ixgbe_lib.c

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

  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 <[email protected]>
  Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497

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

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

#ifdef CONFIG_IXGBE_DCB

static bool ixgbe_cache_ring_dcb_sriov(struct ixgbe_adapter *adapter)
{
#ifdef IXGBE_FCOE
    struct ixgbe_ring_feature *fcoe = &adapter->ring_feature[RING_F_FCOE];
#endif /* IXGBE_FCOE */
    struct ixgbe_ring_feature *vmdq = &adapter->ring_feature[RING_F_VMDQ];
    int i;
    u16 reg_idx;
    u8 tcs = netdev_get_num_tc(adapter->netdev);

    /* verify we have DCB queueing enabled before proceeding */
    if (tcs <= 1)
        return false;

    /* verify we have VMDq enabled before proceeding */
    if (!(adapter->flags & IXGBE_FLAG_SRIOV_ENABLED))
        return false;

    /* start at VMDq register offset for SR-IOV enabled setups */
    reg_idx = vmdq->offset * __ALIGN_MASK(1, ~vmdq->mask);
    for (i = 0; i < adapter->num_rx_queues; i++, reg_idx++) {
        /* If we are greater than indices move to next pool */
        if ((reg_idx & ~vmdq->mask) >= tcs)
            reg_idx = __ALIGN_MASK(reg_idx, ~vmdq->mask);
        adapter->rx_ring[i]->reg_idx = reg_idx;
    }

    reg_idx = vmdq->offset * __ALIGN_MASK(1, ~vmdq->mask);
    for (i = 0; i < adapter->num_tx_queues; i++, reg_idx++) {
        /* If we are greater than indices move to next pool */
        if ((reg_idx & ~vmdq->mask) >= tcs)
            reg_idx = __ALIGN_MASK(reg_idx, ~vmdq->mask);
        adapter->tx_ring[i]->reg_idx = reg_idx;
    }

#ifdef IXGBE_FCOE
    /* nothing to do if FCoE is disabled */
    if (!(adapter->flags & IXGBE_FLAG_FCOE_ENABLED))
        return true;

    /* The work is already done if the FCoE ring is shared */
    if (fcoe->offset < tcs)
        return true;

    /* The FCoE rings exist separately, we need to move their reg_idx */
    if (fcoe->indices) {
        u16 queues_per_pool = __ALIGN_MASK(1, ~vmdq->mask);
        u8 fcoe_tc = ixgbe_fcoe_get_tc(adapter);

        reg_idx = (vmdq->offset + vmdq->indices) * queues_per_pool;
        for (i = fcoe->offset; i < adapter->num_rx_queues; i++) {
            reg_idx = __ALIGN_MASK(reg_idx, ~vmdq->mask) + fcoe_tc;
            adapter->rx_ring[i]->reg_idx = reg_idx;
            reg_idx++;
        }

        reg_idx = (vmdq->offset + vmdq->indices) * queues_per_pool;
        for (i = fcoe->offset; i < adapter->num_tx_queues; i++) {
            reg_idx = __ALIGN_MASK(reg_idx, ~vmdq->mask) + fcoe_tc;
            adapter->tx_ring[i]->reg_idx = reg_idx;
            reg_idx++;
        }
    }

#endif /* IXGBE_FCOE */
    return true;
}

/* 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:
        /* TxQs/TC: 4   RxQs/TC: 8 */
        *tx = tc << 2; /* 0, 4,  8, 12, 16, 20, 24, 28 */
        *rx = tc << 3; /* 0, 8, 16, 24, 32, 40, 48, 56 */
        break;
    case ixgbe_mac_82599EB:
    case ixgbe_mac_X540:
        if (num_tcs > 4) {
            /*
             * TCs    : TC0/1 TC2/3 TC4-7
             * TxQs/TC:    32    16     8
             * RxQs/TC:    16    16    16
             */
            *rx = tc << 4;
            if (tc < 3)
                *tx = tc << 5;      /*   0,  32,  64 */
            else if (tc < 5)
                *tx = (tc + 2) << 4;    /*  80,  96 */
            else
                *tx = (tc + 8) << 3;    /* 104, 112, 120 */
        } else {
            /*
             * TCs    : TC0 TC1 TC2/3
             * TxQs/TC:  64  32    16
             * RxQs/TC:  32  32    32
             */
            *rx = tc << 5;
            if (tc < 2)
                *tx = tc << 6;      /*  0,  64 */
            else
                *tx = (tc + 4) << 4;    /* 96, 112 */
        }
    default:
        break;
    }
}

static bool ixgbe_cache_ring_dcb(struct ixgbe_adapter *adapter)
{
    struct net_device *dev = adapter->netdev;
    unsigned int tx_idx, rx_idx;
    int tc, offset, rss_i, i;
    u8 num_tcs = netdev_get_num_tc(dev);

