drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c

/*******************************************************************************

  Intel 10 Gigabit PCI Express Linux driver
  Copyright(c) 1999 - 2012 Intel Corporation.

  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.

  This program is distributed in the hope it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  more details.

  You should have received a copy of the GNU General Public License along with
  this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

  The full GNU General Public License is included in this distribution in
  the file called "COPYING".

  Contact Information:
  e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
  Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497

*******************************************************************************/

#include "ixgbe.h"
#include "ixgbe_sriov.h"

/**
 * ixgbe_cache_ring_rss - Descriptor ring to register mapping for RSS
 * @adapter: board private structure to initialize
 *
 * Cache the descriptor ring offsets for RSS to the assigned rings.
 *
 **/
static inline bool ixgbe_cache_ring_rss(struct ixgbe_adapter *adapter)
{
	int i;

	if (!(adapter->flags & IXGBE_FLAG_RSS_ENABLED))
		return false;

	for (i = 0; i < adapter->num_rx_queues; i++)
		adapter->rx_ring[i]->reg_idx = i;
	for (i = 0; i < adapter->num_tx_queues; i++)
		adapter->tx_ring[i]->reg_idx = i;

	return true;
}
#ifdef CONFIG_IXGBE_DCB

/* ixgbe_get_first_reg_idx - Return first register index associated with ring */
static void ixgbe_get_first_reg_idx(struct ixgbe_adapter *adapter, u8 tc,
				    unsigned int *tx, unsigned int *rx)
{
	struct net_device *dev = adapter->netdev;
	struct ixgbe_hw *hw = &adapter->hw;
	u8 num_tcs = netdev_get_num_tc(dev);

	*tx = 0;
	*rx = 0;

	switch (hw->mac.type) {
	case ixgbe_mac_82598EB:
		*tx = tc << 2;
		*rx = tc << 3;
		break;
	case ixgbe_mac_82599EB:
	case ixgbe_mac_X540:
		if (num_tcs > 4) {
			if (tc < 3) {
				*tx = tc << 5;
				*rx = tc << 4;
			} else if (tc <  5) {
				*tx = ((tc + 2) << 4);
				*rx = tc << 4;
			} else if (tc < num_tcs) {
				*tx = ((tc + 8) << 3);
				*rx = tc << 4;
			}
		} else {
			*rx =  tc << 5;
			switch (tc) {
			case 0:
				*tx =  0;
				break;
			case 1:
				*tx = 64;
				break;
			case 2:
				*tx = 96;
				break;
			case 3:
				*tx = 112;
				break;
			default:
				break;
			}
		}
		break;
	default:
		break;
	}
}

/**
 * ixgbe_cache_ring_dcb - Descriptor ring to register mapping for DCB
 * @adapter: board private structure to initialize
 *
 * Cache the descriptor ring offsets for DCB to the assigned rings.
 *
 **/
static inline bool ixgbe_cache_ring_dcb(struct ixgbe_adapter *adapter)
{
	struct net_device *dev = adapter->netdev;
	int i, j, k;
	u8 num_tcs = netdev_get_num_tc(dev);

	if (!num_tcs)
		return false;

	for (i = 0, k = 0; i < num_tcs; i++) {
		unsigned int tx_s, rx_s;
		u16 count = dev->tc_to_txq[i].count;

		ixgbe_get_first_reg_idx(adapter, i, &tx_s, &rx_s);
		for (j = 0; j < count; j++, k++) {
			adapter->tx_ring[k]->reg_idx = tx_s + j;
			adapter->rx_ring[k]->reg_idx = rx_s + j;
			adapter->tx_ring[k]->dcb_tc = i;
			adapter->rx_ring[k]->dcb_tc = i;
		}
	}

	return true;
}
#endif

#ifdef IXGBE_FCOE
/**
 * ixgbe_cache_ring_fcoe - Descriptor ring to register mapping for the FCoE
 * @adapter: board private structure to initialize
 *
 * Cache the descriptor ring offsets for FCoE mode to the assigned rings.
 *
 */
static inline bool ixgbe_cache_ring_fcoe(struct ixgbe_adapter *adapter)
{
	struct ixgbe_ring_feature *f = &adapter->ring_feature[RING_F_FCOE];
	int i;
	u8 fcoe_rx_i = 0, fcoe_tx_i = 0;

	if (!(adapter->flags & IXGBE_FLAG_FCOE_ENABLED))
		return false;

	if (adapter->flags & IXGBE_FLAG_RSS_ENABLED) {
		ixgbe_cache_ring_rss(adapter);

		fcoe_rx_i = f->offset;
		fcoe_tx_i = f->offset;
	}
	for (i = 0; i < f->indices; i++, fcoe_rx_i++, fcoe_tx_i++) {
		adapter->rx_ring[f->offset + i]->reg_idx = fcoe_rx_i;
		adapter->tx_ring[f->offset + i]->reg_idx = fcoe_tx_i;
	}
	return true;
}

