[PATCH v3 08/15] IB/pvrdma: Add support for Completion Queues

[Adit Ranadive <aditr-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>]

This patch adds the support for creating and destroying completion queues
on the paravirtual RDMA device.

Changes v2->v3:
 - Removed boolean from pvrdma_cmd_post.
 - Return -EAGAIN if qp retrieved from CQE is bogus.
 - Check for invalid index of ring.

Reviewed-by: Jorgen Hansen <jhansen-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
Reviewed-by: George Zhang <georgezhang-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
Reviewed-by: Aditya Sarwade <asarwade-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
Reviewed-by: Bryan Tan <bryantan-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Adit Ranadive <aditr-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
---
 drivers/infiniband/hw/pvrdma/pvrdma_cq.c | 437 +++++++++++++++++++++++++++++++
 1 file changed, 437 insertions(+)
 create mode 100644 drivers/infiniband/hw/pvrdma/pvrdma_cq.c

diff --git a/drivers/infiniband/hw/pvrdma/pvrdma_cq.c b/drivers/infiniband/hw/pvrdma/pvrdma_cq.c
new file mode 100644
index 0000000..f7f92fe
--- /dev/null
+++ b/drivers/infiniband/hw/pvrdma/pvrdma_cq.c
@@ -0,0 +1,437 @@
+/*
+ * Copyright (c) 2012-2016 VMware, Inc.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of EITHER the GNU General Public License
+ * version 2 as published by the Free Software Foundation or the BSD
+ * 2-Clause License. This program is distributed in the hope that 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 version 2 for more details at
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program available in the file COPYING in the main
+ * directory of this source tree.
+ *
+ * The BSD 2-Clause License
+ *
+ *     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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <asm/page.h>
+#include <linux/io.h>
+#include <linux/wait.h>
+#include <rdma/ib_addr.h>
+#include <rdma/ib_smi.h>
+#include <rdma/ib_user_verbs.h>
+
+#include "pvrdma.h"
+#include "pvrdma_user.h"
+
+/**
+ * pvrdma_req_notify_cq - request notification for a completion queue
+ * @ibcq: the completion queue
+ * @notify_flags: notification flags
+ *
+ * @return: 0 for success.
+ */
+int pvrdma_req_notify_cq(struct ib_cq *ibcq,
+			 enum ib_cq_notify_flags notify_flags)
+{
+	struct pvrdma_dev *dev = to_vdev(ibcq->device);
+	struct pvrdma_cq *cq = to_vcq(ibcq);
+	u32 val = cq->cq_handle;
+
+	val |= (notify_flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
+		PVRDMA_UAR_CQ_ARM_SOL : PVRDMA_UAR_CQ_ARM;
+
+	writel(cpu_to_le32(val), dev->driver_uar.map + PVRDMA_UAR_CQ_OFFSET);
+
+	return 0;
+}
+
+/**
+ * pvrdma_create_cq - create completion queue
+ * @ibdev: the device
+ * @attr: completion queue attributes
+ * @context: user context
+ * @udata: user data
+ *
+ * @return: ib_cq completion queue pointer on success,
+ *          otherwise returns negative errno.