    /* verify we have DCB queueing enabled before proceeding */
    if (num_tcs <= 1)
        return false;

    rss_i = adapter->ring_feature[RING_F_RSS].indices;

    for (tc = 0, offset = 0; tc < num_tcs; tc++, offset += rss_i) {
        ixgbe_get_first_reg_idx(adapter, tc, &tx_idx, &rx_idx);
        for (i = 0; i < rss_i; i++, tx_idx++, rx_idx++) {
            adapter->tx_ring[offset + i]->reg_idx = tx_idx;
            adapter->rx_ring[offset + i]->reg_idx = rx_idx;
            adapter->tx_ring[offset + i]->dcb_tc = tc;
            adapter->rx_ring[offset + i]->dcb_tc = tc;
        }
    }

    return true;
}

#endif

static bool ixgbe_cache_ring_sriov(struct ixgbe_adapter *adapter)
{
#ifdef IXGBE_FCOE
    struct ixgbe_ring_feature *fcoe = &adapter->ring_feature[RING_F_FCOE];
#endif /* IXGBE_FCOE */
    struct ixgbe_ring_feature *vmdq = &adapter->ring_feature[RING_F_VMDQ];
    struct ixgbe_ring_feature *rss = &adapter->ring_feature[RING_F_RSS];
    int i;
    u16 reg_idx;

    /* only proceed if VMDq is enabled */
    if (!(adapter->flags & IXGBE_FLAG_VMDQ_ENABLED))
        return false;

    /* start at VMDq register offset for SR-IOV enabled setups */
    reg_idx = vmdq->offset * __ALIGN_MASK(1, ~vmdq->mask);
    for (i = 0; i < adapter->num_rx_queues; i++, reg_idx++) {
#ifdef IXGBE_FCOE
        /* Allow first FCoE queue to be mapped as RSS */
        if (fcoe->offset && (i > fcoe->offset))
            break;
#endif
        /* If we are greater than indices move to next pool */
        if ((reg_idx & ~vmdq->mask) >= rss->indices)
            reg_idx = __ALIGN_MASK(reg_idx, ~vmdq->mask);
        adapter->rx_ring[i]->reg_idx = reg_idx;
    }

#ifdef IXGBE_FCOE
    /* FCoE uses a linear block of queues so just assigning 1:1 */
    for (; i < adapter->num_rx_queues; i++, reg_idx++)
        adapter->rx_ring[i]->reg_idx = reg_idx;

#endif
    reg_idx = vmdq->offset * __ALIGN_MASK(1, ~vmdq->mask);
    for (i = 0; i < adapter->num_tx_queues; i++, reg_idx++) {
#ifdef IXGBE_FCOE
        /* Allow first FCoE queue to be mapped as RSS */
        if (fcoe->offset && (i > fcoe->offset))
            break;
#endif
        /* If we are greater than indices move to next pool */
        if ((reg_idx & rss->mask) >= rss->indices)
            reg_idx = __ALIGN_MASK(reg_idx, ~vmdq->mask);
        adapter->tx_ring[i]->reg_idx = reg_idx;
    }

#ifdef IXGBE_FCOE
    /* FCoE uses a linear block of queues so just assigning 1:1 */
    for (; i < adapter->num_tx_queues; i++, reg_idx++)
        adapter->tx_ring[i]->reg_idx = reg_idx;

#endif

    return true;
}

static bool ixgbe_cache_ring_rss(struct ixgbe_adapter *adapter)
{
    int i;

    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;
}

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;

#ifdef CONFIG_IXGBE_DCB
    if (ixgbe_cache_ring_dcb_sriov(adapter))
        return;

    if (ixgbe_cache_ring_dcb(adapter))
        return;

#endif
    if (ixgbe_cache_ring_sriov(adapter))
        return;

    ixgbe_cache_ring_rss(adapter);
}

#define IXGBE_RSS_16Q_MASK  0xF
#define IXGBE_RSS_8Q_MASK   0x7
#define IXGBE_RSS_4Q_MASK   0x3
#define IXGBE_RSS_2Q_MASK   0x1
#define IXGBE_RSS_DISABLED_MASK 0x0

