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/*
* Copyright (c) 2013-2015, Mellanox Technologies. 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/kref.h>
#include <linux/slab.h>
#include <linux/sched/mm.h>
#include <rdma/ib_umem.h>
#include "mlx5_ib.h"
#define MLX5_IB_DBR_SIZE (sizeof(__be32) * 2)
struct mlx5_ib_user_db_page {
struct list_head list;
struct ib_umem *umem;
struct ib_uverbs_buffer_desc desc;
int refcnt;
struct mm_struct *mm;
};
static int mlx5_ib_db_map_user_desc(struct mlx5_ib_ucontext *context,
const struct ib_uverbs_buffer_desc *desc,
struct mlx5_db *db)
{
struct mlx5_ib_user_db_page *page;
struct ib_umem *umem;
int err = 0;
if (desc->length < MLX5_IB_DBR_SIZE)
return -EINVAL;
/*
* For VA descriptors the umem is normalized to a single PAGE_SIZE
* region, so reject offsets that would place the 8-byte DBR
* straddling the page boundary.
*/
if (desc->type == IB_UVERBS_BUFFER_TYPE_VA &&
(desc->addr & ~PAGE_MASK) > PAGE_SIZE - MLX5_IB_DBR_SIZE)
return -EINVAL;
mutex_lock(&context->db_page_mutex);
/*
* Only VA-typed descriptors are eligible to share a per-page
* doorbell umem; FD-typed descriptors are pinned individually.
*/
if (desc->type == IB_UVERBS_BUFFER_TYPE_VA) {
list_for_each_entry(page, &context->db_page_list, list) {
if (current->mm != page->mm)
continue;
if (page->desc.addr == (desc->addr & PAGE_MASK))
goto found;
}
}
page = kzalloc_obj(*page);
if (!page) {
err = -ENOMEM;
goto out;
}
page->desc = *desc;
/*
* Normalize VA descriptors to a page-aligned PAGE_SIZE region so
* multiple DBRs that fall in the same user page share one umem.
*/
if (page->desc.type == IB_UVERBS_BUFFER_TYPE_VA) {
page->desc.addr &= PAGE_MASK;
page->desc.length = PAGE_SIZE;
}
umem = ib_umem_get_desc(context->ibucontext.device, &page->desc, 0);
if (IS_ERR(umem)) {
err = PTR_ERR(umem);
kfree(page);
goto out;
}
/*
* The 8-byte DBR is programmed to the device as one DMA address,
* so it must live in a single contiguous DMA segment.
*/
if (!ib_umem_is_contiguous(umem)) {
ib_umem_release(umem);
kfree(page);
err = -EINVAL;
goto out;
}
page->umem = umem;
if (page->desc.type == IB_UVERBS_BUFFER_TYPE_VA) {
mmgrab(current->mm);
page->mm = current->mm;
}
list_add(&page->list, &context->db_page_list);
found:
db->dma = sg_dma_address(page->umem->sgt_append.sgt.sgl) +
(desc->addr & ~PAGE_MASK);
db->u.user_page = page;
++page->refcnt;
out:
mutex_unlock(&context->db_page_mutex);
return err;
}
int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context,
const struct uverbs_attr_bundle *attrs, u16 attr_id,
unsigned long virt, struct mlx5_db *db)
{
struct ib_uverbs_buffer_desc desc = {
.type = IB_UVERBS_BUFFER_TYPE_VA,
.addr = virt,
.length = MLX5_IB_DBR_SIZE,
};
if (attrs) {
int err;
err = uverbs_get_buffer_desc(attrs, attr_id, &desc);
if (err && err != -ENOENT)
return err;
}
return mlx5_ib_db_map_user_desc(context, &desc, db);
}
void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
{
mutex_lock(&context->db_page_mutex);
if (!--db->u.user_page->refcnt) {
list_del(&db->u.user_page->list);
if (db->u.user_page->mm)
mmdrop(db->u.user_page->mm);
ib_umem_release(db->u.user_page->umem);
kfree(db->u.user_page);
}
mutex_unlock(&context->db_page_mutex);
}
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