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

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursu...@intel.com>

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.ursu...@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;
 
-- 
2.7.4