#endif /* IXGBE_FCOE */
/**
 * ixgbe_cache_ring_sriov - Descriptor ring to register mapping for sriov
 * @adapter: board private structure to initialize
 *
 * SR-IOV doesn't use any descriptor rings but changes the default if
 * no other mapping is used.
 *
 */
static inline bool ixgbe_cache_ring_sriov(struct ixgbe_adapter *adapter)
{
	adapter->rx_ring[0]->reg_idx = adapter->num_vfs * 2;
	adapter->tx_ring[0]->reg_idx = adapter->num_vfs * 2;
	if (adapter->num_vfs)
		return true;
	else
		return false;
}

/**
 * ixgbe_cache_ring_register - Descriptor ring to register mapping
 * @adapter: board private structure to initialize
 *
 * Once we know the feature-set enabled for the device, we'll cache
 * the register offset the descriptor ring is assigned to.
 *
 * Note, the order the various feature calls is important.  It must start with
 * the "most" features enabled at the same time, then trickle down to the
 * least amount of features turned on at once.
 **/
static void ixgbe_cache_ring_register(struct ixgbe_adapter *adapter)
{
	/* start with default case */
	adapter->rx_ring[0]->reg_idx = 0;
	adapter->tx_ring[0]->reg_idx = 0;

	if (ixgbe_cache_ring_sriov(adapter))
		return;

#ifdef CONFIG_IXGBE_DCB
	if (ixgbe_cache_ring_dcb(adapter))
		return;
#endif

#ifdef IXGBE_FCOE
	if (ixgbe_cache_ring_fcoe(adapter))
		return;
#endif /* IXGBE_FCOE */

	if (ixgbe_cache_ring_rss(adapter))
		return;
}

/**
 * ixgbe_set_sriov_queues - Allocate queues for IOV use
 * @adapter: board private structure to initialize
 *
 * IOV doesn't actually use anything, so just NAK the
 * request for now and let the other queue routines
 * figure out what to do.
 */
static inline bool ixgbe_set_sriov_queues(struct ixgbe_adapter *adapter)
{
	return false;
}

/**
 * ixgbe_set_rss_queues - Allocate queues for RSS
 * @adapter: board private structure to initialize
 *
 * This is our "base" multiqueue mode.  RSS (Receive Side Scaling) will try
 * to allocate one Rx queue per CPU, and if available, one Tx queue per CPU.
 *
 **/
static bool ixgbe_set_rss_queues(struct ixgbe_adapter *adapter)
{
	struct ixgbe_ring_feature *f;
	u16 rss_i;

	if (!(adapter->flags & IXGBE_FLAG_RSS_ENABLED)) {
		adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;
		return false;
	}

	/* set mask for 16 queue limit of RSS */
	f = &adapter->ring_feature[RING_F_RSS];
	rss_i = f->limit;

	f->indices = rss_i;
	f->mask = 0xF;

	/*
	 * Use Flow Director in addition to RSS to ensure the best
	 * distribution of flows across cores, even when an FDIR flow
	 * isn't matched.
	 */
	if (adapter->flags & IXGBE_FLAG_FDIR_HASH_CAPABLE) {
		f = &adapter->ring_feature[RING_F_FDIR];

		f->indices = min_t(u16, num_online_cpus(), f->limit);
		rss_i = max_t(u16, rss_i, f->indices);
	}

	adapter->num_rx_queues = rss_i;
	adapter->num_tx_queues = rss_i;

