1 files changed, 749 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
new file mode 100644
index 000000000000..62e43649466e
--- /dev/null
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -0,0 +1,749 @@
+/****************************************************************************
+ * Driver for Solarflare Solarstorm network controllers and boards
+ * Copyright 2005-2006 Fen Systems Ltd.
+ * Copyright 2005-2011 Solarflare Communications Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation, incorporated herein by reference.
+ */
+
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/slab.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/prefetch.h>
+#include <net/ip.h>
+#include <net/checksum.h>
+#include "net_driver.h"
+#include "efx.h"
+#include "nic.h"
+#include "selftest.h"
+#include "workarounds.h"
+
+/* Number of RX descriptors pushed at once. */
+#define EFX_RX_BATCH  8
+
+/* Maximum size of a buffer sharing a page */
+#define EFX_RX_HALF_PAGE ((PAGE_SIZE >> 1) - sizeof(struct efx_rx_page_state))
+
+/* Size of buffer allocated for skb header area. */
+#define EFX_SKB_HEADERS  64u
+
+/*
+ * rx_alloc_method - RX buffer allocation method
+ *
+ * This driver supports two methods for allocating and using RX buffers:
+ * each RX buffer may be backed by an skb or by an order-n page.
+ *
+ * When GRO is in use then the second method has a lower overhead,
+ * since we don't have to allocate then free skbs on reassembled frames.
+ *
+ * Values:
+ *   - RX_ALLOC_METHOD_AUTO = 0
+ *   - RX_ALLOC_METHOD_SKB  = 1
+ *   - RX_ALLOC_METHOD_PAGE = 2
+ *
+ * The heuristic for %RX_ALLOC_METHOD_AUTO is a simple hysteresis count
+ * controlled by the parameters below.
+ *
+ *   - Since pushing and popping descriptors are separated by the rx_queue
+ *     size, so the watermarks should be ~rxd_size.
+ *   - The performance win by using page-based allocation for GRO is less
+ *     than the performance hit of using page-based allocation of non-GRO,
+ *     so the watermarks should reflect this.
+ *
+ * Per channel we maintain a single variable, updated by each channel:
+ *
+ *   rx_alloc_level += (gro_performed ? RX_ALLOC_FACTOR_GRO :
+ *                      RX_ALLOC_FACTOR_SKB)
+ * Per NAPI poll interval, we constrain rx_alloc_level to 0..MAX (which
+ * limits the hysteresis), and update the allocation strategy:
+ *
+ *   rx_alloc_method = (rx_alloc_level > RX_ALLOC_LEVEL_GRO ?
+ *                      RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB)
+ */
+static int rx_alloc_method = RX_ALLOC_METHOD_AUTO;
+
+#define RX_ALLOC_LEVEL_GRO 0x2000
+#define RX_ALLOC_LEVEL_MAX 0x3000
+#define RX_ALLOC_FACTOR_GRO 1
+#define RX_ALLOC_FACTOR_SKB (-2)
+
+/* This is the percentage fill level below which new RX descriptors
+ * will be added to the RX descriptor ring.
+ */
+static unsigned int rx_refill_threshold = 90;
+
+/* This is the percentage fill level to which an RX queue will be refilled
+ * when the "RX refill threshold" is reached.
+ */
+static unsigned int rx_refill_limit = 95;
+
+/*
+ * RX maximum head room required.
+ *
+ * This must be at least 1 to prevent overflow and at least 2 to allow
+ * pipelined receives.
+ */
+#define EFX_RXD_HEAD_ROOM 2
+
+/* Offset of ethernet header within page */
+static inline unsigned int efx_rx_buf_offset(struct efx_nic *efx,
+					     struct efx_rx_buffer *buf)
+{
+	/* Offset is always within one page, so we don't need to consider
+	 * the page order.
