diff options
author | Roland Dreier <rolandd@cisco.com> | 2007-03-05 00:15:11 (GMT) |
---|---|---|
committer | Roland Dreier <rolandd@cisco.com> | 2007-05-09 01:00:37 (GMT) |
commit | f7c6a7b5d59980b076abbf2ceeb8735591290285 (patch) | |
tree | 29c35b47052bba87f031a4744d8ad12ff5187149 /drivers/infiniband/core/umem.c | |
parent | 36f021b579d195cdc5fa6f3e2bab198b4bf70643 (diff) | |
download | linux-fsl-qoriq-f7c6a7b5d59980b076abbf2ceeb8735591290285.tar.xz |
IB/uverbs: Export ib_umem_get()/ib_umem_release() to modules
Export ib_umem_get()/ib_umem_release() and put low-level drivers in
control of when to call ib_umem_get() to pin and DMA map userspace,
rather than always calling it in ib_uverbs_reg_mr() before calling the
low-level driver's reg_user_mr method.
Also move these functions to be in the ib_core module instead of
ib_uverbs, so that driver modules using them do not depend on
ib_uverbs.
This has a number of advantages:
- It is better design from the standpoint of making generic code a
library that can be used or overridden by device-specific code as
the details of specific devices dictate.
- Drivers that do not need to pin userspace memory regions do not
need to take the performance hit of calling ib_mem_get(). For
example, although I have not tried to implement it in this patch,
the ipath driver should be able to avoid pinning memory and just
use copy_{to,from}_user() to access userspace memory regions.
- Buffers that need special mapping treatment can be identified by
the low-level driver. For example, it may be possible to solve
some Altix-specific memory ordering issues with mthca CQs in
userspace by mapping CQ buffers with extra flags.
- Drivers that need to pin and DMA map userspace memory for things
other than memory regions can use ib_umem_get() directly, instead
of hacks using extra parameters to their reg_phys_mr method. For
example, the mlx4 driver that is pending being merged needs to pin
and DMA map QP and CQ buffers, but it does not need to create a
memory key for these buffers. So the cleanest solution is for mlx4
to call ib_umem_get() in the create_qp and create_cq methods.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/infiniband/core/umem.c')
-rw-r--r-- | drivers/infiniband/core/umem.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c new file mode 100644 index 0000000..48e854c --- /dev/null +++ b/drivers/infiniband/core/umem.c @@ -0,0 +1,273 @@ +/* + * 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. + * + * $Id: uverbs_mem.c 2743 2005-06-28 22:27:59Z roland $ + */ + +#include <linux/mm.h> +#include <linux/dma-mapping.h> + +#include "uverbs.h" + +struct ib_umem_account_work { + struct work_struct work; + struct mm_struct *mm; + unsigned long diff; +}; + + +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) { + if (umem->writable && dirty) + set_page_dirty_lock(chunk->page_list[i].page); + put_page(chunk->page_list[i].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 + */ +struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr, + size_t size, int access) +{ + struct ib_umem *umem; + struct page **page_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; + + 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); + + INIT_LIST_HEAD(&umem->chunk_list); + + page_list = (struct page **) __get_free_page(GFP_KERNEL); + if (!page_list) { + kfree(umem); + return ERR_PTR(-ENOMEM); + } + + npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT; + + down_write(¤t->mm->mmap_sem); + + locked = npages + current->mm->locked_vm; + lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; + + if ((locked > lock_limit) && !capable(CAP_IPC_LOCK)) { + ret = -ENOMEM; + goto out; + } + + cur_base = addr & PAGE_MASK; + + while (npages) { + ret = get_user_pages(current, current->mm, cur_base, + min_t(int, npages, + PAGE_SIZE / sizeof (struct page *)), + 1, !umem->writable, page_list, NULL); + + 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); + for (i = 0; i < chunk->nents; ++i) { + chunk->page_list[i].page = page_list[i + off]; + chunk->page_list[i].offset = 0; + chunk->page_list[i].length = PAGE_SIZE; + } + + chunk->nmap = ib_dma_map_sg(context->device, + &chunk->page_list[0], + chunk->nents, + DMA_BIDIRECTIONAL); + if (chunk->nmap <= 0) { + for (i = 0; i < chunk->nents; ++i) + put_page(chunk->page_list[i].page); + 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->locked_vm = locked; + + up_write(¤t->mm->mmap_sem); + 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_account_work *work = + container_of(_work, struct ib_umem_account_work, work); + + down_write(&work->mm->mmap_sem); + work->mm->locked_vm -= work->diff; + up_write(&work->mm->mmap_sem); + mmput(work->mm); + kfree(work); +} + +/** + * 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_umem_account_work *work; + 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) + return; + + diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT; + kfree(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 && !down_write_trylock(&mm->mmap_sem)) { + work = kmalloc(sizeof *work, GFP_KERNEL); + if (!work) { + mmput(mm); + return; + } + + INIT_WORK(&work->work, ib_umem_account); + work->mm = mm; + work->diff = diff; + + schedule_work(&work->work); + return; + } else + down_write(&mm->mmap_sem); + + current->mm->locked_vm -= diff; + up_write(&mm->mmap_sem); + mmput(mm); +} +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); |