/*
* Copyright (c) 2005 Topspin Communications. All rights reserved.
* Copyright (c) 2005 Cisco Systems. All rights reserved.
* Copyright (c) 2005 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/mm.h>
#include <linux/dma-mapping.h>
#include <linux/sched.h>
#include <linux/export.h>
#include <linux/hugetlb.h>
#include <linux/dma-attrs.h>
#include <linux/slab.h>
#include "uverbs.h"
#define IB_UMEM_MAX_PAGE_CHUNK \
((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) / \
((void *) &((struct ib_umem_chunk *) 0)->page_list[1] - \
(void *) &((struct ib_umem_chunk *) 0)->page_list[0]))
static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
{
struct ib_umem_chunk *chunk, *tmp;
int i;
list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) {
ib_dma_unmap_sg(dev, chunk->page_list,
chunk->nents, DMA_BIDIRECTIONAL);
for (i = 0; i < chunk->nents; ++i) {
struct page *page = sg_page(&chunk->page_list[i]);
if (umem->writable && dirty)
set_page_dirty_lock(page);
put_page(page);
}
kfree(chunk);
}
}
/**
* ib_umem_get - Pin and DMA map userspace memory.
* @context: userspace context to pin memory for
* @addr: userspace virtual address to start at
* @size: length of region to pin
* @access: IB_ACCESS_xxx flags for memory being pinned
* @dmasync: flush in-flight DMA when the memory region is written
*/
struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
size_t size, int access, int dmasync)
{
struct ib_umem *umem;
struct page **page_list;
struct vm_area_struct **vma_list;
struct ib_umem_chunk *chunk;
unsigned long locked;
unsigned long lock_limit;
unsigned long cur_base;
unsigned long npages;
int ret;
int off;
int i;
DEFINE_DMA_ATTRS(attrs);
if (dmasync)
dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
if (!can_do_mlock())
return ERR_PTR(-EPERM);
umem = kmalloc(sizeof *umem, GFP_KERNEL);
if (!umem)
return ERR_PTR(-ENOMEM);
umem->context = context;
umem->length = size;
umem->offset = addr & ~PAGE_MASK;
umem->page_size = PAGE_SIZE;
/*
* We ask for writable memory if any access flags other than
* "remote read" are set. "Local write" and "remote write"
* obviously require write access. "Remote atomic" can do
* things like fetch and add, which will modify memory, and
* "MW bind" can change permissions by binding a window.
*/
umem->writable = !!(access & ~IB_ACCESS_REMOTE_READ);
/* We assume the memory is from hugetlb until proved otherwise */
umem->hugetlb = 1;
INIT_LIST_HEAD(&umem->chunk_list);
page_list = (struct page **) __get_free_page(GFP_KERNEL);
if (!page_list) {
kfree(umem);
return ERR_PTR(-ENOMEM);
}
/*
* if we can't alloc the vma_list, it's not so bad;
* just assume the memory is not hugetlb memory
*/
vma_list = (struct vm_area_struct **) __get_free_page(GFP_KERNEL);
if (!vma_list)
umem->hugetlb = 0;
npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT;
down_write(¤t->mm->mmap_sem);
locked = npages + current->mm->pinned_vm;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
ret = -ENOMEM;
goto out;
}
cur_base = addr & PAGE_MASK;
ret = 0;
while (npages) {
ret = get_user_pages(current, current->mm, cur_base,
min_t(unsigned long, npages,
PAGE_SIZE / sizeof (struct page *)),
1, !umem->writable, page_list, vma_list);
if (ret < 0)
goto out;
cur_base += ret * PAGE_SIZE;
npages -= ret;
off = 0;
while (ret) {
chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) *
min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK),
GFP_KERNEL);
if (!chunk) {
ret = -ENOMEM;
goto out;
}
chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK);
sg_init_table(chunk->page_list, chunk->nents);
for (i = 0; i < chunk->nents; ++i) {
if (vma_list &&
!is_vm_hugetlb_page(vma_list[i + off]))
umem->hugetlb = 0;
sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0);
}
chunk->nmap = ib_dma_map_sg_attrs(context->device,
&chunk->page_list[0],
chunk->nents,
DMA_BIDIRECTIONAL,
&attrs);
if (chunk->nmap <= 0) {
for (i = 0; i < chunk->nents; ++i)
put_page(sg_page(&chunk->page_list[i]));
kfree(chunk);
ret = -ENOMEM;
goto out;
}
ret -= chunk->nents;
off += chunk->nents;
list_add_tail(&chunk->list, &umem->chunk_list);
}
ret = 0;
}
out:
if (ret < 0) {
__ib_umem_release(context->device, umem, 0);
kfree(umem);
} else
current->mm->pinned_vm = locked;
up_write(¤t->mm->mmap_sem);
if (vma_list)
free_page((unsigned long) vma_list);
free_page((unsigned long) page_list);
return ret < 0 ? ERR_PTR(ret) : umem;
}
EXPORT_SYMBOL(ib_umem_get);
static void ib_umem_account(struct work_struct *work)
{
struct ib_umem *umem = container_of(work, struct ib_umem, work);
down_write(&umem->mm->mmap_sem);
umem->mm->pinned_vm -= umem->diff;
up_write(&umem->mm->mmap_sem);
mmput(umem->mm);
kfree(umem);
}
/**
* ib_umem_release - release memory pinned with ib_umem_get
* @umem: umem struct to release
*/
void ib_umem_release(struct ib_umem *umem)
{
struct ib_ucontext *context = umem->context;
struct mm_struct *mm;
unsigned long diff;
__ib_umem_release(umem->context->device, umem, 1);
mm = get_task_mm(current);
if (!mm) {
kfree(umem);
return;
}
diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
/*
* We may be called with the mm's mmap_sem already held. This
* can happen when a userspace munmap() is the call that drops
* the last reference to our file and calls our release
* method. If there are memory regions to destroy, we'll end
* up here and not be able to take the mmap_sem. In that case
* we defer the vm_locked accounting to the system workqueue.
*/
if (context->closing) {
if (!down_write_trylock(&mm->mmap_sem)) {
INIT_WORK(&umem->work, ib_umem_account);
umem->mm = mm;
umem->diff = diff;
queue_work(ib_wq, &umem->work);
return;
}
} else
down_write(&mm->mmap_sem);
current->mm->pinned_vm -= diff;
up_write(&mm->mmap_sem);
mmput(mm);
kfree(umem);
}
EXPORT_SYMBOL(ib_umem_release);
int ib_umem_page_count(struct ib_umem *umem)
{
struct ib_umem_chunk *chunk;
int shift;
int i;
int n;
shift = ilog2(umem->page_size);
n = 0;
list_for_each_entry(chunk, &umem->chunk_list, list)
for (i = 0; i < chunk->nmap; ++i)
n += sg_dma_len(&chunk->page_list[i]) >> shift;
return n;
}
EXPORT_SYMBOL(ib_umem_page_count);