	return true;
}

#ifdef IXGBE_FCOE
/**
 * ixgbe_set_fcoe_queues - Allocate queues for Fiber Channel over Ethernet (FCoE)
 * @adapter: board private structure to initialize
 *
 * FCoE RX FCRETA can use up to 8 rx queues for up to 8 different exchanges.
 * Offset is used as the index of the first rx queue used by FCoE.
 **/
static inline bool ixgbe_set_fcoe_queues(struct ixgbe_adapter *adapter)
{
	struct ixgbe_ring_feature *f = &adapter->ring_feature[RING_F_FCOE];

	if (!(adapter->flags & IXGBE_FLAG_FCOE_ENABLED))
		return false;

	f->indices = min_t(int, num_online_cpus(), f->limit);

	adapter->num_rx_queues = 1;
	adapter->num_tx_queues = 1;

	if (adapter->flags & IXGBE_FLAG_RSS_ENABLED) {
		e_info(probe, "FCoE enabled with RSS\n");
		ixgbe_set_rss_queues(adapter);
	}

	/* adding FCoE rx rings to the end */
	f->offset = adapter->num_rx_queues;
	adapter->num_rx_queues += f->indices;
	adapter->num_tx_queues += f->indices;

	return true;
}
#endif /* IXGBE_FCOE */

/* Artificial max queue cap per traffic class in DCB mode */
#define DCB_QUEUE_CAP 8

#ifdef CONFIG_IXGBE_DCB
static inline bool ixgbe_set_dcb_queues(struct ixgbe_adapter *adapter)
{
	int per_tc_q, q, i, offset = 0;
	struct net_device *dev = adapter->netdev;
	int tcs = netdev_get_num_tc(dev);

	if (!tcs)
		return false;

	/* Map queue offset and counts onto allocated tx queues */
	per_tc_q = min_t(unsigned int, dev->num_tx_queues / tcs, DCB_QUEUE_CAP);
	q = min_t(int, num_online_cpus(), per_tc_q);

	for (i = 0; i < tcs; i++) {
		netdev_set_tc_queue(dev, i, q, offset);
		offset += q;
	}

	adapter->num_tx_queues = q * tcs;
	adapter->num_rx_queues = q * tcs;

#ifdef IXGBE_FCOE
	/* FCoE enabled queues require special configuration indexed
	 * by feature specific indices and offset. Here we map FCoE
	 * indices onto the DCB queue pairs allowing FCoE to own
	 * configuration later.
	 */
	if (adapter->flags & IXGBE_FLAG_FCOE_ENABLED) {
		u8 prio_tc[MAX_USER_PRIORITY] = {0};
		int tc;
		struct ixgbe_ring_feature *f =
					&adapter->ring_feature[RING_F_FCOE];

		ixgbe_dcb_unpack_map(&adapter->dcb_cfg, DCB_TX_CONFIG, prio_tc);
		tc = prio_tc[adapter->fcoe.up];
		f->indices = dev->tc_to_txq[tc].count;
		f->offset = dev->tc_to_txq[tc].offset;
	}
#endif

	return true;
}
#endif

/**
 * ixgbe_set_num_queues - Allocate queues for device, feature dependent
 * @adapter: board private structure to initialize
 *
 * This is the top level queue allocation routine.  The order here is very
 * important, starting with the "most" number of features turned on at once,
 * and ending with the smallest set of features.  This way large combinations
 * can be allocated if they're turned on, and smaller combinations are the
 * fallthrough conditions.
 *
 **/
static int ixgbe_set_num_queues(struct ixgbe_adapter *adapter)
{
	/* Start with base case */
	adapter->num_rx_queues = 1;
	adapter->num_tx_queues = 1;
	adapter->num_rx_pools = adapter->num_rx_queues;
	adapter->num_rx_queues_per_pool = 1;

	if (ixgbe_set_sriov_queues(adapter))
		goto done;

#ifdef CONFIG_IXGBE_DCB
	if (ixgbe_set_dcb_queues(adapter))
		goto done;

#endif
#ifdef IXGBE_FCOE
	if (ixgbe_set_fcoe_queues(adapter))
		goto done;

#endif /* IXGBE_FCOE */
	if (ixgbe_set_rss_queues(adapter))
		goto done;

	/* fallback to base case */
	adapter->num_rx_queues = 1;
	adapter->num_tx_queues = 1;

done:
	if ((adapter->netdev->reg_state == NETREG_UNREGISTERED) ||
	    (adapter->netdev->reg_state == NETREG_UNREGISTERING))
		return 0;

