qib_cq.c

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/*
 * Copyright (c) 2006, 2007, 2008, 2010 QLogic Corporation. All rights reserved.
 * Copyright (c) 2005, 2006 PathScale, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/err.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>

#include "qib_verbs.h"

void qib_cq_enter(struct qib_cq *cq, struct ib_wc *entry, int solicited)
{
    struct qib_cq_wc *wc;
    unsigned long flags;
    u32 head;
    u32 next;

    spin_lock_irqsave(&cq->lock, flags);

    /*
     * Note that the head pointer might be writable by user processes.
     * Take care to verify it is a sane value.
     */
    wc = cq->queue;
    head = wc->head;
    if (head >= (unsigned) cq->ibcq.cqe) {
        head = cq->ibcq.cqe;
        next = 0;
    } else
        next = head + 1;
    if (unlikely(next == wc->tail)) {
        spin_unlock_irqrestore(&cq->lock, flags);
        if (cq->ibcq.event_handler) {
            struct ib_event ev;

            ev.device = cq->ibcq.device;
            ev.element.cq = &cq->ibcq;
            ev.event = IB_EVENT_CQ_ERR;
            cq->ibcq.event_handler(&ev, cq->ibcq.cq_context);
        }
        return;
    }
    if (cq->ip) {
        wc->uqueue[head].wr_id = entry->wr_id;
        wc->uqueue[head].status = entry->status;
        wc->uqueue[head].opcode = entry->opcode;
        wc->uqueue[head].vendor_err = entry->vendor_err;
        wc->uqueue[head].byte_len = entry->byte_len;
        wc->uqueue[head].ex.imm_data =
            (__u32 __force)entry->ex.imm_data;
        wc->uqueue[head].qp_num = entry->qp->qp_num;
        wc->uqueue[head].src_qp = entry->src_qp;
        wc->uqueue[head].wc_flags = entry->wc_flags;
        wc->uqueue[head].pkey_index = entry->pkey_index;
        wc->uqueue[head].slid = entry->slid;
        wc->uqueue[head].sl = entry->sl;
        wc->uqueue[head].dlid_path_bits = entry->dlid_path_bits;
        wc->uqueue[head].port_num = entry->port_num;
        /* Make sure entry is written before the head index. */
        smp_wmb();
    } else
        wc->kqueue[head] = *entry;
    wc->head = next;

    if (cq->notify == IB_CQ_NEXT_COMP ||
        (cq->notify == IB_CQ_SOLICITED &&
         (solicited || entry->status != IB_WC_SUCCESS))) {
        cq->notify = IB_CQ_NONE;
        cq->triggered++;
        /*
         * This will cause send_complete() to be called in
         * another thread.
         */
        queue_work(qib_cq_wq, &cq->comptask);
    }

    spin_unlock_irqrestore(&cq->lock, flags);
}

int qib_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
{
    struct qib_cq *cq = to_icq(ibcq);
    struct qib_cq_wc *wc;
    unsigned long flags;
    int npolled;
    u32 tail;

    /* The kernel can only poll a kernel completion queue */
    if (cq->ip) {
        npolled = -EINVAL;
        goto bail;
    }

    spin_lock_irqsave(&cq->lock, flags);

    wc = cq->queue;
    tail = wc->tail;
    if (tail > (u32) cq->ibcq.cqe)
        tail = (u32) cq->ibcq.cqe;
    for (npolled = 0; npolled < num_entries; ++npolled, ++entry) {
        if (tail == wc->head)
            break;
        /* The kernel doesn't need a RMB since it has the lock. */
        *entry = wc->kqueue[tail];
        if (tail >= cq->ibcq.cqe)
            tail = 0;
        else
            tail++;
    }
    wc->tail = tail;

    spin_unlock_irqrestore(&cq->lock, flags);

bail:
    return npolled;
}

static void send_complete(struct work_struct *work)
{
    struct qib_cq *cq = container_of(work, struct qib_cq, comptask);

    /*
     * The completion handler will most likely rearm the notification
     * and poll for all pending entries.  If a new completion entry
     * is added while we are in this routine, queue_work()
     * won't call us again until we return so we check triggered to
     * see if we need to call the handler again.
     */
    for (;;) {
        u8 triggered = cq->triggered;