#ifdef CONFIG_IXGBE_DCB

static bool ixgbe_set_dcb_sriov_queues(struct ixgbe_adapter *adapter)
{
    int i;
    u16 vmdq_i = adapter->ring_feature[RING_F_VMDQ].limit;
    u16 vmdq_m = 0;
#ifdef IXGBE_FCOE
    u16 fcoe_i = 0;
#endif
    u8 tcs = netdev_get_num_tc(adapter->netdev);

    /* verify we have DCB queueing enabled before proceeding */
    if (tcs <= 1)
        return false;

    /* verify we have VMDq enabled before proceeding */
    if (!(adapter->flags & IXGBE_FLAG_SRIOV_ENABLED))
        return false;

    /* Add starting offset to total pool count */
    vmdq_i += adapter->ring_feature[RING_F_VMDQ].offset;

    /* 16 pools w/ 8 TC per pool */
    if (tcs > 4) {
        vmdq_i = min_t(u16, vmdq_i, 16);
        vmdq_m = IXGBE_82599_VMDQ_8Q_MASK;
    /* 32 pools w/ 4 TC per pool */
    } else {
        vmdq_i = min_t(u16, vmdq_i, 32);
        vmdq_m = IXGBE_82599_VMDQ_4Q_MASK;
    }

#ifdef IXGBE_FCOE
    /* queues in the remaining pools are available for FCoE */
    fcoe_i = (128 / __ALIGN_MASK(1, ~vmdq_m)) - vmdq_i;

#endif
    /* remove the starting offset from the pool count */
    vmdq_i -= adapter->ring_feature[RING_F_VMDQ].offset;

    /* save features for later use */
    adapter->ring_feature[RING_F_VMDQ].indices = vmdq_i;
    adapter->ring_feature[RING_F_VMDQ].mask = vmdq_m;

    /*
     * We do not support DCB, VMDq, and RSS all simultaneously
     * so we will disable RSS since it is the lowest priority
     */
    adapter->ring_feature[RING_F_RSS].indices = 1;
    adapter->ring_feature[RING_F_RSS].mask = IXGBE_RSS_DISABLED_MASK;

    /* disable ATR as it is not supported when VMDq is enabled */
    adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;

    adapter->num_rx_pools = vmdq_i;
    adapter->num_rx_queues_per_pool = tcs;

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

#ifdef IXGBE_FCOE
    if (adapter->flags & IXGBE_FLAG_FCOE_ENABLED) {
        struct ixgbe_ring_feature *fcoe;

        fcoe = &adapter->ring_feature[RING_F_FCOE];

        /* limit ourselves based on feature limits */
        fcoe_i = min_t(u16, fcoe_i, num_online_cpus());
        fcoe_i = min_t(u16, fcoe_i, fcoe->limit);

        if (fcoe_i) {
            /* alloc queues for FCoE separately */
            fcoe->indices = fcoe_i;
            fcoe->offset = vmdq_i * tcs;

            /* add queues to adapter */
            adapter->num_tx_queues += fcoe_i;
            adapter->num_rx_queues += fcoe_i;
        } else if (tcs > 1) {
            /* use queue belonging to FcoE TC */
            fcoe->indices = 1;
            fcoe->offset = ixgbe_fcoe_get_tc(adapter);
        } else {
            adapter->flags &= ~IXGBE_FLAG_FCOE_ENABLED;

            fcoe->indices = 0;
            fcoe->offset = 0;
        }
    }

#endif /* IXGBE_FCOE */
    /* configure TC to queue mapping */
    for (i = 0; i < tcs; i++)
        netdev_set_tc_queue(adapter->netdev, i, 1, i);

    return true;
}

static bool ixgbe_set_dcb_queues(struct ixgbe_adapter *adapter)
{
    struct net_device *dev = adapter->netdev;
    struct ixgbe_ring_feature *f;
    int rss_i, rss_m, i;
    int tcs;

    /* Map queue offset and counts onto allocated tx queues */
    tcs = netdev_get_num_tc(dev);

    /* verify we have DCB queueing enabled before proceeding */
    if (tcs <= 1)
        return false;

    /* determine the upper limit for our current DCB mode */
    rss_i = dev->num_tx_queues / tcs;
    if (adapter->hw.mac.type == ixgbe_mac_82598EB) {
        /* 8 TC w/ 4 queues per TC */
        rss_i = min_t(u16, rss_i, 4);
        rss_m = IXGBE_RSS_4Q_MASK;
    } else if (tcs > 4) {
        /* 8 TC w/ 8 queues per TC */
        rss_i = min_t(u16, rss_i, 8);
        rss_m = IXGBE_RSS_8Q_MASK;
    } else {
        /* 4 TC w/ 16 queues per TC */
        rss_i = min_t(u16, rss_i, 16);
        rss_m = IXGBE_RSS_16Q_MASK;
    }

