qib_keys.c

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/*
 * Copyright (c) 2006, 2007, 2009 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 "qib.h"

int qib_alloc_lkey(struct qib_mregion *mr, int dma_region)
{
    unsigned long flags;
    u32 r;
    u32 n;
    int ret = 0;
    struct qib_ibdev *dev = to_idev(mr->pd->device);
    struct qib_lkey_table *rkt = &dev->lk_table;

    spin_lock_irqsave(&rkt->lock, flags);

    /* special case for dma_mr lkey == 0 */
    if (dma_region) {
        struct qib_mregion *tmr;

        tmr = rcu_dereference(dev->dma_mr);
        if (!tmr) {
            qib_get_mr(mr);
            rcu_assign_pointer(dev->dma_mr, mr);
            mr->lkey_published = 1;
        }
        goto success;
    }

    /* Find the next available LKEY */
    r = rkt->next;
    n = r;
    for (;;) {
        if (rkt->table[r] == NULL)
            break;
        r = (r + 1) & (rkt->max - 1);
        if (r == n)
            goto bail;
    }
    rkt->next = (r + 1) & (rkt->max - 1);
    /*
     * Make sure lkey is never zero which is reserved to indicate an
     * unrestricted LKEY.
     */
    rkt->gen++;
    mr->lkey = (r << (32 - ib_qib_lkey_table_size)) |
        ((((1 << (24 - ib_qib_lkey_table_size)) - 1) & rkt->gen)
         << 8);
    if (mr->lkey == 0) {
        mr->lkey |= 1 << 8;
        rkt->gen++;
    }
    qib_get_mr(mr);
    rcu_assign_pointer(rkt->table[r], mr);
    mr->lkey_published = 1;
success:
    spin_unlock_irqrestore(&rkt->lock, flags);
out:
    return ret;
bail:
    spin_unlock_irqrestore(&rkt->lock, flags);
    ret = -ENOMEM;
    goto out;
}

void qib_free_lkey(struct qib_mregion *mr)
{
    unsigned long flags;
    u32 lkey = mr->lkey;
    u32 r;
    struct qib_ibdev *dev = to_idev(mr->pd->device);
    struct qib_lkey_table *rkt = &dev->lk_table;

    spin_lock_irqsave(&rkt->lock, flags);
    if (!mr->lkey_published)
        goto out;
    if (lkey == 0)
        rcu_assign_pointer(dev->dma_mr, NULL);
    else {
        r = lkey >> (32 - ib_qib_lkey_table_size);
        rcu_assign_pointer(rkt->table[r], NULL);
    }
    qib_put_mr(mr);
    mr->lkey_published = 0;
out:
    spin_unlock_irqrestore(&rkt->lock, flags);
}

int qib_lkey_ok(struct qib_lkey_table *rkt, struct qib_pd *pd,
        struct qib_sge *isge, struct ib_sge *sge, int acc)
{
    struct qib_mregion *mr;
    unsigned n, m;
    size_t off;

    /*
     * We use LKEY == zero for kernel virtual addresses
     * (see qib_get_dma_mr and qib_dma.c).
     */
    rcu_read_lock();
    if (sge->lkey == 0) {
        struct qib_ibdev *dev = to_idev(pd->ibpd.device);

        if (pd->user)
            goto bail;
        mr = rcu_dereference(dev->dma_mr);
        if (!mr)
            goto bail;
        if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
            goto bail;
        rcu_read_unlock();

        isge->mr = mr;
        isge->vaddr = (void *) sge->addr;
        isge->length = sge->length;
        isge->sge_length = sge->length;
        isge->m = 0;
        isge->n = 0;
        goto ok;
    }
    mr = rcu_dereference(
        rkt->table[(sge->lkey >> (32 - ib_qib_lkey_table_size))]);
    if (unlikely(!mr || mr->lkey != sge->lkey || mr->pd != &pd->ibpd))
        goto bail;

    off = sge->addr - mr->user_base;
    if (unlikely(sge->addr < mr->user_base ||
             off + sge->length > mr->length ||
             (mr->access_flags & acc) != acc))
        goto bail;
    if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
        goto bail;
    rcu_read_unlock();

    off += mr->offset;
    if (mr->page_shift) {
        /*
        page sizes are uniform power of 2 so no loop is necessary
        entries_spanned_by_off is the number of times the loop below
        would have executed.
        */
        size_t entries_spanned_by_off;

        entries_spanned_by_off = off >> mr->page_shift;
        off -= (entries_spanned_by_off << mr->page_shift);
        m = entries_spanned_by_off/QIB_SEGSZ;
        n = entries_spanned_by_off%QIB_SEGSZ;
    } else {
        m = 0;
        n = 0;
        while (off >= mr->map[m]->segs[n].length) {
            off -= mr->map[m]->segs[n].length;
            n++;
            if (n >= QIB_SEGSZ) {
                m++;
                n = 0;
            }
        }
    }
    isge->mr = mr;
    isge->vaddr = mr->map[m]->segs[n].vaddr + off;
    isge->length = mr->map[m]->segs[n].length - off;
    isge->sge_length = sge->length;
    isge->m = m;
    isge->n = n;
ok:
    return 1;
bail:
    rcu_read_unlock();
    return 0;
}

int qib_rkey_ok(struct qib_qp *qp, struct qib_sge *sge,
        u32 len, u64 vaddr, u32 rkey, int acc)
{
    struct qib_lkey_table *rkt = &to_idev(qp->ibqp.device)->lk_table;
    struct qib_mregion *mr;
    unsigned n, m;
    size_t off;

