[PATCH 5/5] drm/i915: Use __sg_alloc_table_from_pages for userptr allocations

Tvrtko Ursulin
2016-10-21T14:11:44Z

With the addition of __sg_alloc_table_from_pages we can control
the maximum coallescing size and eliminate a separate path for
allocating backing store here.

This also makes the tables as compact as possible in all cases.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 9 +++++++++
drivers/gpu/drm/i915/i915_gem.c | 11 +----------
drivers/gpu/drm/i915/i915_gem_userptr.c | 29 +++++++----------------------
3 files changed, 17 insertions(+), 32 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5b2b7f3c6e76..577a3a87f680 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -4001,4 +4001,13 @@ int remap_io_mapping(struct vm_area_struct *vma,
__T; \
})

+static inline unsigned int i915_swiotlb_max_size(void)
+{
+#if IS_ENABLED(CONFIG_SWIOTLB)
+ return swiotlb_nr_tbl() << IO_TLB_SHIFT;
+#else
+ return UINT_MAX;
+#endif
+}
+
#endif
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 4bf675568a37..18125d7279c6 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2205,15 +2205,6 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj)
return 0;
}

-static unsigned int swiotlb_max_size(void)
-{
-#if IS_ENABLED(CONFIG_SWIOTLB)
- return swiotlb_nr_tbl() << IO_TLB_SHIFT;
-#else
- return UINT_MAX;
-#endif
-}
-
static int
i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
{
@@ -2222,7 +2213,7 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
struct address_space *mapping;
struct sg_table *st;
struct page *page, **pages;
- unsigned int max_segment = swiotlb_max_size();
+ unsigned int max_segment = i915_swiotlb_max_size();
int ret;
gfp_t gfp;

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index e537930c64b5..17dca225a3e0 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -397,36 +397,21 @@ struct get_pages_work {
struct task_struct *task;
};

-#if IS_ENABLED(CONFIG_SWIOTLB)
-#define swiotlb_active() swiotlb_nr_tbl()
-#else
-#define swiotlb_active() 0
-#endif
-
static int
st_set_pages(struct sg_table **st, struct page **pvec, int num_pages)
{
- struct scatterlist *sg;
- int ret, n;
+ unsigned int max_segment = i915_swiotlb_max_size();
+ int ret;

*st = kmalloc(sizeof(**st), GFP_KERNEL);
if (*st == NULL)
return -ENOMEM;

- if (swiotlb_active()) {
- ret = sg_alloc_table(*st, num_pages, GFP_KERNEL);
- if (ret)
- goto err;
-
- for_each_sg((*st)->sgl, sg, num_pages, n)
- sg_set_page(sg, pvec[n], PAGE_SIZE, 0);
- } else {
- ret = sg_alloc_table_from_pages(*st, pvec, num_pages,
- 0, num_pages << PAGE_SHIFT,
- GFP_KERNEL);
- if (ret)
- goto err;
- }
+ ret = __sg_alloc_table_from_pages(*st, pvec, num_pages, 0,
+ num_pages << PAGE_SHIFT,
+ GFP_KERNEL, max_segment);
+ if (ret)
+ goto err;

return 0;