    /* set RSS mask and indices */
    f = &adapter->ring_feature[RING_F_RSS];
    rss_i = min_t(int, rss_i, f->limit);
    f->indices = rss_i;
    f->mask = rss_m;

    /* disable ATR as it is not supported when multiple TCs are enabled */
    adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;

#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 tc = ixgbe_fcoe_get_tc(adapter);

        f = &adapter->ring_feature[RING_F_FCOE];
        f->indices = min_t(u16, rss_i, f->limit);
        f->offset = rss_i * tc;
    }

#endif /* IXGBE_FCOE */
    for (i = 0; i < tcs; i++)
        netdev_set_tc_queue(dev, i, rss_i, rss_i * i);

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

    return true;
}

#endif

static bool ixgbe_set_sriov_queues(struct ixgbe_adapter *adapter)
{
    u16 vmdq_i = adapter->ring_feature[RING_F_VMDQ].limit;
    u16 vmdq_m = 0;
    u16 rss_i = adapter->ring_feature[RING_F_RSS].limit;
    u16 rss_m = IXGBE_RSS_DISABLED_MASK;
#ifdef IXGBE_FCOE
    u16 fcoe_i = 0;
#endif

    /* only proceed if SR-IOV is enabled */
    if (!(adapter->flags & IXGBE_FLAG_SRIOV_ENABLED))
        return false;

    /* Add starting offset to total pool count */
    vmdq_i += adapter->ring_feature[RING_F_VMDQ].offset;

    /* double check we are limited to maximum pools */
    vmdq_i = min_t(u16, IXGBE_MAX_VMDQ_INDICES, vmdq_i);

    /* 64 pool mode with 2 queues per pool */
    if ((vmdq_i > 32) || (rss_i < 4)) {
        vmdq_m = IXGBE_82599_VMDQ_2Q_MASK;
        rss_m = IXGBE_RSS_2Q_MASK;
        rss_i = min_t(u16, rss_i, 2);
    /* 32 pool mode with 4 queues per pool */
    } else {
        vmdq_m = IXGBE_82599_VMDQ_4Q_MASK;
        rss_m = IXGBE_RSS_4Q_MASK;
        rss_i = 4;
    }

#ifdef IXGBE_FCOE
    /* queues in the remaining pools are available for FCoE */
    fcoe_i = 128 - (vmdq_i * __ALIGN_MASK(1, ~vmdq_m));

#endif
    /* remove the starting offset from the pool count */
    vmdq_i -= adapter->ring_feature[RING_F_VMDQ].offset;

    /* save features for later use */
    adapter->ring_feature[RING_F_VMDQ].indices = vmdq_i;
    adapter->ring_feature[RING_F_VMDQ].mask = vmdq_m;

    /* limit RSS based on user input and save for later use */
    adapter->ring_feature[RING_F_RSS].indices = rss_i;
    adapter->ring_feature[RING_F_RSS].mask = rss_m;

    adapter->num_rx_pools = vmdq_i;
    adapter->num_rx_queues_per_pool = rss_i;

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

    /* disable ATR as it is not supported when VMDq is enabled */
    adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;

#ifdef IXGBE_FCOE
    /*
     * FCoE can use rings from adjacent buffers to allow RSS
     * like behavior.  To account for this we need to add the
     * FCoE indices to the total ring count.
     */
    if (adapter->flags & IXGBE_FLAG_FCOE_ENABLED) {
        struct ixgbe_ring_feature *fcoe;

        fcoe = &adapter->ring_feature[RING_F_FCOE];

        /* limit ourselves based on feature limits */
        fcoe_i = min_t(u16, fcoe_i, fcoe->limit);

        if (vmdq_i > 1 && fcoe_i) {
            /* reserve no more than number of CPUs */
            fcoe_i = min_t(u16, fcoe_i, num_online_cpus());

            /* alloc queues for FCoE separately */
            fcoe->indices = fcoe_i;
            fcoe->offset = vmdq_i * rss_i;
        } else {
            /* merge FCoE queues with RSS queues */
            fcoe_i = min_t(u16, fcoe_i + rss_i, num_online_cpus());

