/*
* 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 <rdma/ib_umem_odp.h>
#include "uverbs.h"
static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
{
struct scatterlist *sg;
struct page *page;
int i;
if (umem->nmap > 0)
ib_dma_unmap_sg(dev, umem->sg_head.sgl,
umem->nmap,
DMA_BIDIRECTIONAL);
for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
page = sg_page(sg);
if (umem->writable && dirty)
set_page_dirty_lock(page);
put_page(page);
}
sg_free_table(&umem->sg_head);
return;
}
/**
* ib_umem_get - Pin and DMA map userspace memory.
*
* If access flags indicate ODP memory, avoid pinning. Instead, stores
* the mm for future page fault handling in conjunction with MMU notifiers.
*
* @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;
unsigned long locked;
unsigned long lock_limit;
unsigned long cur_base;
unsigned long npages;
int ret;
int i;
DEFINE_DMA_ATTRS(attrs);
struct scatterlist *sg, *sg_list_start;
int need_release = 0;
if (dmasync)
dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
if (!size)
return ERR_PTR(-EINVAL);
/*
* If the combination of the addr and size requested for this memory
* region causes an integer overflow, return error.
*/
if (((addr + size) < addr) ||
PAGE_ALIGN(addr + size) < (addr + size))
return ERR_PTR(-EINVAL);
if (!can_do_mlock())
return ERR_PTR(-EPERM);
umem = kzalloc(sizeof *umem, GFP_KERNEL);
if (!umem)
return ERR_PTR(-ENOMEM);
umem->context = context;
umem->length = size;
umem->address = addr;
umem->page_size = PAGE_SIZE;
umem->pid = get_task_pid(current, PIDTYPE_PID);
/*
* We ask for writable memory if any of the following
* access flags 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_LOCAL_WRITE | IB_ACCESS_REMOTE_WRITE |
IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
if (access & IB_ACCESS_ON_DEMAND) {
ret = ib_umem_odp_get(context, umem);
if (ret) {
kfree(umem);
return ERR_PTR(ret);
}
return umem;
}
umem->odp_data = NULL;
/* We assume the memory is from hugetlb until proved otherwise */
umem->hugetlb = 1;
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 = ib_umem_num_pages(umem);
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;
if (npages == 0) {
ret = -EINVAL;
goto out;
}
ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
if (ret)
goto out;
need_release = 1;
sg_list_start = umem->sg_head.sgl;
while (npages) {
ret = get_user_pages(cur_base,
min_t(unsigned long, npages,
PAGE_SIZE / sizeof (struct page *)),
1, !umem->writable, page_list, vma_list);
if (ret < 0)
goto out;
umem->npages += ret;
cur_base += ret * PAGE_SIZE;
npages -= ret;
for_each_sg(sg_list_start, sg, ret, i) {
if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
umem->hugetlb = 0;
sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
}
/* preparing for next loop */
sg_list_start = sg;
}
umem->nmap = ib_dma_map_sg_attrs(context->device,
umem->sg_head.sgl,
umem->npages,
DMA_BIDIRECTIONAL,
&attrs);
if (umem->nmap <= 0) {
ret = -ENOMEM;
goto out;
}
ret = 0;
out:
if (ret < 0) {
if (need_release)
__ib_umem_release(context->device, umem, 0);
put_pid(umem->pid);
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;
struct task_struct *task;
unsigned long diff;
if (umem->odp_data) {
ib_umem_odp_release(umem);
return;
}
__ib_umem_release(umem->context->device, umem, 1);
task = get_pid_task(umem->pid, PIDTYPE_PID);
put_pid(umem->pid);
if (!task)
goto out;
mm = get_task_mm(task);
put_task_struct(task);
if (!mm)
goto out;
diff = ib_umem_num_pages(umem);
/*
* 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);
mm->pinned_vm -= diff;
up_write(&mm->mmap_sem);
mmput(mm);
out:
kfree(umem);
}
EXPORT_SYMBOL(ib_umem_release);
int ib_umem_page_count(struct ib_umem *umem)
{
int shift;
int i;
int n;
struct scatterlist *sg;
if (umem->odp_data)
return ib_umem_num_pages(umem);
shift = ilog2(umem->page_size);
n = 0;
for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
n += sg_dma_len(sg) >> shift;
return n;
}
EXPORT_SYMBOL(ib_umem_page_count);
/*
* Copy from the given ib_umem's pages to the given buffer.
*
* umem - the umem to copy from
* offset - offset to start copying from
* dst - destination buffer
* length - buffer length
*
* Returns 0 on success, or an error code.
*/
int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,
size_t length)
{
size_t end = offset + length;
int ret;
if (offset > umem->length || length > umem->length - offset) {
pr_err("ib_umem_copy_from not in range. offset: %zd umem length: %zd end: %zd\n",
offset, umem->length, end);
return -EINVAL;
}
ret = sg_pcopy_to_buffer(umem->sg_head.sgl, umem->nmap, dst, length,
offset + ib_umem_offset(umem));
if (ret < 0)
return ret;
else if (ret != length)
return -EINVAL;
else
return 0;
}
EXPORT_SYMBOL(ib_umem_copy_from);