+ */
+struct ib_cq *pvrdma_create_cq(struct ib_device *ibdev,
+			       const struct ib_cq_init_attr *attr,
+			       struct ib_ucontext *context,
+			       struct ib_udata *udata)
+{
+	int entries = attr->cqe;
+	struct pvrdma_dev *dev = to_vdev(ibdev);
+	struct pvrdma_cq *cq;
+	int ret;
+	int npages;
+	unsigned long flags;
+	union pvrdma_cmd_req req;
+	union pvrdma_cmd_resp rsp;
+	struct pvrdma_cmd_create_cq *cmd = &req.create_cq;
+	struct pvrdma_cmd_create_cq_resp *resp = &rsp.create_cq_resp;
+	struct pvrdma_create_cq ucmd;
+
+	BUILD_BUG_ON(sizeof(struct pvrdma_cqe) != 64);
+
+	entries = roundup_pow_of_two(entries);
+	if (entries < 1 || entries > dev->dsr->caps.max_cqe)
+		return ERR_PTR(-EINVAL);
+
+	if (!atomic_add_unless(&dev->num_cqs, 1, dev->dsr->caps.max_cq))
+		return ERR_PTR(-EINVAL);
+
+	cq = kzalloc(sizeof(*cq), GFP_KERNEL);
+	if (!cq) {
+		atomic_dec(&dev->num_cqs);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	cq->ibcq.cqe = entries;
+
+	if (context) {
+		if (ib_copy_from_udata(&ucmd, udata, sizeof(ucmd))) {
+			ret = -EFAULT;
+			goto err_cq;
+		}
+
+		cq->umem = ib_umem_get(context, ucmd.buf_addr, ucmd.buf_size,
+				       IB_ACCESS_LOCAL_WRITE, 1);
+		if (IS_ERR(cq->umem)) {
+			ret = PTR_ERR(cq->umem);
+			goto err_cq;
+		}
+
+		npages = ib_umem_page_count(cq->umem);
+	} else {
+		cq->is_kernel = true;
+
+		/* One extra page for shared ring state */
+		npages = 1 + (entries * sizeof(struct pvrdma_cqe) +
+			      PAGE_SIZE - 1) / PAGE_SIZE;
+
+		/* Skip header page. */
+		cq->offset = PAGE_SIZE;
+	}
+
+	if (npages < 0 || npages > PVRDMA_PAGE_DIR_MAX_PAGES) {
+		dev_warn(&dev->pdev->dev,
+			 "overflow pages in completion queue\n");
+		ret = -EINVAL;
+		goto err_umem;
+	}
+
+	ret = pvrdma_page_dir_init(dev, &cq->pdir, npages, cq->is_kernel);
+	if (ret) {
+		dev_warn(&dev->pdev->dev,
+			 "could not allocate page directory\n");
+		goto err_umem;
+	}
+
+	if (cq->is_kernel) {
+		/* Ring state is always the first page. */
+		cq->ring_state = cq->pdir.pages[0];
+	} else {
+		pvrdma_page_dir_insert_umem(&cq->pdir, cq->umem, 0);
+	}
+
+	atomic_set(&cq->refcnt, 1);
+	init_waitqueue_head(&cq->wait);
+	spin_lock_init(&cq->cq_lock);
+
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->hdr.cmd = PVRDMA_CMD_CREATE_CQ;
+	cmd->nchunks = npages;
+	cmd->ctx_handle = (context) ?
+		(u64)to_vucontext(context)->ctx_handle : 0;
+	cmd->cqe = entries;
+	cmd->pdir_dma = cq->pdir.dir_dma;
+	ret = pvrdma_cmd_post(dev, &req, &rsp);
+
+	if (ret < 0 || rsp.hdr.ack != PVRDMA_CMD_CREATE_CQ_RESP) {
+		dev_warn(&dev->pdev->dev,
+			 "could not create completion queue\n");
+		goto err_page_dir;
+	}
+
+	cq->ibcq.cqe = resp->cqe;
+	cq->cq_handle = resp->cq_handle;
+	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
+	dev->cq_tbl[cq->cq_handle % dev->dsr->caps.max_cq] = cq;
+	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);
+
+	if (context) {
+		cq->uar = &(to_vucontext(context)->uar);
+
+		/* Copy udata back. */
+		if (ib_copy_to_udata(udata, &cq->cq_handle, sizeof(__u32))) {
+			dev_warn(&dev->pdev->dev,
+				 "failed to copy back udata\n");
+			ret = -EINVAL;
+			goto err_page_dir;
+		}
+	}
+
+	return &cq->ibcq;
+
+err_page_dir:
+	pvrdma_page_dir_cleanup(dev, &cq->pdir);
+err_umem:
+	if (context)
+		ib_umem_release(cq->umem);
+err_cq:
+	atomic_dec(&dev->num_cqs);
+	kfree(cq);
+
+	return ERR_PTR(ret);
+}
+
+static void pvrdma_free_cq(struct pvrdma_dev *dev, struct pvrdma_cq *cq)
+{
+	atomic_dec(&cq->refcnt);
+	wait_event(cq->wait, !atomic_read(&cq->refcnt));
+
+	if (!cq->is_kernel)
+		ib_umem_release(cq->umem);
+
+	pvrdma_page_dir_cleanup(dev, &cq->pdir);
+	kfree(cq);
+}
+
+/**
+ * pvrdma_destroy_cq - destroy completion queue
+ * @cq: the completion queue to destroy.