+	 */
+	return (((__force unsigned long) buf->dma_addr & (PAGE_SIZE - 1)) +
+		efx->type->rx_buffer_hash_size);
+}
+static inline unsigned int efx_rx_buf_size(struct efx_nic *efx)
+{
+	return PAGE_SIZE << efx->rx_buffer_order;
+}
+
+static u8 *efx_rx_buf_eh(struct efx_nic *efx, struct efx_rx_buffer *buf)
+{
+	if (buf->is_page)
+		return page_address(buf->u.page) + efx_rx_buf_offset(efx, buf);
+	else
+		return ((u8 *)buf->u.skb->data +
+			efx->type->rx_buffer_hash_size);
+}
+
+static inline u32 efx_rx_buf_hash(const u8 *eh)
+{
+	/* The ethernet header is always directly after any hash. */
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) || NET_IP_ALIGN % 4 == 0
+	return __le32_to_cpup((const __le32 *)(eh - 4));
+#else
+	const u8 *data = eh - 4;
+	return ((u32)data[0]       |
+		(u32)data[1] << 8  |
+		(u32)data[2] << 16 |
+		(u32)data[3] << 24);
+#endif
+}
+
+/**
+ * efx_init_rx_buffers_skb - create EFX_RX_BATCH skb-based RX buffers
+ *
+ * @rx_queue:		Efx RX queue
+ *
+ * This allocates EFX_RX_BATCH skbs, maps them for DMA, and populates a
+ * struct efx_rx_buffer for each one. Return a negative error code or 0
+ * on success. May fail having only inserted fewer than EFX_RX_BATCH
+ * buffers.
+ */
+static int efx_init_rx_buffers_skb(struct efx_rx_queue *rx_queue)
+{
+	struct efx_nic *efx = rx_queue->efx;
+	struct net_device *net_dev = efx->net_dev;
+	struct efx_rx_buffer *rx_buf;
+	struct sk_buff *skb;
+	int skb_len = efx->rx_buffer_len;
+	unsigned index, count;
+
+	for (count = 0; count < EFX_RX_BATCH; ++count) {
+		index = rx_queue->added_count & rx_queue->ptr_mask;
+		rx_buf = efx_rx_buffer(rx_queue, index);
+
+		rx_buf->u.skb = skb = netdev_alloc_skb(net_dev, skb_len);
+		if (unlikely(!skb))
+			return -ENOMEM;
+
+		/* Adjust the SKB for padding and checksum */
+		skb_reserve(skb, NET_IP_ALIGN);
+		rx_buf->len = skb_len - NET_IP_ALIGN;
+		rx_buf->is_page = false;
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+		rx_buf->dma_addr = pci_map_single(efx->pci_dev,
+						  skb->data, rx_buf->len,
+						  PCI_DMA_FROMDEVICE);
+		if (unlikely(pci_dma_mapping_error(efx->pci_dev,
+						   rx_buf->dma_addr))) {
+			dev_kfree_skb_any(skb);
+			rx_buf->u.skb = NULL;
+			return -EIO;
+		}
+
+		++rx_queue->added_count;
+		++rx_queue->alloc_skb_count;
+	}
+
+	return 0;
+}
+
+/**
+ * efx_init_rx_buffers_page - create EFX_RX_BATCH page-based RX buffers
+ *
+ * @rx_queue:		Efx RX queue
+ *
+ * This allocates memory for EFX_RX_BATCH receive buffers, maps them for DMA,
+ * and populates struct efx_rx_buffers for each one. Return a negative error
+ * code or 0 on success. If a single page can be split between two buffers,
+ * then the page will either be inserted fully, or not at at all.
