drivers/infiniband/core/cq.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2015 HGST, a Western Digital Company.
  */
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <rdma/ib_verbs.h>

 #include "core_priv.h"

 #include <trace/events/rdma_core.h>
 /* Max size for shared CQ, may require tuning */
 #define IB_MAX_SHARED_CQ_SZ		4096U

 /* # of WCs to poll for with a single call to ib_poll_cq */
 #define IB_POLL_BATCH			16
 #define IB_POLL_BATCH_DIRECT		8

 /* # of WCs to iterate over before yielding */
 #define IB_POLL_BUDGET_IRQ		256
 #define IB_POLL_BUDGET_WORKQUEUE	65536

 #define IB_POLL_FLAGS \
 	(IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS)

 static const struct dim_cq_moder
 rdma_dim_prof[RDMA_DIM_PARAMS_NUM_PROFILES] = {
 	{1,   0, 1,  0},
 	{1,   0, 4,  0},
 	{2,   0, 4,  0},
 	{2,   0, 8,  0},
 	{4,   0, 8,  0},
 	{16,  0, 8,  0},
 	{16,  0, 16, 0},
 	{32,  0, 16, 0},
 	{32,  0, 32, 0},
 };

 static void ib_cq_rdma_dim_work(struct work_struct *w)
 {
 	struct dim *dim = container_of(w, struct dim, work);
 	struct ib_cq *cq = dim->priv;

 	u16 usec = rdma_dim_prof[dim->profile_ix].usec;
 	u16 comps = rdma_dim_prof[dim->profile_ix].comps;

 	dim->state = DIM_START_MEASURE;

 	trace_cq_modify(cq, comps, usec);
 	cq->device->ops.modify_cq(cq, comps, usec);
 }

 static void rdma_dim_init(struct ib_cq *cq)
 {
 	struct dim *dim;

 	if (!cq->device->ops.modify_cq || !cq->device->use_cq_dim ||
 	    cq->poll_ctx == IB_POLL_DIRECT)
 		return;

 	dim = kzalloc(sizeof(struct dim), GFP_KERNEL);
 	if (!dim)
 		return;

 	dim->state = DIM_START_MEASURE;
 	dim->tune_state = DIM_GOING_RIGHT;
 	dim->profile_ix = RDMA_DIM_START_PROFILE;
 	dim->priv = cq;
 	cq->dim = dim;

 	INIT_WORK(&dim->work, ib_cq_rdma_dim_work);
 }

 static void rdma_dim_destroy(struct ib_cq *cq)
 {
 	if (!cq->dim)
 		return;

 	cancel_work_sync(&cq->dim->work);
 	kfree(cq->dim);
 }

 static int __poll_cq(struct ib_cq *cq, int num_entries, struct ib_wc *wc)
 {
 	int rc;

 	rc = ib_poll_cq(cq, num_entries, wc);
 	trace_cq_poll(cq, num_entries, rc);
 	return rc;
 }

 static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *wcs,
 			   int batch)
 {
 	int i, n, completed = 0;

 	trace_cq_process(cq);

 	/*
 	 * budget might be (-1) if the caller does not
 	 * want to bound this call, thus we need unsigned
 	 * minimum here.
 	 */
 	while ((n = __poll_cq(cq, min_t(u32, batch,
 					budget - completed), wcs)) > 0) {
 		for (i = 0; i < n; i++) {
 			struct ib_wc *wc = &wcs[i];

 			if (wc->wr_cqe)
 				wc->wr_cqe->done(cq, wc);
 			else
 				WARN_ON_ONCE(wc->status == IB_WC_SUCCESS);
 		}

 		completed += n;

 		if (n != batch || (budget != -1 && completed >= budget))
 			break;
 	}

 	return completed;
 }

 /**
  * ib_process_cq_direct - process a CQ in caller context
  * @cq:		CQ to process
  * @budget:	number of CQEs to poll for
  *
  * This function is used to process all outstanding CQ entries.
  * It does not offload CQ processing to a different context and does
  * not ask for completion interrupts from the HCA.
  * Using direct processing on CQ with non IB_POLL_DIRECT type may trigger
  * concurrent processing.
  *
  * Note: do not pass -1 as %budget unless it is guaranteed that the number
  * of completions that will be processed is small.
  */
 int ib_process_cq_direct(struct ib_cq *cq, int budget)
 {
 	struct ib_wc wcs[IB_POLL_BATCH_DIRECT];

