drivers/gpu/drm/omapdrm/omap_gem_helpers.c

   1 /*
   2  * drivers/gpu/drm/omapdrm/omap_gem_helpers.c
   3  *
   4  * Copyright (C) 2011 Texas Instruments
   5  * Author: Rob Clark <rob.clark@linaro.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /* temporary copy of drm_gem_{get,put}_pages() until the
  21  * "drm/gem: add functions to get/put pages" patch is merged..
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/types.h>
  26 #include <linux/shmem_fs.h>
  27
  28 #include <drm/drmP.h>
  29
  30 /**
  31  * drm_gem_get_pages - helper to allocate backing pages for a GEM object
  32  * @obj: obj in question
  33  * @gfpmask: gfp mask of requested pages
  34  */
  35 struct page **_drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask)
  36 {
  37         struct inode *inode;
  38         struct address_space *mapping;
  39         struct page *p, **pages;
  40         int i, npages;
  41
  42         /* This is the shared memory object that backs the GEM resource */
  43         inode = file_inode(obj->filp);
  44         mapping = inode->i_mapping;
  45
  46         npages = obj->size >> PAGE_SHIFT;
  47
  48         pages = drm_malloc_ab(npages, sizeof(struct page *));
  49         if (pages == NULL)
  50                 return ERR_PTR(-ENOMEM);
  51
  52         gfpmask |= mapping_gfp_mask(mapping);
  53
  54         for (i = 0; i < npages; i++) {
  55                 p = shmem_read_mapping_page_gfp(mapping, i, gfpmask);
  56                 if (IS_ERR(p))
  57                         goto fail;
  58                 pages[i] = p;
  59
  60                 /* There is a hypothetical issue w/ drivers that require
  61                  * buffer memory in the low 4GB.. if the pages are un-
  62                  * pinned, and swapped out, they can end up swapped back
  63                  * in above 4GB.  If pages are already in memory, then
  64                  * shmem_read_mapping_page_gfp will ignore the gfpmask,
  65                  * even if the already in-memory page disobeys the mask.
  66                  *
  67                  * It is only a theoretical issue today, because none of
  68                  * the devices with this limitation can be populated with
  69                  * enough memory to trigger the issue.  But this BUG_ON()
  70                  * is here as a reminder in case the problem with
  71                  * shmem_read_mapping_page_gfp() isn't solved by the time
  72                  * it does become a real issue.
  73                  *
  74                  * See this thread: http://lkml.org/lkml/2011/7/11/238
  75                  */
  76                 BUG_ON((gfpmask & __GFP_DMA32) &&
  77                                 (page_to_pfn(p) >= 0x00100000UL));
  78         }
  79
  80         return pages;
  81
  82 fail:
  83         while (i--)
  84                 page_cache_release(pages[i]);
  85
  86         drm_free_large(pages);
  87         return ERR_CAST(p);
  88 }
  89
  90 /**
  91  * drm_gem_put_pages - helper to free backing pages for a GEM object
  92  * @obj: obj in question
  93  * @pages: pages to free
  94  */
  95 void _drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
  96                 bool dirty, bool accessed)
  97 {
  98         int i, npages;
  99
 100         npages = obj->size >> PAGE_SHIFT;
 101
 102         for (i = 0; i < npages; i++) {
 103                 if (dirty)
 104                         set_page_dirty(pages[i]);
 105
 106                 if (accessed)
 107                         mark_page_accessed(pages[i]);
 108
 109                 /* Undo the reference we took when populating the table */
 110                 page_cache_release(pages[i]);
 111         }
 112
 113         drm_free_large(pages);
 114 }
 115
 116 int
 117 _drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size)
 118 {
 119         struct drm_device *dev = obj->dev;
 120         struct drm_gem_mm *mm = dev->mm_private;
 121
 122         return drm_vma_offset_add(&mm->vma_manager, &obj->vma_node,
 123                                   size / PAGE_SIZE);
 124 }