+ */
+static int efx_init_rx_buffers_page(struct efx_rx_queue *rx_queue)
+{
+	struct efx_nic *efx = rx_queue->efx;
+	struct efx_rx_buffer *rx_buf;
+	struct page *page;
+	void *page_addr;
+	struct efx_rx_page_state *state;
+	dma_addr_t dma_addr;
+	unsigned index, count;
+
+	/* We can split a page between two buffers */
+	BUILD_BUG_ON(EFX_RX_BATCH & 1);
+
+	for (count = 0; count < EFX_RX_BATCH; ++count) {
+		page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
+				   efx->rx_buffer_order);
+		if (unlikely(page == NULL))
+			return -ENOMEM;
+		dma_addr = pci_map_page(efx->pci_dev, page, 0,
+					efx_rx_buf_size(efx),
+					PCI_DMA_FROMDEVICE);
+		if (unlikely(pci_dma_mapping_error(efx->pci_dev, dma_addr))) {
+			__free_pages(page, efx->rx_buffer_order);
+			return -EIO;
+		}
+		page_addr = page_address(page);
+		state = page_addr;
+		state->refcnt = 0;
+		state->dma_addr = dma_addr;
+
+		page_addr += sizeof(struct efx_rx_page_state);
+		dma_addr += sizeof(struct efx_rx_page_state);
+
+	split:
+		index = rx_queue->added_count & rx_queue->ptr_mask;
+		rx_buf = efx_rx_buffer(rx_queue, index);
+		rx_buf->dma_addr = dma_addr + EFX_PAGE_IP_ALIGN;
+		rx_buf->u.page = page;
+		rx_buf->len = efx->rx_buffer_len - EFX_PAGE_IP_ALIGN;
+		rx_buf->is_page = true;
+		++rx_queue->added_count;
+		++rx_queue->alloc_page_count;
+		++state->refcnt;
+
+		if ((~count & 1) && (efx->rx_buffer_len <= EFX_RX_HALF_PAGE)) {
+			/* Use the second half of the page */
+			get_page(page);
+			dma_addr += (PAGE_SIZE >> 1);
+			page_addr += (PAGE_SIZE >> 1);
+			++count;
+			goto split;
+		}
+	}
+
+	return 0;
+}
+
+static void efx_unmap_rx_buffer(struct efx_nic *efx,
+				struct efx_rx_buffer *rx_buf)
+{
+	if (rx_buf->is_page && rx_buf->u.page) {
+		struct efx_rx_page_state *state;
+
+		state = page_address(rx_buf->u.page);
+		if (--state->refcnt == 0) {
+			pci_unmap_page(efx->pci_dev,
+				       state->dma_addr,
+				       efx_rx_buf_size(efx),
+				       PCI_DMA_FROMDEVICE);
+		}
+	} else if (!rx_buf->is_page && rx_buf->u.skb) {
+		pci_unmap_single(efx->pci_dev, rx_buf->dma_addr,
+				 rx_buf->len, PCI_DMA_FROMDEVICE);
+	}
+}
+
+static void efx_free_rx_buffer(struct efx_nic *efx,
+			       struct efx_rx_buffer *rx_buf)
+{
+	if (rx_buf->is_page && rx_buf->u.page) {
+		__free_pages(rx_buf->u.page, efx->rx_buffer_order);
+		rx_buf->u.page = NULL;
+	} else if (!rx_buf->is_page && rx_buf->u.skb) {
+		dev_kfree_skb_any(rx_buf->u.skb);
+		rx_buf->u.skb = NULL;
+	}
+}
+
+static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
+			       struct efx_rx_buffer *rx_buf)
+{
+	efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
+	efx_free_rx_buffer(rx_queue->efx, rx_buf);
+}
+
+/* Attempt to resurrect the other receive buffer that used to share this page,
+ * which had previously been passed up to the kernel and freed. */
+static void efx_resurrect_rx_buffer(struct efx_rx_queue *rx_queue,
+				    struct efx_rx_buffer *rx_buf)
+{
+	struct efx_rx_page_state *state = page_address(rx_buf->u.page);
+	struct efx_rx_buffer *new_buf;
+	unsigned fill_level, index;
+
+	/* +1 because efx_rx_packet() incremented removed_count. +1 because
+	 * we'd like to insert an additional descriptor whilst leaving
+	 * EFX_RXD_HEAD_ROOM for the non-recycle path */
+	fill_level = (rx_queue->added_count - rx_queue->removed_count + 2);
+	if (unlikely(fill_level > rx_queue->max_fill)) {
+		/* We could place "state" on a list, and drain the list in
+		 * efx_fast_push_rx_descriptors(). For now, this will do. */
+		return;
+	}
+
+	++state->refcnt;
+	get_page(rx_buf->u.page);
+
+	index = rx_queue->added_count & rx_queue->ptr_mask;
+	new_buf = efx_rx_buffer(rx_queue, index);
+	new_buf->dma_addr = rx_buf->dma_addr ^ (PAGE_SIZE >> 1);
+	new_buf->u.page = rx_buf->u.page;
+	new_buf->len = rx_buf->len;
+	new_buf->is_page = true;
+	++rx_queue->added_count;
+}
+
+/* Recycle the given rx buffer directly back into the rx_queue. There is
+ * always room to add this buffer, because we've just popped a buffer. */
