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/*
* drivers/staging/omapdrm/omap_gem_helpers.c
*
* Copyright (C) 2011 Texas Instruments
* Author: Rob Clark <rob.clark@linaro.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* temporary copy of drm_gem_{get,put}_pages() until the
* "drm/gem: add functions to get/put pages" patch is merged..
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/shmem_fs.h>
#include <drm/drmP.h>
/**
* drm_gem_get_pages - helper to allocate backing pages for a GEM object
* @obj: obj in question
* @gfpmask: gfp mask of requested pages
*/
struct page ** _drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask)
{
struct inode *inode;
struct address_space *mapping;
struct page *p, **pages;
int i, npages;
/* This is the shared memory object that backs the GEM resource */
inode = obj->filp->f_path.dentry->d_inode;
mapping = inode->i_mapping;
npages = obj->size >> PAGE_SHIFT;
pages = drm_malloc_ab(npages, sizeof(struct page *));
if (pages == NULL)
return ERR_PTR(-ENOMEM);
gfpmask |= mapping_gfp_mask(mapping);
for (i = 0; i < npages; i++) {
p = shmem_read_mapping_page_gfp(mapping, i, gfpmask);
if (IS_ERR(p))
goto fail;
pages[i] = p;
/* There is a hypothetical issue w/ drivers that require
* buffer memory in the low 4GB.. if the pages are un-
* pinned, and swapped out, they can end up swapped back
* in above 4GB. If pages are already in memory, then
* shmem_read_mapping_page_gfp will ignore the gfpmask,
* even if the already in-memory page disobeys the mask.
*
* It is only a theoretical issue today, because none of
* the devices with this limitation can be populated with
* enough memory to trigger the issue. But this BUG_ON()
* is here as a reminder in case the problem with
* shmem_read_mapping_page_gfp() isn't solved by the time
* it does become a real issue.
*
* See this thread: http://lkml.org/lkml/2011/7/11/238
*/
BUG_ON((gfpmask & __GFP_DMA32) &&
(page_to_pfn(p) >= 0x00100000UL));
}
return pages;
fail:
while (i--) {
page_cache_release(pages[i]);
}
drm_free_large(pages);
return ERR_PTR(PTR_ERR(p));
}
/**
* drm_gem_put_pages - helper to free backing pages for a GEM object
* @obj: obj in question
* @pages: pages to free
*/
void _drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
bool dirty, bool accessed)
{
int i, npages;
npages = obj->size >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
if (dirty)
set_page_dirty(pages[i]);
if (accessed)
mark_page_accessed(pages[i]);
/* Undo the reference we took when populating the table */
page_cache_release(pages[i]);
}
drm_free_large(pages);
}
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