/* * 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);