+static void efx_recycle_rx_buffer(struct efx_channel *channel,
+				  struct efx_rx_buffer *rx_buf)
+{
+	struct efx_nic *efx = channel->efx;
+	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
+	struct efx_rx_buffer *new_buf;
+	unsigned index;
+
+	if (rx_buf->is_page && efx->rx_buffer_len <= EFX_RX_HALF_PAGE &&
+	    page_count(rx_buf->u.page) == 1)
+		efx_resurrect_rx_buffer(rx_queue, rx_buf);
+
+	index = rx_queue->added_count & rx_queue->ptr_mask;
+	new_buf = efx_rx_buffer(rx_queue, index);
+
+	memcpy(new_buf, rx_buf, sizeof(*new_buf));
+	rx_buf->u.page = NULL;
+	++rx_queue->added_count;
+}
+
+/**
+ * efx_fast_push_rx_descriptors - push new RX descriptors quickly
+ * @rx_queue:		RX descriptor queue
+ * This will aim to fill the RX descriptor queue up to
+ * @rx_queue->@fast_fill_limit. If there is insufficient atomic
+ * memory to do so, a slow fill will be scheduled.
+ *
+ * The caller must provide serialisation (none is used here). In practise,
+ * this means this function must run from the NAPI handler, or be called
+ * when NAPI is disabled.
+ */
+void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
+{
+	struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
+	unsigned fill_level;
+	int space, rc = 0;
+
+	/* Calculate current fill level, and exit if we don't need to fill */
+	fill_level = (rx_queue->added_count - rx_queue->removed_count);
+	EFX_BUG_ON_PARANOID(fill_level > rx_queue->efx->rxq_entries);
+	if (fill_level >= rx_queue->fast_fill_trigger)
+		goto out;
+
+	/* Record minimum fill level */
+	if (unlikely(fill_level < rx_queue->min_fill)) {
+		if (fill_level)
+			rx_queue->min_fill = fill_level;
+	}
+
+	space = rx_queue->fast_fill_limit - fill_level;
+	if (space < EFX_RX_BATCH)
+		goto out;
+
+	netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
+		   "RX queue %d fast-filling descriptor ring from"
+		   " level %d to level %d using %s allocation\n",
+		   efx_rx_queue_index(rx_queue), fill_level,
+		   rx_queue->fast_fill_limit,
+		   channel->rx_alloc_push_pages ? "page" : "skb");
+
+	do {
+		if (channel->rx_alloc_push_pages)
+			rc = efx_init_rx_buffers_page(rx_queue);
+		else
+			rc = efx_init_rx_buffers_skb(rx_queue);
+		if (unlikely(rc)) {
+			/* Ensure that we don't leave the rx queue empty */
+			if (rx_queue->added_count == rx_queue->removed_count)
+				efx_schedule_slow_fill(rx_queue);
+			goto out;
+		}
+	} while ((space -= EFX_RX_BATCH) >= EFX_RX_BATCH);
+
+	netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
+		   "RX queue %d fast-filled descriptor ring "
+		   "to level %d\n", efx_rx_queue_index(rx_queue),
+		   rx_queue->added_count - rx_queue->removed_count);
+
+ out:
+	if (rx_queue->notified_count != rx_queue->added_count)
+		efx_nic_notify_rx_desc(rx_queue);
+}
+
+void efx_rx_slow_fill(unsigned long context)
+{
+	struct efx_rx_queue *rx_queue = (struct efx_rx_queue *)context;
+	struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
+
+	/* Post an event to cause NAPI to run and refill the queue */
+	efx_nic_generate_fill_event(channel);
+	++rx_queue->slow_fill_count;
+}
+
+static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
+				     struct efx_rx_buffer *rx_buf,
+				     int len, bool *discard,
+				     bool *leak_packet)
+{
+	struct efx_nic *efx = rx_queue->efx;
+	unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
+
+	if (likely(len <= max_len))
+		return;
+
+	/* The packet must be discarded, but this is only a fatal error
+	 * if the caller indicated it was
+	 */
+	*discard = true;
+
+	if ((len > rx_buf->len) && EFX_WORKAROUND_8071(efx)) {
+		if (net_ratelimit())
+			netif_err(efx, rx_err, efx->net_dev,
+				  " RX queue %d seriously overlength "
+				  "RX event (0x%x > 0x%x+0x%x). Leaking\n",
+				  efx_rx_queue_index(rx_queue), len, max_len,
+				  efx->type->rx_buffer_padding);
+		/* If this buffer was skb-allocated, then the meta
+		 * data at the end of the skb will be trashed. So
+		 * we have no choice but to leak the fragment.