	/* Notify the stack of the (possibly) reduced queue counts. */
	netif_set_real_num_tx_queues(adapter->netdev, adapter->num_tx_queues);
	return netif_set_real_num_rx_queues(adapter->netdev,
					    adapter->num_rx_queues);
}

static void ixgbe_acquire_msix_vectors(struct ixgbe_adapter *adapter,
				       int vectors)
{
	int err, vector_threshold;

	/* We'll want at least 2 (vector_threshold):
	 * 1) TxQ[0] + RxQ[0] handler
	 * 2) Other (Link Status Change, etc.)
	 */
	vector_threshold = MIN_MSIX_COUNT;

	/*
	 * The more we get, the more we will assign to Tx/Rx Cleanup
	 * for the separate queues...where Rx Cleanup >= Tx Cleanup.
	 * Right now, we simply care about how many we'll get; we'll
	 * set them up later while requesting irq's.
	 */
	while (vectors >= vector_threshold) {
		err = pci_enable_msix(adapter->pdev, adapter->msix_entries,
				      vectors);
		if (!err) /* Success in acquiring all requested vectors. */
			break;
		else if (err < 0)
			vectors = 0; /* Nasty failure, quit now */
		else /* err == number of vectors we should try again with */
			vectors = err;
	}

	if (vectors < vector_threshold) {
		/* Can't allocate enough MSI-X interrupts?  Oh well.
		 * This just means we'll go with either a single MSI
		 * vector or fall back to legacy interrupts.
		 */
		netif_printk(adapter, hw, KERN_DEBUG, adapter->netdev,
			     "Unable to allocate MSI-X interrupts\n");
		adapter->flags &= ~IXGBE_FLAG_MSIX_ENABLED;
		kfree(adapter->msix_entries);
		adapter->msix_entries = NULL;
	} else {
		adapter->flags |= IXGBE_FLAG_MSIX_ENABLED; /* Woot! */
		/*
		 * Adjust for only the vectors we'll use, which is minimum
		 * of max_msix_q_vectors + NON_Q_VECTORS, or the number of
		 * vectors we were allocated.
		 */
		vectors -= NON_Q_VECTORS;
		adapter->num_q_vectors = min(vectors, adapter->max_q_vectors);
	}
}

static void ixgbe_add_ring(struct ixgbe_ring *ring,
			   struct ixgbe_ring_container *head)
{
	ring->next = head->ring;
	head->ring = ring;
	head->count++;
}

/**
 * ixgbe_alloc_q_vector - Allocate memory for a single interrupt vector
 * @adapter: board private structure to initialize
 * @v_count: q_vectors allocated on adapter, used for ring interleaving
 * @v_idx: index of vector in adapter struct
 * @txr_count: total number of Tx rings to allocate
 * @txr_idx: index of first Tx ring to allocate
 * @rxr_count: total number of Rx rings to allocate
 * @rxr_idx: index of first Rx ring to allocate
 *
 * We allocate one q_vector.  If allocation fails we return -ENOMEM.
 **/
static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
				int v_count, int v_idx,
				int txr_count, int txr_idx,
				int rxr_count, int rxr_idx)
{
	struct ixgbe_q_vector *q_vector;
	struct ixgbe_ring *ring;
	int node = -1;
	int cpu = -1;
	int ring_count, size;

	ring_count = txr_count + rxr_count;
	size = sizeof(struct ixgbe_q_vector) +
	       (sizeof(struct ixgbe_ring) * ring_count);

	/* customize cpu for Flow Director mapping */
	if (adapter->flags & IXGBE_FLAG_FDIR_HASH_CAPABLE) {
		if (cpu_online(v_idx)) {
			cpu = v_idx;
			node = cpu_to_node(cpu);
		}
	}

	/* allocate q_vector and rings */
	q_vector = kzalloc_node(size, GFP_KERNEL, node);
	if (!q_vector)
		q_vector = kzalloc(size, GFP_KERNEL);
	if (!q_vector)
		return -ENOMEM;

	/* setup affinity mask and node */
	if (cpu != -1)
		cpumask_set_cpu(cpu, &q_vector->affinity_mask);
	else
		cpumask_copy(&q_vector->affinity_mask, cpu_online_mask);
	q_vector->numa_node = node;

	/* initialize NAPI */
	netif_napi_add(adapter->netdev, &q_vector->napi,
		       ixgbe_poll, 64);