 	return __ib_process_cq(cq, budget, wcs, IB_POLL_BATCH_DIRECT);
 }
 EXPORT_SYMBOL(ib_process_cq_direct);

 static void ib_cq_completion_direct(struct ib_cq *cq, void *private)
 {
 	WARN_ONCE(1, "got unsolicited completion for CQ 0x%p\n", cq);
 }

 static int ib_poll_handler(struct irq_poll *iop, int budget)
 {
 	struct ib_cq *cq = container_of(iop, struct ib_cq, iop);
 	struct dim *dim = cq->dim;
 	int completed;

 	completed = __ib_process_cq(cq, budget, cq->wc, IB_POLL_BATCH);
 	if (completed < budget) {
 		irq_poll_complete(&cq->iop);
 		if (ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0) {
 			trace_cq_reschedule(cq);
 			irq_poll_sched(&cq->iop);
 		}
 	}

 	if (dim)
 		rdma_dim(dim, completed);

 	return completed;
 }

 static void ib_cq_completion_softirq(struct ib_cq *cq, void *private)
 {
 	trace_cq_schedule(cq);
 	irq_poll_sched(&cq->iop);
 }

 static void ib_cq_poll_work(struct work_struct *work)
 {
 	struct ib_cq *cq = container_of(work, struct ib_cq, work);
 	int completed;

 	completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE, cq->wc,
 				    IB_POLL_BATCH);
 	if (completed >= IB_POLL_BUDGET_WORKQUEUE ||
 	    ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0)
 		queue_work(cq->comp_wq, &cq->work);
 	else if (cq->dim)
 		rdma_dim(cq->dim, completed);
 }

 static void ib_cq_completion_workqueue(struct ib_cq *cq, void *private)
 {
 	trace_cq_schedule(cq);
 	queue_work(cq->comp_wq, &cq->work);
 }

 /**
  * __ib_alloc_cq - allocate a completion queue
  * @dev:		device to allocate the CQ for
  * @private:		driver private data, accessible from cq->cq_context
  * @nr_cqe:		number of CQEs to allocate
  * @comp_vector:	HCA completion vectors for this CQ
  * @poll_ctx:		context to poll the CQ from.
  * @caller:		module owner name.
  *
  * This is the proper interface to allocate a CQ for in-kernel users. A
  * CQ allocated with this interface will automatically be polled from the
  * specified context. The ULP must use wr->wr_cqe instead of wr->wr_id
  * to use this CQ abstraction.
  */
 struct ib_cq *__ib_alloc_cq(struct ib_device *dev, void *private, int nr_cqe,
 			    int comp_vector, enum ib_poll_context poll_ctx,
 			    const char *caller)
 {
 	struct ib_cq_init_attr cq_attr = {
 		.cqe		= nr_cqe,
 		.comp_vector	= comp_vector,
 	};
 	struct ib_cq *cq;
 	int ret = -ENOMEM;

 	cq = rdma_zalloc_drv_obj(dev, ib_cq);
 	if (!cq)
 		return ERR_PTR(ret);

 	cq->device = dev;
 	cq->cq_context = private;
 	cq->poll_ctx = poll_ctx;
 	atomic_set(&cq->usecnt, 0);
 	cq->comp_vector = comp_vector;

 	cq->wc = kmalloc_array(IB_POLL_BATCH, sizeof(*cq->wc), GFP_KERNEL);
 	if (!cq->wc)
 		goto out_free_cq;

 	rdma_restrack_new(&cq->res, RDMA_RESTRACK_CQ);
 	rdma_restrack_set_name(&cq->res, caller);

 	ret = dev->ops.create_cq(cq, &cq_attr, NULL);
 	if (ret)
 		goto out_free_wc;

 	rdma_dim_init(cq);

 	switch (cq->poll_ctx) {
 	case IB_POLL_DIRECT:
 		cq->comp_handler = ib_cq_completion_direct;
 		break;
 	case IB_POLL_SOFTIRQ:
 		cq->comp_handler = ib_cq_completion_softirq;

 		irq_poll_init(&cq->iop, IB_POLL_BUDGET_IRQ, ib_poll_handler);
 		ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
 		break;
 	case IB_POLL_WORKQUEUE:
 	case IB_POLL_UNBOUND_WORKQUEUE:
 		cq->comp_handler = ib_cq_completion_workqueue;
 		INIT_WORK(&cq->work, ib_cq_poll_work);
 		ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
 		cq->comp_wq = (cq->poll_ctx == IB_POLL_WORKQUEUE) ?
 				ib_comp_wq : ib_comp_unbound_wq;
 		break;
 	default:
 		ret = -EINVAL;
 		goto out_destroy_cq;
 	}