        /*
         * IPoIB connected mode assumes the callback is from a
         * soft IRQ. We simulate this by blocking "bottom halves".
         * See the implementation for ipoib_cm_handle_tx_wc(),
         * netif_tx_lock_bh() and netif_tx_lock().
         */
        local_bh_disable();
        cq->ibcq.comp_handler(&cq->ibcq, cq->ibcq.cq_context);
        local_bh_enable();

        if (cq->triggered == triggered)
            return;
    }
}

struct ib_cq *qib_create_cq(struct ib_device *ibdev, int entries,
                int comp_vector, struct ib_ucontext *context,
                struct ib_udata *udata)
{
    struct qib_ibdev *dev = to_idev(ibdev);
    struct qib_cq *cq;
    struct qib_cq_wc *wc;
    struct ib_cq *ret;
    u32 sz;

    if (entries < 1 || entries > ib_qib_max_cqes) {
        ret = ERR_PTR(-EINVAL);
        goto done;
    }

    /* Allocate the completion queue structure. */
    cq = kmalloc(sizeof(*cq), GFP_KERNEL);
    if (!cq) {
        ret = ERR_PTR(-ENOMEM);
        goto done;
    }

    /*
     * Allocate the completion queue entries and head/tail pointers.
     * This is allocated separately so that it can be resized and
     * also mapped into user space.
     * We need to use vmalloc() in order to support mmap and large
     * numbers of entries.
     */
    sz = sizeof(*wc);
    if (udata && udata->outlen >= sizeof(__u64))
        sz += sizeof(struct ib_uverbs_wc) * (entries + 1);
    else
        sz += sizeof(struct ib_wc) * (entries + 1);
    wc = vmalloc_user(sz);
    if (!wc) {
        ret = ERR_PTR(-ENOMEM);
        goto bail_cq;
    }

    /*
     * Return the address of the WC as the offset to mmap.
     * See qib_mmap() for details.
     */
    if (udata && udata->outlen >= sizeof(__u64)) {
        int err;

        cq->ip = qib_create_mmap_info(dev, sz, context, wc);
        if (!cq->ip) {
            ret = ERR_PTR(-ENOMEM);
            goto bail_wc;
        }

        err = ib_copy_to_udata(udata, &cq->ip->offset,
                       sizeof(cq->ip->offset));
        if (err) {
            ret = ERR_PTR(err);
            goto bail_ip;
        }
    } else
        cq->ip = NULL;

    spin_lock(&dev->n_cqs_lock);
    if (dev->n_cqs_allocated == ib_qib_max_cqs) {
        spin_unlock(&dev->n_cqs_lock);
        ret = ERR_PTR(-ENOMEM);
        goto bail_ip;
    }

    dev->n_cqs_allocated++;
    spin_unlock(&dev->n_cqs_lock);

    if (cq->ip) {
        spin_lock_irq(&dev->pending_lock);
        list_add(&cq->ip->pending_mmaps, &dev->pending_mmaps);
        spin_unlock_irq(&dev->pending_lock);
    }

    /*
     * ib_create_cq() will initialize cq->ibcq except for cq->ibcq.cqe.
     * The number of entries should be >= the number requested or return
     * an error.
     */
    cq->ibcq.cqe = entries;
    cq->notify = IB_CQ_NONE;
    cq->triggered = 0;
    spin_lock_init(&cq->lock);
    INIT_WORK(&cq->comptask, send_complete);
    wc->head = 0;
    wc->tail = 0;
    cq->queue = wc;

    ret = &cq->ibcq;

    goto done;

bail_ip:
    kfree(cq->ip);
bail_wc:
    vfree(wc);
bail_cq:
    kfree(cq);
done:
    return ret;
}

int qib_destroy_cq(struct ib_cq *ibcq)
{
    struct qib_ibdev *dev = to_idev(ibcq->device);
    struct qib_cq *cq = to_icq(ibcq);

    flush_work(&cq->comptask);
    spin_lock(&dev->n_cqs_lock);
    dev->n_cqs_allocated--;
    spin_unlock(&dev->n_cqs_lock);
    if (cq->ip)
        kref_put(&cq->ip->ref, qib_release_mmap_info);
    else
        vfree(cq->queue);
    kfree(cq);