            /* limit indices to rss_i if MSI-X is disabled */
            if (!(adapter->flags & IXGBE_FLAG_MSIX_ENABLED))
                fcoe_i = rss_i;

            /* attempt to reserve some queues for just FCoE */
            fcoe->indices = min_t(u16, fcoe_i, fcoe->limit);
            fcoe->offset = fcoe_i - fcoe->indices;

            fcoe_i -= rss_i;
        }

        /* add queues to adapter */
        adapter->num_tx_queues += fcoe_i;
        adapter->num_rx_queues += fcoe_i;
    }

#endif
    return true;
}

static bool ixgbe_set_rss_queues(struct ixgbe_adapter *adapter)
{
    struct ixgbe_ring_feature *f;
    u16 rss_i;

    /* 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 = IXGBE_RSS_16Q_MASK;

    /* disable ATR by default, it will be configured below */
    adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;

    /*
     * 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 (rss_i > 1 && adapter->atr_sample_rate) {
        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);

        if (!(adapter->flags & IXGBE_FLAG_FDIR_PERFECT_CAPABLE))
            adapter->flags |= IXGBE_FLAG_FDIR_HASH_CAPABLE;
    }

#ifdef IXGBE_FCOE
    /*
     * FCoE can exist on the same rings as standard network traffic
     * however it is preferred to avoid that if possible.  In order
     * to get the best performance we allocate as many FCoE queues
     * as we can and we place them at the end of the ring array to
     * avoid sharing queues with standard RSS on systems with 24 or
     * more CPUs.
     */
    if (adapter->flags & IXGBE_FLAG_FCOE_ENABLED) {
        struct net_device *dev = adapter->netdev;
        u16 fcoe_i;

        f = &adapter->ring_feature[RING_F_FCOE];

        /* merge FCoE queues with RSS queues */
        fcoe_i = min_t(u16, f->limit + rss_i, num_online_cpus());
        fcoe_i = min_t(u16, fcoe_i, dev->num_tx_queues);

        /* limit indices to rss_i if MSI-X is disabled */
        if (!(adapter->flags & IXGBE_FLAG_MSIX_ENABLED))
            fcoe_i = rss_i;

        /* attempt to reserve some queues for just FCoE */
        f->indices = min_t(u16, fcoe_i, f->limit);
        f->offset = fcoe_i - f->indices;
        rss_i = max_t(u16, fcoe_i, rss_i);
    }

#endif /* IXGBE_FCOE */
    adapter->num_rx_queues = rss_i;
    adapter->num_tx_queues = rss_i;

    return true;
}

static void 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;

#ifdef CONFIG_IXGBE_DCB
    if (ixgbe_set_dcb_sriov_queues(adapter))
        return;

    if (ixgbe_set_dcb_queues(adapter))
        return;

#endif
    if (ixgbe_set_sriov_queues(adapter))
        return;

    ixgbe_set_rss_queues(adapter);
}

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++;
}

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;
}

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);
}

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;
}

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);
    }
}

static void ixgbe_set_interrupt_capability(struct ixgbe_adapter *adapter)
{
    struct ixgbe_hw *hw = &adapter->hw;
    int vector, v_budget, err;

    /*
     * 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)
            return;
    }

    /* disable DCB if number of TCs exceeds 1 */
    if (netdev_get_num_tc(adapter->netdev) > 1) {
        e_err(probe, "num TCs exceeds number of queues - disabling DCB\n");
        netdev_reset_tc(adapter->netdev);

        if (adapter->hw.mac.type == ixgbe_mac_82598EB)
            adapter->hw.fc.requested_mode = adapter->last_lfc_mode;

        adapter->flags &= ~IXGBE_FLAG_DCB_ENABLED;
        adapter->temp_dcb_cfg.pfc_mode_enable = false;
        adapter->dcb_cfg.pfc_mode_enable = false;
    }
    adapter->dcb_cfg.num_tcs.pg_tcs = 1;
    adapter->dcb_cfg.num_tcs.pfc_tcs = 1;

    /* disable SR-IOV */
    ixgbe_disable_sriov(adapter);

    /* disable RSS */
    adapter->ring_feature[RING_F_RSS].limit = 1;

    ixgbe_set_num_queues(adapter);
    adapter->num_q_vectors = 1;

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

int ixgbe_init_interrupt_scheme(struct ixgbe_adapter *adapter)
{
    int err;

    /* Number of supported queues */
    ixgbe_set_num_queues(adapter);

    /* Set interrupt mode */
    ixgbe_set_interrupt_capability(adapter);

    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);
    return err;
}

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);
}