 	rdma_restrack_add(&cq->res);
 	trace_cq_alloc(cq, nr_cqe, comp_vector, poll_ctx);
 	return cq;

 out_destroy_cq:
 	rdma_dim_destroy(cq);
 	cq->device->ops.destroy_cq(cq, NULL);
 out_free_wc:
 	rdma_restrack_put(&cq->res);
 	kfree(cq->wc);
 out_free_cq:
 	kfree(cq);
 	trace_cq_alloc_error(nr_cqe, comp_vector, poll_ctx, ret);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(__ib_alloc_cq);

 /**
  * __ib_alloc_cq_any - allocate a completion queue
  * @dev:		device to allocate the CQ for
  * @private:		driver private data, accessible from cq->cq_context
  * @nr_cqe:		number of CQEs to allocate
  * @poll_ctx:		context to poll the CQ from
  * @caller:		module owner name
  *
  * Attempt to spread ULP Completion Queues over each device's interrupt
  * vectors. A simple best-effort mechanism is used.
  */
 struct ib_cq *__ib_alloc_cq_any(struct ib_device *dev, void *private,
 				int nr_cqe, enum ib_poll_context poll_ctx,
 				const char *caller)
 {
 	static atomic_t counter;
 	int comp_vector = 0;

 	if (dev->num_comp_vectors > 1)
 		comp_vector =
 			atomic_inc_return(&counter) %
 			min_t(int, dev->num_comp_vectors, num_online_cpus());

 	return __ib_alloc_cq(dev, private, nr_cqe, comp_vector, poll_ctx,
 			     caller);
 }
 EXPORT_SYMBOL(__ib_alloc_cq_any);

 /**
  * ib_free_cq - free a completion queue
  * @cq:		completion queue to free.
  */
 void ib_free_cq(struct ib_cq *cq)
 {
 	int ret;

 	if (WARN_ON_ONCE(atomic_read(&cq->usecnt)))
 		return;
 	if (WARN_ON_ONCE(cq->cqe_used))
 		return;

 	switch (cq->poll_ctx) {
 	case IB_POLL_DIRECT:
 		break;
 	case IB_POLL_SOFTIRQ:
 		irq_poll_disable(&cq->iop);
 		break;
 	case IB_POLL_WORKQUEUE:
 	case IB_POLL_UNBOUND_WORKQUEUE:
 		cancel_work_sync(&cq->work);
 		break;
 	default:
 		WARN_ON_ONCE(1);
 	}

 	rdma_dim_destroy(cq);
 	trace_cq_free(cq);
 	ret = cq->device->ops.destroy_cq(cq, NULL);
 	WARN_ONCE(ret, "Destroy of kernel CQ shouldn't fail");
 	rdma_restrack_del(&cq->res);
 	kfree(cq->wc);
 	kfree(cq);
 }
 EXPORT_SYMBOL(ib_free_cq);

 void ib_cq_pool_cleanup(struct ib_device *dev)
 {
 	struct ib_cq *cq, *n;
 	unsigned int i;

 	for (i = 0; i < ARRAY_SIZE(dev->cq_pools); i++) {
 		list_for_each_entry_safe(cq, n, &dev->cq_pools[i],
 					 pool_entry) {
 			WARN_ON(cq->cqe_used);
 			list_del(&cq->pool_entry);
 			cq->shared = false;
 			ib_free_cq(cq);
 		}
 	}
 }

 static int ib_alloc_cqs(struct ib_device *dev, unsigned int nr_cqes,
 			enum ib_poll_context poll_ctx)
 {
 	LIST_HEAD(tmp_list);
 	unsigned int nr_cqs, i;
 	struct ib_cq *cq, *n;
 	int ret;

 	if (poll_ctx > IB_POLL_LAST_POOL_TYPE) {
 		WARN_ON_ONCE(poll_ctx > IB_POLL_LAST_POOL_TYPE);
 		return -EINVAL;
 	}

