg.h.
Is this on purpose?)

+               skb_put(skb, ETH_HLEN);
+               memcpy(skb->data, page_address(buff->page), ETH_HLEN);
+
+               skb_add_rx_frag(skb, 0, buff->page, ETH_HLEN,
+                               buff->len - ETH_HLEN,
+                               SKB_TRUESIZE(buff->len - ETH_HLEN));
+               if (!buff->is_eop) {
+                       for (i = 1U, next_ = buff->next,
+                            buff_ = &self->buff_ring[next_]; true;
+                            next_ = buff_->next,
+                            buff_ = &self->buff_ring[next_], ++i) {
+                               skb_add_rx_frag(skb, i, buff_->page, 0,
+                                               buff_->len,
+                                               SKB_TRUESIZE(buff->len -
+                                               ETH_HLEN));
+                               buff_->is_cleaned = 1;
+
+                               if (buff_->is_eop)
+                                       break;
+                       }
+               }
+
+               skb->dev = ndev;
This is unnecessary. The following call of eth_type_trans() will do this already.

Regards,
Lino

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