+		 */
+		*leak_packet = !rx_buf->is_page;
+		efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY);
+	} else {
+		if (net_ratelimit())
+			netif_err(efx, rx_err, efx->net_dev,
+				  " RX queue %d overlength RX event "
+				  "(0x%x > 0x%x)\n",
+				  efx_rx_queue_index(rx_queue), len, max_len);
+	}
+
+	efx_rx_queue_channel(rx_queue)->n_rx_overlength++;
+}
+
+/* Pass a received packet up through the generic GRO stack
+ *
+ * Handles driverlink veto, and passes the fragment up via
+ * the appropriate GRO method
+ */
+static void efx_rx_packet_gro(struct efx_channel *channel,
+			      struct efx_rx_buffer *rx_buf,
+			      const u8 *eh, bool checksummed)
+{
+	struct napi_struct *napi = &channel->napi_str;
+	gro_result_t gro_result;
+
+	/* Pass the skb/page into the GRO engine */
+	if (rx_buf->is_page) {
+		struct efx_nic *efx = channel->efx;
+		struct page *page = rx_buf->u.page;
+		struct sk_buff *skb;
+
+		rx_buf->u.page = NULL;
+
+		skb = napi_get_frags(napi);
+		if (!skb) {
+			put_page(page);
+			return;
+		}
+
+		if (efx->net_dev->features & NETIF_F_RXHASH)
+			skb->rxhash = efx_rx_buf_hash(eh);
+
+		skb_shinfo(skb)->frags[0].page = page;
+		skb_shinfo(skb)->frags[0].page_offset =
+			efx_rx_buf_offset(efx, rx_buf);
+		skb_shinfo(skb)->frags[0].size = rx_buf->len;
+		skb_shinfo(skb)->nr_frags = 1;
+
+		skb->len = rx_buf->len;
+		skb->data_len = rx_buf->len;
+		skb->truesize += rx_buf->len;
+		skb->ip_summed =
+			checksummed ? CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
+
+		skb_record_rx_queue(skb, channel->channel);
+
+		gro_result = napi_gro_frags(napi);
+	} else {
+		struct sk_buff *skb = rx_buf->u.skb;
+
+		EFX_BUG_ON_PARANOID(!checksummed);
+		rx_buf->u.skb = NULL;
+
+		gro_result = napi_gro_receive(napi, skb);
+	}
+
+	if (gro_result == GRO_NORMAL) {
+		channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
+	} else if (gro_result != GRO_DROP) {
+		channel->rx_alloc_level += RX_ALLOC_FACTOR_GRO;
+		channel->irq_mod_score += 2;
+	}
+}
+
+void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
+		   unsigned int len, bool checksummed, bool discard)
+{
+	struct efx_nic *efx = rx_queue->efx;
+	struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
+	struct efx_rx_buffer *rx_buf;
+	bool leak_packet = false;
+
+	rx_buf = efx_rx_buffer(rx_queue, index);
+
+	/* This allows the refill path to post another buffer.
+	 * EFX_RXD_HEAD_ROOM ensures that the slot we are using
+	 * isn't overwritten yet.