 	/*
 	 * Allocate at least as many CQEs as requested, and otherwise
 	 * a reasonable batch size so that we can share CQs between
 	 * multiple users instead of allocating a larger number of CQs.
 	 */
 	nr_cqes = min_t(unsigned int, dev->attrs.max_cqe,
 			max(nr_cqes, IB_MAX_SHARED_CQ_SZ));
 	nr_cqs = min_t(unsigned int, dev->num_comp_vectors, num_online_cpus());
 	for (i = 0; i < nr_cqs; i++) {
 		cq = ib_alloc_cq(dev, NULL, nr_cqes, i, poll_ctx);
 		if (IS_ERR(cq)) {
 			ret = PTR_ERR(cq);
 			goto out_free_cqs;
 		}
 		cq->shared = true;
 		list_add_tail(&cq->pool_entry, &tmp_list);
 	}

 	spin_lock_irq(&dev->cq_pools_lock);
 	list_splice(&tmp_list, &dev->cq_pools[poll_ctx]);
 	spin_unlock_irq(&dev->cq_pools_lock);

 	return 0;

 out_free_cqs:
 	list_for_each_entry_safe(cq, n, &tmp_list, pool_entry) {
 		cq->shared = false;
 		ib_free_cq(cq);
 	}
 	return ret;
 }

 /**
  * ib_cq_pool_get() - Find the least used completion queue that matches
  *   a given cpu hint (or least used for wild card affinity) and fits
  *   nr_cqe.
  * @dev: rdma device
  * @nr_cqe: number of needed cqe entries
  * @comp_vector_hint: completion vector hint (-1) for the driver to assign
  *   a comp vector based on internal counter
  * @poll_ctx: cq polling context
  *
  * Finds a cq that satisfies @comp_vector_hint and @nr_cqe requirements and
  * claim entries in it for us.  In case there is no available cq, allocate
  * a new cq with the requirements and add it to the device pool.
  * IB_POLL_DIRECT cannot be used for shared cqs so it is not a valid value
  * for @poll_ctx.
  */
 struct ib_cq *ib_cq_pool_get(struct ib_device *dev, unsigned int nr_cqe,
 			     int comp_vector_hint,
 			     enum ib_poll_context poll_ctx)
 {
 	static unsigned int default_comp_vector;
 	unsigned int vector, num_comp_vectors;
 	struct ib_cq *cq, *found = NULL;
 	int ret;

 	if (poll_ctx > IB_POLL_LAST_POOL_TYPE) {
 		WARN_ON_ONCE(poll_ctx > IB_POLL_LAST_POOL_TYPE);
 		return ERR_PTR(-EINVAL);
 	}

 	num_comp_vectors =
 		min_t(unsigned int, dev->num_comp_vectors, num_online_cpus());
 	/* Project the affinty to the device completion vector range */
 	if (comp_vector_hint < 0) {
 		comp_vector_hint =
 			(READ_ONCE(default_comp_vector) + 1) % num_comp_vectors;
 		WRITE_ONCE(default_comp_vector, comp_vector_hint);
 	}
 	vector = comp_vector_hint % num_comp_vectors;

 	/*
 	 * Find the least used CQ with correct affinity and
 	 * enough free CQ entries
 	 */
 	while (!found) {
 		spin_lock_irq(&dev->cq_pools_lock);
 		list_for_each_entry(cq, &dev->cq_pools[poll_ctx],
 				    pool_entry) {
 			/*
 			 * Check to see if we have found a CQ with the
 			 * correct completion vector
 			 */
 			if (vector != cq->comp_vector)
 				continue;
 			if (cq->cqe_used + nr_cqe > cq->cqe)
 				continue;
 			found = cq;
 			break;
 		}

 		if (found) {
 			found->cqe_used += nr_cqe;
 			spin_unlock_irq(&dev->cq_pools_lock);

 			return found;
 		}
 		spin_unlock_irq(&dev->cq_pools_lock);

 		/*
 		 * Didn't find a match or ran out of CQs in the device
 		 * pool, allocate a new array of CQs.
 		 */
 		ret = ib_alloc_cqs(dev, nr_cqe, poll_ctx);
 		if (ret)
 			return ERR_PTR(ret);
 	}

 	return found;
 }
 EXPORT_SYMBOL(ib_cq_pool_get);

