eba67093f5
This patch attempts to fix up shortcomings with the current calling sequences. 1) There's a fastpath where no locking occurs and only io_mem_reserved is called to obtain needed info for mapping. The fastpath is set per memory type manager. 2) If the fastpath is disabled, io_mem_reserve and io_mem_free will be exactly balanced and not called recursively for the same struct ttm_mem_reg. 3) Optionally the driver can choose to enable a per memory type manager LRU eviction mechanism that, when io_mem_reserve returns -EAGAIN will attempt to kill user-space mappings of memory in that manager to free up needed resources Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Reviewed-by: Ben Skeggs <bskeggs@redhat.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
459 lines
11 KiB
C
459 lines
11 KiB
C
/**************************************************************************
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*
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* Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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**************************************************************************/
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/*
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* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
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*/
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#include <ttm/ttm_module.h>
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#include <ttm/ttm_bo_driver.h>
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#include <ttm/ttm_placement.h>
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#include <linux/mm.h>
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#include <linux/rbtree.h>
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#include <linux/module.h>
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#include <linux/uaccess.h>
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#define TTM_BO_VM_NUM_PREFAULT 16
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static struct ttm_buffer_object *ttm_bo_vm_lookup_rb(struct ttm_bo_device *bdev,
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unsigned long page_start,
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unsigned long num_pages)
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{
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struct rb_node *cur = bdev->addr_space_rb.rb_node;
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unsigned long cur_offset;
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struct ttm_buffer_object *bo;
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struct ttm_buffer_object *best_bo = NULL;
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while (likely(cur != NULL)) {
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bo = rb_entry(cur, struct ttm_buffer_object, vm_rb);
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cur_offset = bo->vm_node->start;
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if (page_start >= cur_offset) {
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cur = cur->rb_right;
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best_bo = bo;
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if (page_start == cur_offset)
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break;
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} else
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cur = cur->rb_left;
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}
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if (unlikely(best_bo == NULL))
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return NULL;
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if (unlikely((best_bo->vm_node->start + best_bo->num_pages) <
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(page_start + num_pages)))
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return NULL;
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return best_bo;
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}
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static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
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vma->vm_private_data;
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struct ttm_bo_device *bdev = bo->bdev;
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unsigned long page_offset;
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unsigned long page_last;
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unsigned long pfn;
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struct ttm_tt *ttm = NULL;
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struct page *page;
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int ret;
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int i;
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unsigned long address = (unsigned long)vmf->virtual_address;
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int retval = VM_FAULT_NOPAGE;
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struct ttm_mem_type_manager *man =
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&bdev->man[bo->mem.mem_type];
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/*
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* Work around locking order reversal in fault / nopfn
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* between mmap_sem and bo_reserve: Perform a trylock operation
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* for reserve, and if it fails, retry the fault after scheduling.
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*/
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ret = ttm_bo_reserve(bo, true, true, false, 0);
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if (unlikely(ret != 0)) {
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if (ret == -EBUSY)
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set_need_resched();
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return VM_FAULT_NOPAGE;
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}
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if (bdev->driver->fault_reserve_notify) {
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ret = bdev->driver->fault_reserve_notify(bo);
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switch (ret) {
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case 0:
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break;
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case -EBUSY:
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set_need_resched();
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case -ERESTARTSYS:
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retval = VM_FAULT_NOPAGE;
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goto out_unlock;
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default:
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retval = VM_FAULT_SIGBUS;
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goto out_unlock;
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}
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}
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/*
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* Wait for buffer data in transit, due to a pipelined
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* move.
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*/
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spin_lock(&bdev->fence_lock);
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if (test_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags)) {
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ret = ttm_bo_wait(bo, false, true, false);
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spin_unlock(&bdev->fence_lock);
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if (unlikely(ret != 0)) {
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retval = (ret != -ERESTARTSYS) ?
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VM_FAULT_SIGBUS : VM_FAULT_NOPAGE;
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goto out_unlock;
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}
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} else
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spin_unlock(&bdev->fence_lock);
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ret = ttm_mem_io_lock(man, true);
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if (unlikely(ret != 0)) {
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retval = VM_FAULT_NOPAGE;
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goto out_unlock;
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}
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ret = ttm_mem_io_reserve_vm(bo);
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if (unlikely(ret != 0)) {
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retval = VM_FAULT_SIGBUS;
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goto out_io_unlock;
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}
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page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
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bo->vm_node->start - vma->vm_pgoff;
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page_last = ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) +
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bo->vm_node->start - vma->vm_pgoff;
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if (unlikely(page_offset >= bo->num_pages)) {
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retval = VM_FAULT_SIGBUS;
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goto out_io_unlock;
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}
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/*
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* Strictly, we're not allowed to modify vma->vm_page_prot here,
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* since the mmap_sem is only held in read mode. However, we
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* modify only the caching bits of vma->vm_page_prot and
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* consider those bits protected by
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* the bo->mutex, as we should be the only writers.