	/* tie q_vector and adapter together */
	adapter->q_vector[v_idx] = q_vector;
	q_vector->adapter = adapter;
	q_vector->v_idx = v_idx;

	/* initialize work limits */
	q_vector->tx.work_limit = adapter->tx_work_limit;

	/* initialize pointer to rings */
	ring = q_vector->ring;

	while (txr_count) {
		/* assign generic ring traits */
		ring->dev = &adapter->pdev->dev;
		ring->netdev = adapter->netdev;

		/* configure backlink on ring */
		ring->q_vector = q_vector;

		/* update q_vector Tx values */
		ixgbe_add_ring(ring, &q_vector->tx);

		/* apply Tx specific ring traits */
		ring->count = adapter->tx_ring_count;
		ring->queue_index = txr_idx;

		/* assign ring to adapter */
		adapter->tx_ring[txr_idx] = ring;

		/* update count and index */
		txr_count--;
		txr_idx += v_count;

		/* push pointer to next ring */
		ring++;
	}

	while (rxr_count) {
		/* assign generic ring traits */
		ring->dev = &adapter->pdev->dev;
		ring->netdev = adapter->netdev;

		/* configure backlink on ring */
		ring->q_vector = q_vector;

		/* update q_vector Rx values */
		ixgbe_add_ring(ring, &q_vector->rx);

		/*
		 * 82599 errata, UDP frames with a 0 checksum
		 * can be marked as checksum errors.
		 */
		if (adapter->hw.mac.type == ixgbe_mac_82599EB)
			set_bit(__IXGBE_RX_CSUM_UDP_ZERO_ERR, &ring->state);

#ifdef IXGBE_FCOE
		if (adapter->netdev->features & NETIF_F_FCOE_MTU) {
			struct ixgbe_ring_feature *f;
			f = &adapter->ring_feature[RING_F_FCOE];
			if ((rxr_idx >= f->offset) &&
			    (rxr_idx < f->offset + f->indices))
				set_bit(__IXGBE_RX_FCOE, &ring->state);
		}

#endif /* IXGBE_FCOE */
		/* apply Rx specific ring traits */
		ring->count = adapter->rx_ring_count;
		ring->queue_index = rxr_idx;

		/* assign ring to adapter */
		adapter->rx_ring[rxr_idx] = ring;

		/* update count and index */
		rxr_count--;
		rxr_idx += v_count;

		/* push pointer to next ring */
		ring++;
	}

	return 0;
}

/**
 * ixgbe_free_q_vector - Free memory allocated for specific interrupt vector
 * @adapter: board private structure to initialize
 * @v_idx: Index of vector to be freed
 *
 * This function frees the memory allocated to the q_vector.  In addition if
 * NAPI is enabled it will delete any references to the NAPI struct prior
 * to freeing the q_vector.
 **/
static void ixgbe_free_q_vector(struct ixgbe_adapter *adapter, int v_idx)
{
	struct ixgbe_q_vector *q_vector = adapter->q_vector[v_idx];
	struct ixgbe_ring *ring;

	ixgbe_for_each_ring(ring, q_vector->tx)
		adapter->tx_ring[ring->queue_index] = NULL;

	ixgbe_for_each_ring(ring, q_vector->rx)
		adapter->rx_ring[ring->queue_index] = NULL;

	adapter->q_vector[v_idx] = NULL;
	netif_napi_del(&q_vector->napi);

	/*
	 * ixgbe_get_stats64() might access the rings on this vector,
	 * we must wait a grace period before freeing it.
	 */
	kfree_rcu(q_vector, rcu);
}

/**
 * ixgbe_alloc_q_vectors - Allocate memory for interrupt vectors
 * @adapter: board private structure to initialize
 *
 * We allocate one q_vector per queue interrupt.  If allocation fails we
 * return -ENOMEM.
 **/
static int ixgbe_alloc_q_vectors(struct ixgbe_adapter *adapter)
{
	int q_vectors = adapter->num_q_vectors;
	int rxr_remaining = adapter->num_rx_queues;
	int txr_remaining = adapter->num_tx_queues;
	int rxr_idx = 0, txr_idx = 0, v_idx = 0;
	int err;