 /**
  * ib_cq_pool_put - Return a CQ taken from a shared pool.
  * @cq: The CQ to return.
  * @nr_cqe: The max number of cqes that the user had requested.
  */
 void ib_cq_pool_put(struct ib_cq *cq, unsigned int nr_cqe)
 {
 	if (WARN_ON_ONCE(nr_cqe > cq->cqe_used))
 		return;

 	spin_lock_irq(&cq->device->cq_pools_lock);
 	cq->cqe_used -= nr_cqe;
 	spin_unlock_irq(&cq->device->cq_pools_lock);
 }
 EXPORT_SYMBOL(ib_cq_pool_put);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2015 HGST, a Western Digital Company.
	*/
	#include <linux/err.h>
	#include <linux/slab.h>
	#include <rdma/ib_verbs.h>

	#include "core_priv.h"

	#include <trace/events/rdma_core.h>
	/* Max size for shared CQ, may require tuning */
	#define IB_MAX_SHARED_CQ_SZ 4096U

	/* # of WCs to poll for with a single call to ib_poll_cq */
	#define IB_POLL_BATCH 16
	#define IB_POLL_BATCH_DIRECT 8

	/* # of WCs to iterate over before yielding */
	#define IB_POLL_BUDGET_IRQ 256
	#define IB_POLL_BUDGET_WORKQUEUE 65536

	#define IB_POLL_FLAGS \
	(IB_CQ_NEXT_COMP \| IB_CQ_REPORT_MISSED_EVENTS)

	static const struct dim_cq_moder
	rdma_dim_prof[RDMA_DIM_PARAMS_NUM_PROFILES] = {
	{1, 0, 1, 0},
	{1, 0, 4, 0},
	{2, 0, 4, 0},
	{2, 0, 8, 0},
	{4, 0, 8, 0},
	{16, 0, 8, 0},
	{16, 0, 16, 0},
	{32, 0, 16, 0},
	{32, 0, 32, 0},
	};

	static void ib_cq_rdma_dim_work(struct work_struct *w)
	{
	struct dim *dim = container_of(w, struct dim, work);
	struct ib_cq *cq = dim->priv;

	u16 usec = rdma_dim_prof[dim->profile_ix].usec;
	u16 comps = rdma_dim_prof[dim->profile_ix].comps;

	dim->state = DIM_START_MEASURE;

	trace_cq_modify(cq, comps, usec);
	cq->device->ops.modify_cq(cq, comps, usec);
	}

	static void rdma_dim_init(struct ib_cq *cq)
	{
	struct dim *dim;

	if (!cq->device->ops.modify_cq \|\| !cq->device->use_cq_dim \|\|
	cq->poll_ctx == IB_POLL_DIRECT)
	return;

	dim = kzalloc(sizeof(struct dim), GFP_KERNEL);
	if (!dim)
	return;

	dim->state = DIM_START_MEASURE;
	dim->tune_state = DIM_GOING_RIGHT;
	dim->profile_ix = RDMA_DIM_START_PROFILE;
	dim->priv = cq;
	cq->dim = dim;

	INIT_WORK(&dim->work, ib_cq_rdma_dim_work);
	}

	static void rdma_dim_destroy(struct ib_cq *cq)
	{
	if (!cq->dim)
	return;

	cancel_work_sync(&cq->dim->work);
	kfree(cq->dim);
	}

	static int __poll_cq(struct ib_cq cq, int num_entries, struct ib_wc wc)
	{
	int rc;

	rc = ib_poll_cq(cq, num_entries, wc);
	trace_cq_poll(cq, num_entries, rc);
	return rc;
	}

	static int __ib_process_cq(struct ib_cq cq, int budget, struct ib_wc wcs,
	int batch)
	{
	int i, n, completed = 0;

	trace_cq_process(cq);

	/*
	* budget might be (-1) if the caller does not
	* want to bound this call, thus we need unsigned
	* minimum here.
	*/
	while ((n = __poll_cq(cq, min_t(u32, batch,
	budget - completed), wcs)) > 0) {
	for (i = 0; i < n; i++) {
	struct ib_wc *wc = &wcs[i];

	if (wc->wr_cqe)
	wc->wr_cqe->done(cq, wc);
	else
	WARN_ON_ONCE(wc->status == IB_WC_SUCCESS);
	}

	completed += n;

	if (n != batch \|\| (budget != -1 && completed >= budget))
	break;
	}

	return completed;
	}

	/**
	* ib_process_cq_direct - process a CQ in caller context
	* @cq: CQ to process
	* @budget: number of CQEs to poll for
	*
	* This function is used to process all outstanding CQ entries.
	* It does not offload CQ processing to a different context and does
	* not ask for completion interrupts from the HCA.
	* Using direct processing on CQ with non IB_POLL_DIRECT type may trigger
	* concurrent processing.
	*
	* Note: do not pass -1 as %budget unless it is guaranteed that the number
	* of completions that will be processed is small.
	*/
	int ib_process_cq_direct(struct ib_cq *cq, int budget)
	{
	struct ib_wc wcs[IB_POLL_BATCH_DIRECT];