+	 */
+	rx_queue->removed_count++;
+
+	/* Validate the length encoded in the event vs the descriptor pushed */
+	efx_rx_packet__check_len(rx_queue, rx_buf, len,
+				 &discard, &leak_packet);
+
+	netif_vdbg(efx, rx_status, efx->net_dev,
+		   "RX queue %d received id %x at %llx+%x %s%s\n",
+		   efx_rx_queue_index(rx_queue), index,
+		   (unsigned long long)rx_buf->dma_addr, len,
+		   (checksummed ? " [SUMMED]" : ""),
+		   (discard ? " [DISCARD]" : ""));
+
+	/* Discard packet, if instructed to do so */
+	if (unlikely(discard)) {
+		if (unlikely(leak_packet))
+			channel->n_skbuff_leaks++;
+		else
+			efx_recycle_rx_buffer(channel, rx_buf);
+
+		/* Don't hold off the previous receive */
+		rx_buf = NULL;
+		goto out;
+	}
+
+	/* Release card resources - assumes all RX buffers consumed in-order
+	 * per RX queue
+	 */
+	efx_unmap_rx_buffer(efx, rx_buf);
+
+	/* Prefetch nice and early so data will (hopefully) be in cache by
+	 * the time we look at it.
+	 */
+	prefetch(efx_rx_buf_eh(efx, rx_buf));
+
+	/* Pipeline receives so that we give time for packet headers to be
+	 * prefetched into cache.
+	 */
+	rx_buf->len = len - efx->type->rx_buffer_hash_size;
+out:
+	if (channel->rx_pkt)
+		__efx_rx_packet(channel,
+				channel->rx_pkt, channel->rx_pkt_csummed);
+	channel->rx_pkt = rx_buf;
+	channel->rx_pkt_csummed = checksummed;
+}
+
+/* Handle a received packet.  Second half: Touches packet payload. */
+void __efx_rx_packet(struct efx_channel *channel,
+		     struct efx_rx_buffer *rx_buf, bool checksummed)
+{
+	struct efx_nic *efx = channel->efx;
+	struct sk_buff *skb;
+	u8 *eh = efx_rx_buf_eh(efx, rx_buf);
+
+	/* If we're in loopback test, then pass the packet directly to the
+	 * loopback layer, and free the rx_buf here
+	 */
+	if (unlikely(efx->loopback_selftest)) {
+		efx_loopback_rx_packet(efx, eh, rx_buf->len);
+		efx_free_rx_buffer(efx, rx_buf);
+		return;
+	}
+
+	if (!rx_buf->is_page) {
+		skb = rx_buf->u.skb;
+
+		prefetch(skb_shinfo(skb));
+
+		skb_reserve(skb, efx->type->rx_buffer_hash_size);
+		skb_put(skb, rx_buf->len);
+
+		if (efx->net_dev->features & NETIF_F_RXHASH)
+			skb->rxhash = efx_rx_buf_hash(eh);
+
+		/* Move past the ethernet header. rx_buf->data still points
+		 * at the ethernet header */
+		skb->protocol = eth_type_trans(skb, efx->net_dev);
+
+		skb_record_rx_queue(skb, channel->channel);
+	}
+
+	if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
+		checksummed = false;
+
+	if (likely(checksummed || rx_buf->is_page)) {
+		efx_rx_packet_gro(channel, rx_buf, eh, checksummed);
+		return;
+	}
+
+	/* We now own the SKB */
+	skb = rx_buf->u.skb;
+	rx_buf->u.skb = NULL;
+
+	/* Set the SKB flags */
+	skb_checksum_none_assert(skb);
+
+	/* Pass the packet up */
+	netif_receive_skb(skb);
+
+	/* Update allocation strategy method */
+	channel->rx_alloc_level += RX_ALLOC_FACTOR_SKB;
+}
+
+void efx_rx_strategy(struct efx_channel *channel)
+{
+	enum efx_rx_alloc_method method = rx_alloc_method;
+
+	/* Only makes sense to use page based allocation if GRO is enabled */
+	if (!(channel->efx->net_dev->features & NETIF_F_GRO)) {
+		method = RX_ALLOC_METHOD_SKB;
+	} else if (method == RX_ALLOC_METHOD_AUTO) {
+		/* Constrain the rx_alloc_level */
+		if (channel->rx_alloc_level < 0)
+			channel->rx_alloc_level = 0;
+		else if (channel->rx_alloc_level > RX_ALLOC_LEVEL_MAX)
+			channel->rx_alloc_level = RX_ALLOC_LEVEL_MAX;
+
+		/* Decide on the allocation method */
+		method = ((channel->rx_alloc_level > RX_ALLOC_LEVEL_GRO) ?