	/* only one q_vector if MSI-X is disabled. */
	if (!(adapter->flags & IXGBE_FLAG_MSIX_ENABLED))
		q_vectors = 1;

	if (q_vectors >= (rxr_remaining + txr_remaining)) {
		for (; rxr_remaining; v_idx++) {
			err = ixgbe_alloc_q_vector(adapter, q_vectors, v_idx,
						   0, 0, 1, rxr_idx);

			if (err)
				goto err_out;

			/* update counts and index */
			rxr_remaining--;
			rxr_idx++;
		}
	}

	for (; v_idx < q_vectors; v_idx++) {
		int rqpv = DIV_ROUND_UP(rxr_remaining, q_vectors - v_idx);
		int tqpv = DIV_ROUND_UP(txr_remaining, q_vectors - v_idx);
		err = ixgbe_alloc_q_vector(adapter, q_vectors, v_idx,
					   tqpv, txr_idx,
					   rqpv, rxr_idx);

		if (err)
			goto err_out;

		/* update counts and index */
		rxr_remaining -= rqpv;
		txr_remaining -= tqpv;
		rxr_idx++;
		txr_idx++;
	}

	return 0;

err_out:
	adapter->num_tx_queues = 0;
	adapter->num_rx_queues = 0;
	adapter->num_q_vectors = 0;

	while (v_idx--)
		ixgbe_free_q_vector(adapter, v_idx);

	return -ENOMEM;
}

/**
 * ixgbe_free_q_vectors - Free memory allocated for interrupt vectors
 * @adapter: board private structure to initialize
 *
 * This function frees the memory allocated to the q_vectors.  In addition if
 * NAPI is enabled it will delete any references to the NAPI struct prior
 * to freeing the q_vector.
 **/
static void ixgbe_free_q_vectors(struct ixgbe_adapter *adapter)
{
	int v_idx = adapter->num_q_vectors;

	adapter->num_tx_queues = 0;
	adapter->num_rx_queues = 0;
	adapter->num_q_vectors = 0;

	while (v_idx--)
		ixgbe_free_q_vector(adapter, v_idx);
}

static void ixgbe_reset_interrupt_capability(struct ixgbe_adapter *adapter)
{
	if (adapter->flags & IXGBE_FLAG_MSIX_ENABLED) {
		adapter->flags &= ~IXGBE_FLAG_MSIX_ENABLED;
		pci_disable_msix(adapter->pdev);
		kfree(adapter->msix_entries);
		adapter->msix_entries = NULL;
	} else if (adapter->flags & IXGBE_FLAG_MSI_ENABLED) {
		adapter->flags &= ~IXGBE_FLAG_MSI_ENABLED;
		pci_disable_msi(adapter->pdev);
	}
}

/**
 * ixgbe_set_interrupt_capability - set MSI-X or MSI if supported
 * @adapter: board private structure to initialize
 *
 * Attempt to configure the interrupts using the best available
 * capabilities of the hardware and the kernel.
 **/
static int ixgbe_set_interrupt_capability(struct ixgbe_adapter *adapter)
{
	struct ixgbe_hw *hw = &adapter->hw;
	int err = 0;
	int vector, v_budget;

	/*
	 * It's easy to be greedy for MSI-X vectors, but it really
	 * doesn't do us much good if we have a lot more vectors
	 * than CPU's.  So let's be conservative and only ask for
	 * (roughly) the same number of vectors as there are CPU's.
	 * The default is to use pairs of vectors.
	 */
	v_budget = max(adapter->num_rx_queues, adapter->num_tx_queues);
	v_budget = min_t(int, v_budget, num_online_cpus());
	v_budget += NON_Q_VECTORS;

	/*
	 * At the same time, hardware can only support a maximum of
	 * hw.mac->max_msix_vectors vectors.  With features
	 * such as RSS and VMDq, we can easily surpass the number of Rx and Tx
	 * descriptor queues supported by our device.  Thus, we cap it off in
	 * those rare cases where the cpu count also exceeds our vector limit.
	 */
	v_budget = min_t(int, v_budget, hw->mac.max_msix_vectors);

