drivers/staging/rdma/hfi1/mmap.c

/*
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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 for more details.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2015 Intel Corporation.
 *
 * 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.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 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
 * OWNER 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 <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <asm/pgtable.h>

#include "verbs.h"

/**
 * hfi1_release_mmap_info - free mmap info structure
 * @ref: a pointer to the kref within struct hfi1_mmap_info
 */
void hfi1_release_mmap_info(struct kref *ref)
{
	struct hfi1_mmap_info *ip =
		container_of(ref, struct hfi1_mmap_info, ref);
	struct hfi1_ibdev *dev = to_idev(ip->context->device);

	spin_lock_irq(&dev->pending_lock);
	list_del(&ip->pending_mmaps);
	spin_unlock_irq(&dev->pending_lock);

	vfree(ip->obj);
	kfree(ip);
}

/*
 * open and close keep track of how many times the CQ is mapped,
 * to avoid releasing it.
 */
static void hfi1_vma_open(struct vm_area_struct *vma)
{
	struct hfi1_mmap_info *ip = vma->vm_private_data;

	kref_get(&ip->ref);
}

static void hfi1_vma_close(struct vm_area_struct *vma)
{
	struct hfi1_mmap_info *ip = vma->vm_private_data;

	kref_put(&ip->ref, hfi1_release_mmap_info);
}

static struct vm_operations_struct hfi1_vm_ops = {
	.open =     hfi1_vma_open,
	.close =    hfi1_vma_close,
};

/**
 * hfi1_mmap - create a new mmap region
 * @context: the IB user context of the process making the mmap() call
 * @vma: the VMA to be initialized
 * Return zero if the mmap is OK. Otherwise, return an errno.
 */
int hfi1_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
{
	struct hfi1_ibdev *dev = to_idev(context->device);
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
	unsigned long size = vma->vm_end - vma->vm_start;
	struct hfi1_mmap_info *ip, *pp;
	int ret = -EINVAL;

	/*
	 * Search the device's list of objects waiting for a mmap call.
	 * Normally, this list is very short since a call to create a
	 * CQ, QP, or SRQ is soon followed by a call to mmap().
	 */
	spin_lock_irq(&dev->pending_lock);
	list_for_each_entry_safe(ip, pp, &dev->pending_mmaps,
				 pending_mmaps) {
		/* Only the creator is allowed to mmap the object */
		if (context != ip->context || (__u64) offset != ip->offset)
			continue;
		/* Don't allow a mmap larger than the object. */
		if (size > ip->size)
			break;

		list_del_init(&ip->pending_mmaps);
		spin_unlock_irq(&dev->pending_lock);

		ret = remap_vmalloc_range(vma, ip->obj, 0);
		if (ret)
			goto done;
		vma->vm_ops = &hfi1_vm_ops;
		vma->vm_private_data = ip;
		hfi1_vma_open(vma);
		goto done;
	}
	spin_unlock_irq(&dev->pending_lock);
done:
	return ret;
}

/*
 * Allocate information for hfi1_mmap
 */
struct hfi1_mmap_info *hfi1_create_mmap_info(struct hfi1_ibdev *dev,
					     u32 size,
					     struct ib_ucontext *context,
					     void *obj) {
	struct hfi1_mmap_info *ip;

	ip = kmalloc(sizeof(*ip), GFP_KERNEL);
	if (!ip)
		goto bail;

	size = PAGE_ALIGN(size);

	spin_lock_irq(&dev->mmap_offset_lock);
	if (dev->mmap_offset == 0)
		dev->mmap_offset = PAGE_SIZE;
	ip->offset = dev->mmap_offset;
	dev->mmap_offset += size;
	spin_unlock_irq(&dev->mmap_offset_lock);

	INIT_LIST_HEAD(&ip->pending_mmaps);
	ip->size = size;
	ip->context = context;
	ip->obj = obj;
	kref_init(&ip->ref);

bail:
	return ip;
}

void hfi1_update_mmap_info(struct hfi1_ibdev *dev, struct hfi1_mmap_info *ip,
			   u32 size, void *obj)
{
	size = PAGE_ALIGN(size);

	spin_lock_irq(&dev->mmap_offset_lock);
	if (dev->mmap_offset == 0)
		dev->mmap_offset = PAGE_SIZE;
	ip->offset = dev->mmap_offset;
	dev->mmap_offset += size;
	spin_unlock_irq(&dev->mmap_offset_lock);

	ip->size = size;
	ip->obj = obj;
}