+ *
+ * @return: 0 for success.
+ */
+int pvrdma_destroy_cq(struct ib_cq *cq)
+{
+	struct pvrdma_cq *vcq = to_vcq(cq);
+	union pvrdma_cmd_req req;
+	struct pvrdma_cmd_destroy_cq *cmd = &req.destroy_cq;
+	struct pvrdma_dev *dev = to_vdev(cq->device);
+	unsigned long flags;
+	int ret;
+
+	memset(cmd, 0, sizeof(*cmd));
+	cmd->hdr.cmd = PVRDMA_CMD_DESTROY_CQ;
+	cmd->cq_handle = vcq->cq_handle;
+
+	ret = pvrdma_cmd_post(dev, &req, NULL);
+	if (ret < 0)
+		dev_warn(&dev->pdev->dev,
+			 "could not destroy completion queue\n");
+
+	/* free cq's resources */
+	spin_lock_irqsave(&dev->cq_tbl_lock, flags);
+	dev->cq_tbl[vcq->cq_handle] = NULL;
+	spin_unlock_irqrestore(&dev->cq_tbl_lock, flags);
+
+	pvrdma_free_cq(dev, vcq);
+	atomic_dec(&dev->num_cqs);
+
+	return ret;
+}
+
+/**
+ * pvrdma_modify_cq - modify the CQ moderation parameters
+ * @ibcq: the CQ to modify
+ * @cq_count: number of CQEs that will trigger an event
+ * @cq_period: max period of time in usec before triggering an event
+ *
+ * @return: -EOPNOTSUPP as CQ resize is not supported.
+ */
+int pvrdma_modify_cq(struct ib_cq *cq, u16 cq_count, u16 cq_period)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline struct pvrdma_cqe *get_cqe(struct pvrdma_cq *cq, int i)
+{
+	return (struct pvrdma_cqe *)pvrdma_page_dir_get_ptr(
+					&cq->pdir,
+					cq->offset +
+					sizeof(struct pvrdma_cqe) * i);
+}
+
+void pvrdma_flush_cqe(struct pvrdma_qp *qp, struct pvrdma_cq *cq)
+{
+	int head;
+	int has_data;
+
+	if (!cq->is_kernel)
+		return;
+
+	/* Lock held */
+	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
+					    cq->ibcq.cqe, &head);
+	if (unlikely(has_data > 0)) {
+		int items;
+		int curr;
+		int tail = pvrdma_idx(&cq->ring_state->rx.prod_tail,
+				      cq->ibcq.cqe);
+		struct pvrdma_cqe *cqe;
+		struct pvrdma_cqe *curr_cqe;
+
+		items = (tail > head) ? (tail - head) :
+			(cq->ibcq.cqe - head + tail);
+		curr = --tail;
+		while (items-- > 0) {
+			if (curr < 0)
+				curr = cq->ibcq.cqe - 1;
+			if (tail < 0)
+				tail = cq->ibcq.cqe - 1;
+			curr_cqe = get_cqe(cq, curr);
+			if ((curr_cqe->qp & 0xFFFF) != qp->qp_handle) {
+				if (curr != tail) {
+					cqe = get_cqe(cq, tail);
+					*cqe = *curr_cqe;
+				}
+				tail--;
+			} else {
+				pvrdma_idx_ring_inc(
+					&cq->ring_state->rx.cons_head,
+					cq->ibcq.cqe);
+			}
+			curr--;
+		}
+	}
+}
+
+static int pvrdma_poll_one(struct pvrdma_cq *cq, struct pvrdma_qp **cur_qp,
+			   struct ib_wc *wc)
+{
+	struct pvrdma_dev *dev = to_vdev(cq->ibcq.device);
+	int has_data;
+	unsigned int head;