	/* A failure in MSI-X entry allocation isn't fatal, but it does
	 * mean we disable MSI-X capabilities of the adapter. */
	adapter->msix_entries = kcalloc(v_budget,
					sizeof(struct msix_entry), GFP_KERNEL);
	if (adapter->msix_entries) {
		for (vector = 0; vector < v_budget; vector++)
			adapter->msix_entries[vector].entry = vector;

		ixgbe_acquire_msix_vectors(adapter, v_budget);

		if (adapter->flags & IXGBE_FLAG_MSIX_ENABLED)
			goto out;
	}

	adapter->flags &= ~IXGBE_FLAG_DCB_ENABLED;
	adapter->flags &= ~IXGBE_FLAG_RSS_ENABLED;
	if (adapter->flags & IXGBE_FLAG_FDIR_HASH_CAPABLE) {
		e_err(probe,
		      "ATR is not supported while multiple "
		      "queues are disabled.  Disabling Flow Director\n");
	}
	adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;
	adapter->atr_sample_rate = 0;
	if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)
		ixgbe_disable_sriov(adapter);

	err = ixgbe_set_num_queues(adapter);
	if (err)
		return err;

	adapter->num_q_vectors = 1;

	err = pci_enable_msi(adapter->pdev);
	if (!err) {
		adapter->flags |= IXGBE_FLAG_MSI_ENABLED;
	} else {
		netif_printk(adapter, hw, KERN_DEBUG, adapter->netdev,
			     "Unable to allocate MSI interrupt, "
			     "falling back to legacy.  Error: %d\n", err);
		/* reset err */
		err = 0;
	}

out:
	return err;
}

/**
 * ixgbe_init_interrupt_scheme - Determine proper interrupt scheme
 * @adapter: board private structure to initialize
 *
 * We determine which interrupt scheme to use based on...
 * - Kernel support (MSI, MSI-X)
 *   - which can be user-defined (via MODULE_PARAM)
 * - Hardware queue count (num_*_queues)
 *   - defined by miscellaneous hardware support/features (RSS, etc.)
 **/
int ixgbe_init_interrupt_scheme(struct ixgbe_adapter *adapter)
{
	int err;

	/* Number of supported queues */
	err = ixgbe_set_num_queues(adapter);
	if (err)
		return err;

	err = ixgbe_set_interrupt_capability(adapter);
	if (err) {
		e_dev_err("Unable to setup interrupt capabilities\n");
		goto err_set_interrupt;
	}

	err = ixgbe_alloc_q_vectors(adapter);
	if (err) {
		e_dev_err("Unable to allocate memory for queue vectors\n");
		goto err_alloc_q_vectors;
	}

	ixgbe_cache_ring_register(adapter);

	e_dev_info("Multiqueue %s: Rx Queue count = %u, Tx Queue count = %u\n",
		   (adapter->num_rx_queues > 1) ? "Enabled" : "Disabled",
		   adapter->num_rx_queues, adapter->num_tx_queues);

	set_bit(__IXGBE_DOWN, &adapter->state);

	return 0;

err_alloc_q_vectors:
	ixgbe_reset_interrupt_capability(adapter);
err_set_interrupt:
	return err;
}

/**
 * ixgbe_clear_interrupt_scheme - Clear the current interrupt scheme settings
 * @adapter: board private structure to clear interrupt scheme on
 *
 * We go through and clear interrupt specific resources and reset the structure
 * to pre-load conditions
 **/
void ixgbe_clear_interrupt_scheme(struct ixgbe_adapter *adapter)
{
	adapter->num_tx_queues = 0;
	adapter->num_rx_queues = 0;

	ixgbe_free_q_vectors(adapter);
	ixgbe_reset_interrupt_capability(adapter);
}

void ixgbe_tx_ctxtdesc(struct ixgbe_ring *tx_ring, u32 vlan_macip_lens,
		       u32 fcoe_sof_eof, u32 type_tucmd, u32 mss_l4len_idx)
{
	struct ixgbe_adv_tx_context_desc *context_desc;
	u16 i = tx_ring->next_to_use;

	context_desc = IXGBE_TX_CTXTDESC(tx_ring, i);

	i++;
	tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;

	/* set bits to identify this as an advanced context descriptor */
	type_tucmd |= IXGBE_TXD_CMD_DEXT | IXGBE_ADVTXD_DTYP_CTXT;

	context_desc->vlan_macip_lens	= cpu_to_le32(vlan_macip_lens);
	context_desc->seqnum_seed	= cpu_to_le32(fcoe_sof_eof);
	context_desc->type_tucmd_mlhl	= cpu_to_le32(type_tucmd);
	context_desc->mss_l4len_idx	= cpu_to_le32(mss_l4len_idx);
}