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ipath_cq.c

/*
 * Copyright (c) 2006, 2007 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/vmalloc.h>

#include "ipath_verbs.h"

/**
 * ipath_cq_enter - add a new entry to the completion queue
 * @cq: completion queue
 * @entry: work completion entry to add
 * @sig: true if @entry is a solicitated entry
 *
 * This may be called with qp->s_lock held.
 */
void ipath_cq_enter(struct ipath_cq *cq, struct ib_wc *entry, int solicited)
{
      struct ipath_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].imm_data = (__u32 __force)entry->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)) {
            cq->notify = IB_CQ_NONE;
            cq->triggered++;
            /*
             * This will cause send_complete() to be called in
             * another thread.
             */
            tasklet_hi_schedule(&cq->comptask);
      }

      spin_unlock_irqrestore(&cq->lock, flags);

      if (entry->status != IB_WC_SUCCESS)
            to_idev(cq->ibcq.device)->n_wqe_errs++;
}

/**
 * ipath_poll_cq - poll for work completion entries
 * @ibcq: the completion queue to poll
 * @num_entries: the maximum number of entries to return
 * @entry: pointer to array where work completions are placed
 *
 * Returns the number of completion entries polled.
 *
 * This may be called from interrupt context.  Also called by ib_poll_cq()
 * in the generic verbs code.
 */
int ipath_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *entry)
{
      struct ipath_cq *cq = to_icq(ibcq);
      struct ipath_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(unsigned long data)
{
      struct ipath_cq *cq = (struct ipath_cq *)data;

      /*
       * 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, tasklet_hi_schedule()
       * 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;

            cq->ibcq.comp_handler(&cq->ibcq, cq->ibcq.cq_context);

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

/**
 * ipath_create_cq - create a completion queue
 * @ibdev: the device this completion queue is attached to
 * @entries: the minimum size of the completion queue
 * @context: unused by the InfiniPath driver
 * @udata: unused by the InfiniPath driver
 *
 * Returns a pointer to the completion queue or negative errno values
 * for failure.
 *
 * Called by ib_create_cq() in the generic verbs code.
 */
struct ib_cq *ipath_create_cq(struct ib_device *ibdev, int entries, int comp_vector,
                        struct ib_ucontext *context,
                        struct ib_udata *udata)
{
      struct ipath_ibdev *dev = to_idev(ibdev);
      struct ipath_cq *cq;
      struct ipath_cq_wc *wc;
      struct ib_cq *ret;
      u32 sz;

      if (entries < 1 || entries > ib_ipath_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 ipath_mmap() for details.
       */
      if (udata && udata->outlen >= sizeof(__u64)) {
            int err;

            cq->ip = ipath_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_ipath_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);
      tasklet_init(&cq->comptask, send_complete, (unsigned long)cq);
      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;
}

/**
 * ipath_destroy_cq - destroy a completion queue
 * @ibcq: the completion queue to destroy.
 *
 * Returns 0 for success.
 *
 * Called by ib_destroy_cq() in the generic verbs code.
 */
int ipath_destroy_cq(struct ib_cq *ibcq)
{
      struct ipath_ibdev *dev = to_idev(ibcq->device);
      struct ipath_cq *cq = to_icq(ibcq);

      tasklet_kill(&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, ipath_release_mmap_info);
      else
            vfree(cq->queue);
      kfree(cq);

      return 0;
}

/**
 * ipath_req_notify_cq - change the notification type for a completion queue
 * @ibcq: the completion queue
 * @notify_flags: the type of notification to request
 *
 * Returns 0 for success.
 *
 * This may be called from interrupt context.  Also called by
 * ib_req_notify_cq() in the generic verbs code.
 */
int ipath_req_notify_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags notify_flags)
{
      struct ipath_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;
}

/**
 * ipath_resize_cq - change the size of the CQ
 * @ibcq: the completion queue
 *
 * Returns 0 for success.
 */
int ipath_resize_cq(struct ib_cq *ibcq, int cqe, struct ib_udata *udata)
{
      struct ipath_cq *cq = to_icq(ibcq);
      struct ipath_cq_wc *old_wc;
      struct ipath_cq_wc *wc;
      u32 head, tail, n;
      int ret;
      u32 sz;

      if (cqe < 1 || cqe > ib_ipath_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 = -EOVERFLOW;
            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 ipath_ibdev *dev = to_idev(ibcq->device);
            struct ipath_mmap_info *ip = cq->ip;

            ipath_update_mmap_info(dev, ip, sz, wc);

            /*
             * Return the offset to mmap.
             * See ipath_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;
}

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