+	bool tried = false;
+	struct pvrdma_cqe *cqe;
+
+retry:
+	has_data = pvrdma_idx_ring_has_data(&cq->ring_state->rx,
+					    cq->ibcq.cqe, &head);
+	if (has_data == 0) {
+		u32 val;
+
+		if (tried)
+			return -EAGAIN;
+
+		/* Pass down POLL to give physical HCA a chance to poll. */
+		val = cq->cq_handle | PVRDMA_UAR_CQ_POLL;
+		writel(cpu_to_le32(val),
+		       dev->driver_uar.map + PVRDMA_UAR_CQ_OFFSET);
+
+		tried = true;
+		goto retry;
+	} else if (has_data == PVRDMA_INVALID_IDX) {
+		/* Ring state could be corrupted. Treat as unrecoverable. */
+		return -EINVAL;
+	}
+
+	cqe = get_cqe(cq, head);
+
+	/* Ensure cqe is valid. */
+	rmb();
+	if (dev->qp_tbl[cqe->qp & 0xffff])
+		*cur_qp = (struct pvrdma_qp *)dev->qp_tbl[cqe->qp & 0xffff];
+	else
+		return -EAGAIN;
+
+	wc->opcode = pvrdma_wc_opcode_to_ib(cqe->opcode);
+	wc->status = pvrdma_wc_status_to_ib(cqe->status);
+	wc->wr_id = cqe->wr_id;
+	wc->qp = &(*cur_qp)->ibqp;
+	wc->byte_len = cqe->byte_len;
+	wc->ex.imm_data = cqe->imm_data;
+	wc->src_qp = cqe->src_qp;
+	wc->wc_flags = pvrdma_wc_flags_to_ib(cqe->wc_flags);
+	wc->pkey_index = cqe->pkey_index;
+	wc->slid = cqe->slid;
+	wc->sl = cqe->sl;
+	wc->dlid_path_bits = cqe->dlid_path_bits;
+	wc->port_num = cqe->port_num;
+	wc->vendor_err = 0;
+
+	/* Update shared ring state */
+	pvrdma_idx_ring_inc(&cq->ring_state->rx.cons_head, cq->ibcq.cqe);
+
+	return 0;
+}
+
+/**
+ * pvrdma_poll_cq - poll for work completion queue entries
+ * @ibcq: completion queue
+ * @num_entries: the maximum number of entries
+ * @entry: pointer to work completion array
+ *
+ * @return: number of polled completion entries
+ */
+int pvrdma_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
+{
+	struct pvrdma_cq *cq = to_vcq(ibcq);
+	struct pvrdma_qp *cur_qp = NULL;
+	unsigned long flags;
+	int npolled;
+	int ret;
+
+	if (num_entries < 1)
+		return -EINVAL;
+
+	spin_lock_irqsave(&cq->cq_lock, flags);
+	for (npolled = 0; npolled < num_entries; ++npolled) {
+		ret = pvrdma_poll_one(cq, &cur_qp, wc + npolled);
+		if (ret)
+			break;
+	}
+
+	spin_unlock_irqrestore(&cq->cq_lock, flags);
+
+	if ((ret == 0) || (ret == -EAGAIN))
+		return npolled;
+	else
+		return ret;
+}
+
+/**
+ * pvrdma_resize_cq - resize CQ
+ * @ibcq: the completion queue
+ * @entries: CQ entries
+ * @udata: user data
+ *
+ * @return: -EOPNOTSUPP as CQ resize is not supported.
+ */
+int pvrdma_resize_cq(struct ib_cq *ibcq, int entries, struct ib_udata *udata)
+{
+	return -EOPNOTSUPP;
+}
+
-- 
2.7.4

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