On Mon, Jul 8, 2013 at 4:45 AM, Patrik Jakobsson
<patrik.r.jakobsson@xxxxxxxxx> wrote:
> On Sun, Jul 7, 2013 at 8:58 PM, Rob Clark <robdclark@xxxxxxxxx> wrote:
>> Basically just extracting some code duplicated in gma500, omapdrm, udl,
>> and upcoming msm driver.
>>
>> Signed-off-by: Rob Clark <robdclark@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/drm_gem.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++
>> include/drm/drmP.h | 4 +++
>> 2 files changed, 95 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>> index 443eeff..853dea6 100644
>> --- a/drivers/gpu/drm/drm_gem.c
>> +++ b/drivers/gpu/drm/drm_gem.c
>> @@ -406,6 +406,97 @@ int drm_gem_create_mmap_offset(struct drm_gem_object *obj)
>> }
>> EXPORT_SYMBOL(drm_gem_create_mmap_offset);
>>
>> +/**
>> + * drm_gem_get_pages - helper to allocate backing pages for a GEM object
>> + * from shmem
>> + * @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 = file_inode(obj->filp);
>> + mapping = inode->i_mapping;
>> +
>> + npages = obj->size >> PAGE_SHIFT;
>
> Theoretical issue, but what if obj->size is not page aligned? Perhaps put a
> roundup(obj->size, PAGE_SIZE) here?
so, drm_gem_object_init() does have:
BUG_ON((size & (PAGE_SIZE - 1)) != 0);
so I was kinda assuming that we can count on the size already being
aligned. But I guess in case someone somehow bypasses
drm_gem_object_init() it wouldn't hurt to round up the size..
BR,
-R
>> +
>> + 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_CAST(p);
>> +}
>> +EXPORT_SYMBOL(drm_gem_get_pages);
>> +
>> +/**
>> + * drm_gem_put_pages - helper to free backing pages for a GEM object
>> + * @obj: obj in question
>> + * @pages: pages to free
>> + * @dirty: if true, pages will be marked as dirty
>> + * @accessed: if true, the pages will be marked as accessed
>> + */
>> +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;
>
> Same thing here.
>
>> +
>> + 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);
>> +}
>> +EXPORT_SYMBOL(drm_gem_put_pages);
>> +
>> /** Returns a reference to the object named by the handle. */
>> struct drm_gem_object *
>> drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
>> diff --git a/include/drm/drmP.h b/include/drm/drmP.h
>> index 3cb1672..7ec3fa4 100644
>> --- a/include/drm/drmP.h
>> +++ b/include/drm/drmP.h
>> @@ -1730,6 +1730,10 @@ void drm_gem_free_mmap_offset(struct drm_gem_object *obj);
>> int drm_gem_create_mmap_offset(struct drm_gem_object *obj);
>> int drm_gem_create_mmap_offset_size(struct drm_gem_object *obj, size_t size);
>>
>> +struct page **drm_gem_get_pages(struct drm_gem_object *obj, gfp_t gfpmask);
>> +void drm_gem_put_pages(struct drm_gem_object *obj, struct page **pages,
>> + bool dirty, bool accessed);
>> +
>> struct drm_gem_object *drm_gem_object_lookup(struct drm_device *dev,
>> struct drm_file *filp,
>> u32 handle);
>> --
>> 1.8.1.4
>
> Looks good otherwise, so for all 5 patches:
> Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@xxxxxxxxx>
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