	return __ib_process_cq(cq, budget, wcs, IB_POLL_BATCH_DIRECT);
	}
	EXPORT_SYMBOL(ib_process_cq_direct);

	static void ib_cq_completion_direct(struct ib_cq cq, void private)
	{
	WARN_ONCE(1, "got unsolicited completion for CQ 0x%p\n", cq);
	}

	static int ib_poll_handler(struct irq_poll *iop, int budget)
	{
	struct ib_cq *cq = container_of(iop, struct ib_cq, iop);
	struct dim *dim = cq->dim;
	int completed;

	completed = __ib_process_cq(cq, budget, cq->wc, IB_POLL_BATCH);
	if (completed < budget) {
	irq_poll_complete(&cq->iop);
	if (ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0) {
	trace_cq_reschedule(cq);
	irq_poll_sched(&cq->iop);
	}
	}

	if (dim)
	rdma_dim(dim, completed);

	return completed;
	}

	static void ib_cq_completion_softirq(struct ib_cq cq, void private)
	{
	trace_cq_schedule(cq);
	irq_poll_sched(&cq->iop);
	}

	static void ib_cq_poll_work(struct work_struct *work)
	{
	struct ib_cq *cq = container_of(work, struct ib_cq, work);
	int completed;

	completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE, cq->wc,
	IB_POLL_BATCH);
	if (completed >= IB_POLL_BUDGET_WORKQUEUE \|\|
	ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0)
	queue_work(cq->comp_wq, &cq->work);
	else if (cq->dim)
	rdma_dim(cq->dim, completed);
	}

	static void ib_cq_completion_workqueue(struct ib_cq cq, void private)
	{
	trace_cq_schedule(cq);
	queue_work(cq->comp_wq, &cq->work);
	}

	/**
	* __ib_alloc_cq - allocate a completion queue
	* @dev: device to allocate the CQ for
	* @private: driver private data, accessible from cq->cq_context
	* @nr_cqe: number of CQEs to allocate
	* @comp_vector: HCA completion vectors for this CQ
	* @poll_ctx: context to poll the CQ from.
	* @caller: module owner name.
	*
	* This is the proper interface to allocate a CQ for in-kernel users. A
	* CQ allocated with this interface will automatically be polled from the
	* specified context. The ULP must use wr->wr_cqe instead of wr->wr_id
	* to use this CQ abstraction.
	*/
	struct ib_cq __ib_alloc_cq(struct ib_device dev, void *private, int nr_cqe,
	int comp_vector, enum ib_poll_context poll_ctx,
	const char *caller)
	{
	struct ib_cq_init_attr cq_attr = {
	.cqe = nr_cqe,
	.comp_vector = comp_vector,
	};
	struct ib_cq *cq;
	int ret = -ENOMEM;

	cq = rdma_zalloc_drv_obj(dev, ib_cq);
	if (!cq)
	return ERR_PTR(ret);

	cq->device = dev;
	cq->cq_context = private;
	cq->poll_ctx = poll_ctx;
	atomic_set(&cq->usecnt, 0);
	cq->comp_vector = comp_vector;

	cq->wc = kmalloc_array(IB_POLL_BATCH, sizeof(*cq->wc), GFP_KERNEL);
	if (!cq->wc)
	goto out_free_cq;

	rdma_restrack_new(&cq->res, RDMA_RESTRACK_CQ);
	rdma_restrack_set_name(&cq->res, caller);

	ret = dev->ops.create_cq(cq, &cq_attr, NULL);
	if (ret)
	goto out_free_wc;

	rdma_dim_init(cq);

	switch (cq->poll_ctx) {
	case IB_POLL_DIRECT:
	cq->comp_handler = ib_cq_completion_direct;
	break;
	case IB_POLL_SOFTIRQ:
	cq->comp_handler = ib_cq_completion_softirq;