    /*
     * We use RKEY == zero for kernel virtual addresses
     * (see qib_get_dma_mr and qib_dma.c).
     */
    rcu_read_lock();
    if (rkey == 0) {
        struct qib_pd *pd = to_ipd(qp->ibqp.pd);
        struct qib_ibdev *dev = to_idev(pd->ibpd.device);

        if (pd->user)
            goto bail;
        mr = rcu_dereference(dev->dma_mr);
        if (!mr)
            goto bail;
        if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
            goto bail;
        rcu_read_unlock();

        sge->mr = mr;
        sge->vaddr = (void *) vaddr;
        sge->length = len;
        sge->sge_length = len;
        sge->m = 0;
        sge->n = 0;
        goto ok;
    }

    mr = rcu_dereference(
        rkt->table[(rkey >> (32 - ib_qib_lkey_table_size))]);
    if (unlikely(!mr || mr->lkey != rkey || qp->ibqp.pd != mr->pd))
        goto bail;

    off = vaddr - mr->iova;
    if (unlikely(vaddr < mr->iova || off + len > mr->length ||
             (mr->access_flags & acc) == 0))
        goto bail;
    if (unlikely(!atomic_inc_not_zero(&mr->refcount)))
        goto bail;
    rcu_read_unlock();

    off += mr->offset;
    if (mr->page_shift) {
        /*
        page sizes are uniform power of 2 so no loop is necessary
        entries_spanned_by_off is the number of times the loop below
        would have executed.
        */
        size_t entries_spanned_by_off;

        entries_spanned_by_off = off >> mr->page_shift;
        off -= (entries_spanned_by_off << mr->page_shift);
        m = entries_spanned_by_off/QIB_SEGSZ;
        n = entries_spanned_by_off%QIB_SEGSZ;
    } else {
        m = 0;
        n = 0;
        while (off >= mr->map[m]->segs[n].length) {
            off -= mr->map[m]->segs[n].length;
            n++;
            if (n >= QIB_SEGSZ) {
                m++;
                n = 0;
            }
        }
    }
    sge->mr = mr;
    sge->vaddr = mr->map[m]->segs[n].vaddr + off;
    sge->length = mr->map[m]->segs[n].length - off;
    sge->sge_length = len;
    sge->m = m;
    sge->n = n;
ok:
    return 1;
bail:
    rcu_read_unlock();
    return 0;
}

/*
 * Initialize the memory region specified by the work reqeust.
 */
int qib_fast_reg_mr(struct qib_qp *qp, struct ib_send_wr *wr)
{
    struct qib_lkey_table *rkt = &to_idev(qp->ibqp.device)->lk_table;
    struct qib_pd *pd = to_ipd(qp->ibqp.pd);
    struct qib_mregion *mr;
    u32 rkey = wr->wr.fast_reg.rkey;
    unsigned i, n, m;
    int ret = -EINVAL;
    unsigned long flags;
    u64 *page_list;
    size_t ps;

    spin_lock_irqsave(&rkt->lock, flags);
    if (pd->user || rkey == 0)
        goto bail;

    mr = rcu_dereference_protected(
        rkt->table[(rkey >> (32 - ib_qib_lkey_table_size))],
        lockdep_is_held(&rkt->lock));
    if (unlikely(mr == NULL || qp->ibqp.pd != mr->pd))
        goto bail;

    if (wr->wr.fast_reg.page_list_len > mr->max_segs)
        goto bail;

    ps = 1UL << wr->wr.fast_reg.page_shift;
    if (wr->wr.fast_reg.length > ps * wr->wr.fast_reg.page_list_len)
        goto bail;

    mr->user_base = wr->wr.fast_reg.iova_start;
    mr->iova = wr->wr.fast_reg.iova_start;
    mr->lkey = rkey;
    mr->length = wr->wr.fast_reg.length;
    mr->access_flags = wr->wr.fast_reg.access_flags;
    page_list = wr->wr.fast_reg.page_list->page_list;
    m = 0;
    n = 0;
    for (i = 0; i < wr->wr.fast_reg.page_list_len; i++) {
        mr->map[m]->segs[n].vaddr = (void *) page_list[i];
        mr->map[m]->segs[n].length = ps;
        if (++n == QIB_SEGSZ) {
            m++;
            n = 0;
        }
    }

    ret = 0;
bail:
    spin_unlock_irqrestore(&rkt->lock, flags);
    return ret;
}