+			  RX_ALLOC_METHOD_PAGE : RX_ALLOC_METHOD_SKB);
+	}
+
+	/* Push the option */
+	channel->rx_alloc_push_pages = (method == RX_ALLOC_METHOD_PAGE);
+}
+
+int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
+{
+	struct efx_nic *efx = rx_queue->efx;
+	unsigned int entries;
+	int rc;
+
+	/* Create the smallest power-of-two aligned ring */
+	entries = max(roundup_pow_of_two(efx->rxq_entries), EFX_MIN_DMAQ_SIZE);
+	EFX_BUG_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE);
+	rx_queue->ptr_mask = entries - 1;
+
+	netif_dbg(efx, probe, efx->net_dev,
+		  "creating RX queue %d size %#x mask %#x\n",
+		  efx_rx_queue_index(rx_queue), efx->rxq_entries,
+		  rx_queue->ptr_mask);
+
+	/* Allocate RX buffers */
+	rx_queue->buffer = kzalloc(entries * sizeof(*rx_queue->buffer),
+				   GFP_KERNEL);
+	if (!rx_queue->buffer)
+		return -ENOMEM;
+
+	rc = efx_nic_probe_rx(rx_queue);
+	if (rc) {
+		kfree(rx_queue->buffer);
+		rx_queue->buffer = NULL;
+	}
+	return rc;
+}
+
+void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
+{
+	struct efx_nic *efx = rx_queue->efx;
+	unsigned int max_fill, trigger, limit;
+
+	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
+		  "initialising RX queue %d\n", efx_rx_queue_index(rx_queue));
+
+	/* Initialise ptr fields */
+	rx_queue->added_count = 0;
+	rx_queue->notified_count = 0;
+	rx_queue->removed_count = 0;
+	rx_queue->min_fill = -1U;
+
+	/* Initialise limit fields */
+	max_fill = efx->rxq_entries - EFX_RXD_HEAD_ROOM;
+	trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
+	limit = max_fill * min(rx_refill_limit, 100U) / 100U;
+
+	rx_queue->max_fill = max_fill;
+	rx_queue->fast_fill_trigger = trigger;
+	rx_queue->fast_fill_limit = limit;
+
+	/* Set up RX descriptor ring */
+	efx_nic_init_rx(rx_queue);
+}
+
+void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
+{
+	int i;
+	struct efx_rx_buffer *rx_buf;
+
+	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
+		  "shutting down RX queue %d\n", efx_rx_queue_index(rx_queue));
+
+	del_timer_sync(&rx_queue->slow_fill);
+	efx_nic_fini_rx(rx_queue);
+
+	/* Release RX buffers NB start at index 0 not current HW ptr */
+	if (rx_queue->buffer) {
+		for (i = 0; i <= rx_queue->ptr_mask; i++) {
+			rx_buf = efx_rx_buffer(rx_queue, i);
+			efx_fini_rx_buffer(rx_queue, rx_buf);
+		}
+	}
+}
+
+void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
+{
+	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
+		  "destroying RX queue %d\n", efx_rx_queue_index(rx_queue));
+
+	efx_nic_remove_rx(rx_queue);
+
+	kfree(rx_queue->buffer);
+	rx_queue->buffer = NULL;
+}
+
+
+module_param(rx_alloc_method, int, 0644);
+MODULE_PARM_DESC(rx_alloc_method, "Allocation method used for RX buffers");
+
+module_param(rx_refill_threshold, uint, 0444);
+MODULE_PARM_DESC(rx_refill_threshold,
+		 "RX descriptor ring fast/slow fill threshold (%)");
+