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* There shouldn't really be any readers of these bits except
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* within vm_insert_mixed()? fork?
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*
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* TODO: Add a list of vmas to the bo, and change the
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* vma->vm_page_prot when the object changes caching policy, with
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* the correct locks held.
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*/
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if (bo->mem.bus.is_iomem) {
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vma->vm_page_prot = ttm_io_prot(bo->mem.placement,
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vma->vm_page_prot);
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} else {
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ttm = bo->ttm;
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vma->vm_page_prot = (bo->mem.placement & TTM_PL_FLAG_CACHED) ?
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vm_get_page_prot(vma->vm_flags) :
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ttm_io_prot(bo->mem.placement, vma->vm_page_prot);
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}
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/*
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* Speculatively prefault a number of pages. Only error on
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* first page.
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*/
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for (i = 0; i < TTM_BO_VM_NUM_PREFAULT; ++i) {
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if (bo->mem.bus.is_iomem)
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pfn = ((bo->mem.bus.base + bo->mem.bus.offset) >> PAGE_SHIFT) + page_offset;
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else {
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page = ttm_tt_get_page(ttm, page_offset);
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if (unlikely(!page && i == 0)) {
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retval = VM_FAULT_OOM;
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goto out_io_unlock;
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} else if (unlikely(!page)) {
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break;
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}
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pfn = page_to_pfn(page);
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}
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ret = vm_insert_mixed(vma, address, pfn);
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/*
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* Somebody beat us to this PTE or prefaulting to
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* an already populated PTE, or prefaulting error.
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*/
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if (unlikely((ret == -EBUSY) || (ret != 0 && i > 0)))
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break;
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else if (unlikely(ret != 0)) {
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retval =
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(ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
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goto out_io_unlock;
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}
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address += PAGE_SIZE;
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if (unlikely(++page_offset >= page_last))
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break;
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}
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out_io_unlock:
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ttm_mem_io_unlock(man);
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out_unlock:
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ttm_bo_unreserve(bo);
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return retval;
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}
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static void ttm_bo_vm_open(struct vm_area_struct *vma)
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{
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struct ttm_buffer_object *bo =
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(struct ttm_buffer_object *)vma->vm_private_data;
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(void)ttm_bo_reference(bo);
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}
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static void ttm_bo_vm_close(struct vm_area_struct *vma)
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{
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struct ttm_buffer_object *bo = (struct ttm_buffer_object *)vma->vm_private_data;
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ttm_bo_unref(&bo);
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vma->vm_private_data = NULL;
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}
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static const struct vm_operations_struct ttm_bo_vm_ops = {
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.fault = ttm_bo_vm_fault,
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.open = ttm_bo_vm_open,
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.close = ttm_bo_vm_close
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};
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int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
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struct ttm_bo_device *bdev)
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{
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struct ttm_bo_driver *driver;
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struct ttm_buffer_object *bo;
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int ret;
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read_lock(&bdev->vm_lock);
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bo = ttm_bo_vm_lookup_rb(bdev, vma->vm_pgoff,
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(vma->vm_end - vma->vm_start) >> PAGE_SHIFT);
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if (likely(bo != NULL))
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ttm_bo_reference(bo);
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read_unlock(&bdev->vm_lock);
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if (unlikely(bo == NULL)) {
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printk(KERN_ERR TTM_PFX
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"Could not find buffer object to map.\n");
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return -EINVAL;
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}
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driver = bo->bdev->driver;
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if (unlikely(!driver->verify_access)) {
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ret = -EPERM;
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goto out_unref;
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}
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ret = driver->verify_access(bo, filp);
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if (unlikely(ret != 0))
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goto out_unref;
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vma->vm_ops = &ttm_bo_vm_ops;
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/*
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* Note: We're transferring the bo reference to
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* vma->vm_private_data here.