	irq_poll_init(&cq->iop, IB_POLL_BUDGET_IRQ, ib_poll_handler);
	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
	break;
	case IB_POLL_WORKQUEUE:
	case IB_POLL_UNBOUND_WORKQUEUE:
	cq->comp_handler = ib_cq_completion_workqueue;
	INIT_WORK(&cq->work, ib_cq_poll_work);
	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
	cq->comp_wq = (cq->poll_ctx == IB_POLL_WORKQUEUE) ?
	ib_comp_wq : ib_comp_unbound_wq;
	break;
	default:
	ret = -EINVAL;
	goto out_destroy_cq;
	}

	rdma_restrack_add(&cq->res);
	trace_cq_alloc(cq, nr_cqe, comp_vector, poll_ctx);
	return cq;

	out_destroy_cq:
	rdma_dim_destroy(cq);
	cq->device->ops.destroy_cq(cq, NULL);
	out_free_wc:
	rdma_restrack_put(&cq->res);
	kfree(cq->wc);
	out_free_cq:
	kfree(cq);
	trace_cq_alloc_error(nr_cqe, comp_vector, poll_ctx, ret);
	return ERR_PTR(ret);
	}
	EXPORT_SYMBOL(__ib_alloc_cq);

	/**
	* __ib_alloc_cq_any - allocate a completion queue
	* @dev: device to allocate the CQ for
	* @private: driver private data, accessible from cq->cq_context
	* @nr_cqe: number of CQEs to allocate
	* @poll_ctx: context to poll the CQ from
	* @caller: module owner name
	*
	* Attempt to spread ULP Completion Queues over each device's interrupt
	* vectors. A simple best-effort mechanism is used.
	*/
	struct ib_cq __ib_alloc_cq_any(struct ib_device dev, void *private,
	int nr_cqe, enum ib_poll_context poll_ctx,
	const char *caller)
	{
	static atomic_t counter;
	int comp_vector = 0;

	if (dev->num_comp_vectors > 1)
	comp_vector =
	atomic_inc_return(&counter) %
	min_t(int, dev->num_comp_vectors, num_online_cpus());

	return __ib_alloc_cq(dev, private, nr_cqe, comp_vector, poll_ctx,
	caller);
	}
	EXPORT_SYMBOL(__ib_alloc_cq_any);

	/**
	* ib_free_cq - free a completion queue
	* @cq: completion queue to free.
	*/
	void ib_free_cq(struct ib_cq *cq)
	{
	int ret;

	if (WARN_ON_ONCE(atomic_read(&cq->usecnt)))
	return;
	if (WARN_ON_ONCE(cq->cqe_used))
	return;

	switch (cq->poll_ctx) {
	case IB_POLL_DIRECT:
	break;
	case IB_POLL_SOFTIRQ:
	irq_poll_disable(&cq->iop);
	break;
	case IB_POLL_WORKQUEUE:
	case IB_POLL_UNBOUND_WORKQUEUE:
	cancel_work_sync(&cq->work);
	break;
	default:
	WARN_ON_ONCE(1);
	}

	rdma_dim_destroy(cq);
	trace_cq_free(cq);
	ret = cq->device->ops.destroy_cq(cq, NULL);
	WARN_ONCE(ret, "Destroy of kernel CQ shouldn't fail");
	rdma_restrack_del(&cq->res);
	kfree(cq->wc);
	kfree(cq);
	}
	EXPORT_SYMBOL(ib_free_cq);

	void ib_cq_pool_cleanup(struct ib_device *dev)
	{
	struct ib_cq cq, n;
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(dev->cq_pools); i++) {
	list_for_each_entry_safe(cq, n, &dev->cq_pools[i],
	pool_entry) {
	WARN_ON(cq->cqe_used);
	list_del(&cq->pool_entry);
	cq->shared = false;
	ib_free_cq(cq);
	}
	}
	}

	static int ib_alloc_cqs(struct ib_device *dev, unsigned int nr_cqes,
	enum ib_poll_context poll_ctx)
	{
	LIST_HEAD(tmp_list);
	unsigned int nr_cqs, i;
	struct ib_cq cq, n;
	int ret;

	if (poll_ctx > IB_POLL_LAST_POOL_TYPE) {
	WARN_ON_ONCE(poll_ctx > IB_POLL_LAST_POOL_TYPE);
	return -EINVAL;
	}

