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[PATCH] IB uverbs: memory pinning implementation
Add support for pinning userspace memory regions and returning a list of pages in the region. This includes tracking pinned memory against vm_locked and preventing unprivileged users from exceeding RLIMIT_MEMLOCK. Signed-off-by: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Roland Dreier
Linus Torvalds
parent
bc38a6abdd
commit
eb8ffbfed5
1 changed files with 221 additions and 0 deletions
221
drivers/infiniband/core/uverbs_mem.c
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221
drivers/infiniband/core/uverbs_mem.c
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/*
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* Copyright (c) 2005 Topspin Communications. All rights reserved.
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* Copyright (c) 2005 Cisco Systems. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* $Id: uverbs_mem.c 2743 2005-06-28 22:27:59Z roland $
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*/
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#include <linux/mm.h>
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#include <linux/dma-mapping.h>
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#include "uverbs.h"
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struct ib_umem_account_work {
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struct work_struct work;
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struct mm_struct *mm;
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unsigned long diff;
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};
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static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
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{
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struct ib_umem_chunk *chunk, *tmp;
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int i;
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list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) {
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dma_unmap_sg(dev->dma_device, chunk->page_list,
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chunk->nents, DMA_BIDIRECTIONAL);
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for (i = 0; i < chunk->nents; ++i) {
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if (umem->writable && dirty)
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set_page_dirty_lock(chunk->page_list[i].page);
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put_page(chunk->page_list[i].page);
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}
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kfree(chunk);
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}
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}
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int ib_umem_get(struct ib_device *dev, struct ib_umem *mem,
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void *addr, size_t size, int write)
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{
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struct page **page_list;
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struct ib_umem_chunk *chunk;
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unsigned long locked;
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unsigned long lock_limit;
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unsigned long cur_base;
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unsigned long npages;
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int ret = 0;
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int off;
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int i;
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if (!can_do_mlock())
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return -EPERM;
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page_list = (struct page **) __get_free_page(GFP_KERNEL);
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if (!page_list)
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return -ENOMEM;
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mem->user_base = (unsigned long) addr;
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mem->length = size;
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mem->offset = (unsigned long) addr & ~PAGE_MASK;
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mem->page_size = PAGE_SIZE;
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mem->writable = write;
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INIT_LIST_HEAD(&mem->chunk_list);
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npages = PAGE_ALIGN(size + mem->offset) >> PAGE_SHIFT;
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down_write(¤t->mm->mmap_sem);
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locked = npages + current->mm->locked_vm;
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lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
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if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) {
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ret = -ENOMEM;
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goto out;
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}
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cur_base = (unsigned long) addr & PAGE_MASK;
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while (npages) {
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ret = get_user_pages(current, current->mm, cur_base,
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min_t(int, npages,
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PAGE_SIZE / sizeof (struct page *)),
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1, !write, page_list, NULL);
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if (ret < 0)
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goto out;
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cur_base += ret * PAGE_SIZE;
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npages -= ret;
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off = 0;
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while (ret) {
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chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) *
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min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK),
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GFP_KERNEL);
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if (!chunk) {
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ret = -ENOMEM;
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goto out;
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}
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chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK);
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for (i = 0; i < chunk->nents; ++i) {
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chunk->page_list[i].page = page_list[i + off];
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chunk->page_list[i].offset = 0;
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chunk->page_list[i].length = PAGE_SIZE;
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}
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chunk->nmap = dma_map_sg(dev->dma_device,
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&chunk->page_list[0],
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chunk->nents,
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DMA_BIDIRECTIONAL);
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if (chunk->nmap <= 0) {
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for (i = 0; i < chunk->nents; ++i)
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put_page(chunk->page_list[i].page);
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kfree(chunk);
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ret = -ENOMEM;
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goto out;
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}
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ret -= chunk->nents;
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off += chunk->nents;
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list_add_tail(&chunk->list, &mem->chunk_list);
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}
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ret = 0;
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}
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out:
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if (ret < 0)
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__ib_umem_release(dev, mem, 0);
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else
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current->mm->locked_vm = locked;
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up_write(¤t->mm->mmap_sem);
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free_page((unsigned long) page_list);
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return ret;
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}
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void ib_umem_release(struct ib_device *dev, struct ib_umem *umem)
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{
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__ib_umem_release(dev, umem, 1);
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down_write(¤t->mm->mmap_sem);
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current->mm->locked_vm -=
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PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
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up_write(¤t->mm->mmap_sem);
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}
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static void ib_umem_account(void *work_ptr)
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{
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struct ib_umem_account_work *work = work_ptr;
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down_write(&work->mm->mmap_sem);
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work->mm->locked_vm -= work->diff;
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up_write(&work->mm->mmap_sem);
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mmput(work->mm);
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kfree(work);
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}
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void ib_umem_release_on_close(struct ib_device *dev, struct ib_umem *umem)
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{
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struct ib_umem_account_work *work;
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struct mm_struct *mm;
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__ib_umem_release(dev, umem, 1);
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mm = get_task_mm(current);
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if (!mm)
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return;
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/*
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* We may be called with the mm's mmap_sem already held. This
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* can happen when a userspace munmap() is the call that drops
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* the last reference to our file and calls our release
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* method. If there are memory regions to destroy, we'll end
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* up here and not be able to take the mmap_sem. Therefore we
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* defer the vm_locked accounting to the system workqueue.
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*/
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work = kmalloc(sizeof *work, GFP_KERNEL);
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if (!work)
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return;
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INIT_WORK(&work->work, ib_umem_account, work);
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work->mm = mm;
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work->diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
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schedule_work(&work->work);
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}
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