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*/
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vma->vm_private_data = bo;
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vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
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return 0;
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out_unref:
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ttm_bo_unref(&bo);
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return ret;
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}
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EXPORT_SYMBOL(ttm_bo_mmap);
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int ttm_fbdev_mmap(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
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{
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if (vma->vm_pgoff != 0)
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return -EACCES;
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vma->vm_ops = &ttm_bo_vm_ops;
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vma->vm_private_data = ttm_bo_reference(bo);
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vma->vm_flags |= VM_RESERVED | VM_IO | VM_MIXEDMAP | VM_DONTEXPAND;
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return 0;
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}
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EXPORT_SYMBOL(ttm_fbdev_mmap);
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ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
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const char __user *wbuf, char __user *rbuf, size_t count,
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loff_t *f_pos, bool write)
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{
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struct ttm_buffer_object *bo;
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struct ttm_bo_driver *driver;
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struct ttm_bo_kmap_obj map;
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unsigned long dev_offset = (*f_pos >> PAGE_SHIFT);
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unsigned long kmap_offset;
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unsigned long kmap_end;
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unsigned long kmap_num;
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size_t io_size;
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unsigned int page_offset;
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char *virtual;
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int ret;
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bool no_wait = false;
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bool dummy;
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read_lock(&bdev->vm_lock);
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bo = ttm_bo_vm_lookup_rb(bdev, dev_offset, 1);
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if (likely(bo != NULL))
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ttm_bo_reference(bo);
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read_unlock(&bdev->vm_lock);
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if (unlikely(bo == NULL))
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return -EFAULT;
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driver = bo->bdev->driver;
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if (unlikely(!driver->verify_access)) {
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ret = -EPERM;
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goto out_unref;
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}
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ret = driver->verify_access(bo, filp);
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if (unlikely(ret != 0))
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goto out_unref;
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kmap_offset = dev_offset - bo->vm_node->start;
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if (unlikely(kmap_offset >= bo->num_pages)) {
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ret = -EFBIG;
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goto out_unref;
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}
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page_offset = *f_pos & ~PAGE_MASK;
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io_size = bo->num_pages - kmap_offset;
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io_size = (io_size << PAGE_SHIFT) - page_offset;
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if (count < io_size)
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io_size = count;
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kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
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kmap_num = kmap_end - kmap_offset + 1;
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ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
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switch (ret) {
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case 0:
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break;
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case -EBUSY:
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ret = -EAGAIN;
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goto out_unref;
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default:
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goto out_unref;
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}
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ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
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if (unlikely(ret != 0)) {
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ttm_bo_unreserve(bo);
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goto out_unref;
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}
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virtual = ttm_kmap_obj_virtual(&map, &dummy);
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virtual += page_offset;
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if (write)
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ret = copy_from_user(virtual, wbuf, io_size);
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else
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ret = copy_to_user(rbuf, virtual, io_size);
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ttm_bo_kunmap(&map);
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ttm_bo_unreserve(bo);
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ttm_bo_unref(&bo);
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if (unlikely(ret != 0))
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return -EFBIG;
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*f_pos += io_size;
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return io_size;
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out_unref:
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ttm_bo_unref(&bo);
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return ret;
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}
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ssize_t ttm_bo_fbdev_io(struct ttm_buffer_object *bo, const char __user *wbuf,
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char __user *rbuf, size_t count, loff_t *f_pos,
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bool write)
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{
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struct ttm_bo_kmap_obj map;
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unsigned long kmap_offset;
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unsigned long kmap_end;
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unsigned long kmap_num;
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size_t io_size;
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unsigned int page_offset;
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char *virtual;
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int ret;
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bool no_wait = false;
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bool dummy;
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kmap_offset = (*f_pos >> PAGE_SHIFT);
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if (unlikely(kmap_offset >= bo->num_pages))
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return -EFBIG;
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page_offset = *f_pos & ~PAGE_MASK;
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io_size = bo->num_pages - kmap_offset;
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io_size = (io_size << PAGE_SHIFT) - page_offset;
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if (count < io_size)
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io_size = count;
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kmap_end = (*f_pos + count - 1) >> PAGE_SHIFT;
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kmap_num = kmap_end - kmap_offset + 1;
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ret = ttm_bo_reserve(bo, true, no_wait, false, 0);
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switch (ret) {
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case 0:
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break;
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case -EBUSY:
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return -EAGAIN;
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default:
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return ret;
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}
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ret = ttm_bo_kmap(bo, kmap_offset, kmap_num, &map);
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if (unlikely(ret != 0)) {
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ttm_bo_unreserve(bo);
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return ret;
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}
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virtual = ttm_kmap_obj_virtual(&map, &dummy);
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virtual += page_offset;
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if (write)
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ret = copy_from_user(virtual, wbuf, io_size);
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else
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ret = copy_to_user(rbuf, virtual, io_size);
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ttm_bo_kunmap(&map);
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ttm_bo_unreserve(bo);
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ttm_bo_unref(&bo);
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if (unlikely(ret != 0))
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return ret;
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*f_pos += io_size;
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return io_size;
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}
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