    return 0;
}

int qib_req_notify_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags notify_flags)
{
    struct qib_cq *cq = to_icq(ibcq);
    unsigned long flags;
    int ret = 0;

    spin_lock_irqsave(&cq->lock, flags);
    /*
     * Don't change IB_CQ_NEXT_COMP to IB_CQ_SOLICITED but allow
     * any other transitions (see C11-31 and C11-32 in ch. 11.4.2.2).
     */
    if (cq->notify != IB_CQ_NEXT_COMP)
        cq->notify = notify_flags & IB_CQ_SOLICITED_MASK;

    if ((notify_flags & IB_CQ_REPORT_MISSED_EVENTS) &&
        cq->queue->head != cq->queue->tail)
        ret = 1;

    spin_unlock_irqrestore(&cq->lock, flags);

    return ret;
}

int qib_resize_cq(struct ib_cq *ibcq, int cqe, struct ib_udata *udata)
{
    struct qib_cq *cq = to_icq(ibcq);
    struct qib_cq_wc *old_wc;
    struct qib_cq_wc *wc;
    u32 head, tail, n;
    int ret;
    u32 sz;

    if (cqe < 1 || cqe > ib_qib_max_cqes) {
        ret = -EINVAL;
        goto bail;
    }

    /*
     * Need to use vmalloc() if we want to support large #s of entries.
     */
    sz = sizeof(*wc);
    if (udata && udata->outlen >= sizeof(__u64))
        sz += sizeof(struct ib_uverbs_wc) * (cqe + 1);
    else
        sz += sizeof(struct ib_wc) * (cqe + 1);
    wc = vmalloc_user(sz);
    if (!wc) {
        ret = -ENOMEM;
        goto bail;
    }

    /* Check that we can write the offset to mmap. */
    if (udata && udata->outlen >= sizeof(__u64)) {
        __u64 offset = 0;

        ret = ib_copy_to_udata(udata, &offset, sizeof(offset));
        if (ret)
            goto bail_free;
    }

    spin_lock_irq(&cq->lock);
    /*
     * Make sure head and tail are sane since they
     * might be user writable.
     */
    old_wc = cq->queue;
    head = old_wc->head;
    if (head > (u32) cq->ibcq.cqe)
        head = (u32) cq->ibcq.cqe;
    tail = old_wc->tail;
    if (tail > (u32) cq->ibcq.cqe)
        tail = (u32) cq->ibcq.cqe;
    if (head < tail)
        n = cq->ibcq.cqe + 1 + head - tail;
    else
        n = head - tail;
    if (unlikely((u32)cqe < n)) {
        ret = -EINVAL;
        goto bail_unlock;
    }
    for (n = 0; tail != head; n++) {
        if (cq->ip)
            wc->uqueue[n] = old_wc->uqueue[tail];
        else
            wc->kqueue[n] = old_wc->kqueue[tail];
        if (tail == (u32) cq->ibcq.cqe)
            tail = 0;
        else
            tail++;
    }
    cq->ibcq.cqe = cqe;
    wc->head = n;
    wc->tail = 0;
    cq->queue = wc;
    spin_unlock_irq(&cq->lock);

    vfree(old_wc);

    if (cq->ip) {
        struct qib_ibdev *dev = to_idev(ibcq->device);
        struct qib_mmap_info *ip = cq->ip;

        qib_update_mmap_info(dev, ip, sz, wc);

        /*
         * Return the offset to mmap.
         * See qib_mmap() for details.
         */
        if (udata && udata->outlen >= sizeof(__u64)) {
            ret = ib_copy_to_udata(udata, &ip->offset,
                           sizeof(ip->offset));
            if (ret)
                goto bail;
        }

        spin_lock_irq(&dev->pending_lock);
        if (list_empty(&ip->pending_mmaps))
            list_add(&ip->pending_mmaps, &dev->pending_mmaps);
        spin_unlock_irq(&dev->pending_lock);
    }

    ret = 0;
    goto bail;

bail_unlock:
    spin_unlock_irq(&cq->lock);
bail_free:
    vfree(wc);
bail:
    return ret;
}