	/*
	* Allocate at least as many CQEs as requested, and otherwise
	* a reasonable batch size so that we can share CQs between
	* multiple users instead of allocating a larger number of CQs.
	*/
	nr_cqes = min_t(unsigned int, dev->attrs.max_cqe,
	max(nr_cqes, IB_MAX_SHARED_CQ_SZ));
	nr_cqs = min_t(unsigned int, dev->num_comp_vectors, num_online_cpus());
	for (i = 0; i < nr_cqs; i++) {
	cq = ib_alloc_cq(dev, NULL, nr_cqes, i, poll_ctx);
	if (IS_ERR(cq)) {
	ret = PTR_ERR(cq);
	goto out_free_cqs;
	}
	cq->shared = true;
	list_add_tail(&cq->pool_entry, &tmp_list);
	}

	spin_lock_irq(&dev->cq_pools_lock);
	list_splice(&tmp_list, &dev->cq_pools[poll_ctx]);
	spin_unlock_irq(&dev->cq_pools_lock);

	return 0;

	out_free_cqs:
	list_for_each_entry_safe(cq, n, &tmp_list, pool_entry) {
	cq->shared = false;
	ib_free_cq(cq);
	}
	return ret;
	}

	/**
	* ib_cq_pool_get() - Find the least used completion queue that matches
	* a given cpu hint (or least used for wild card affinity) and fits
	* nr_cqe.
	* @dev: rdma device
	* @nr_cqe: number of needed cqe entries
	* @comp_vector_hint: completion vector hint (-1) for the driver to assign
	* a comp vector based on internal counter
	* @poll_ctx: cq polling context
	*
	* Finds a cq that satisfies @comp_vector_hint and @nr_cqe requirements and
	* claim entries in it for us. In case there is no available cq, allocate
	* a new cq with the requirements and add it to the device pool.
	* IB_POLL_DIRECT cannot be used for shared cqs so it is not a valid value
	* for @poll_ctx.
	*/
	struct ib_cq ib_cq_pool_get(struct ib_device dev, unsigned int nr_cqe,
	int comp_vector_hint,
	enum ib_poll_context poll_ctx)
	{
	static unsigned int default_comp_vector;
	unsigned int vector, num_comp_vectors;
	struct ib_cq cq, found = NULL;
	int ret;

	if (poll_ctx > IB_POLL_LAST_POOL_TYPE) {
	WARN_ON_ONCE(poll_ctx > IB_POLL_LAST_POOL_TYPE);
	return ERR_PTR(-EINVAL);
	}

	num_comp_vectors =
	min_t(unsigned int, dev->num_comp_vectors, num_online_cpus());
	/* Project the affinty to the device completion vector range */
	if (comp_vector_hint < 0) {
	comp_vector_hint =
	(READ_ONCE(default_comp_vector) + 1) % num_comp_vectors;
	WRITE_ONCE(default_comp_vector, comp_vector_hint);
	}
	vector = comp_vector_hint % num_comp_vectors;

	/*
	* Find the least used CQ with correct affinity and
	* enough free CQ entries
	*/
	while (!found) {
	spin_lock_irq(&dev->cq_pools_lock);
	list_for_each_entry(cq, &dev->cq_pools[poll_ctx],
	pool_entry) {
	/*
	* Check to see if we have found a CQ with the
	* correct completion vector
	*/
	if (vector != cq->comp_vector)
	continue;
	if (cq->cqe_used + nr_cqe > cq->cqe)
	continue;
	found = cq;
	break;
	}

	if (found) {
	found->cqe_used += nr_cqe;
	spin_unlock_irq(&dev->cq_pools_lock);

	return found;
	}
	spin_unlock_irq(&dev->cq_pools_lock);

	/*
	* Didn't find a match or ran out of CQs in the device
	* pool, allocate a new array of CQs.
	*/
	ret = ib_alloc_cqs(dev, nr_cqe, poll_ctx);
	if (ret)
	return ERR_PTR(ret);
	}

	return found;
	}
	EXPORT_SYMBOL(ib_cq_pool_get);

	/**
	* ib_cq_pool_put - Return a CQ taken from a shared pool.
	* @cq: The CQ to return.
	* @nr_cqe: The max number of cqes that the user had requested.
	*/
	void ib_cq_pool_put(struct ib_cq *cq, unsigned int nr_cqe)
	{
	if (WARN_ON_ONCE(nr_cqe > cq->cqe_used))
	return;

	spin_lock_irq(&cq->device->cq_pools_lock);
	cq->cqe_used -= nr_cqe;
	spin_unlock_irq(&cq->device->cq_pools_lock);
	}
	EXPORT_SYMBOL(ib_cq_pool_put);