drm/exynos: remove 'pages' and 'page_size' elements in exynos gem buffer

Changelog v2:

Removed redundant check for invalid sgl.
Added check for valid page_offset in the beginning of exynos_drm_gem_map_buf.

Changelog v1:

The 'pages' structure is not required since we can use the 'sgt'. Even for
CONTIG buffers, a SGT is created (which will have just one sgl). This SGT
can be used during mmap instead of 'pages'. The 'page_size' element of the
structure is also not used anywhere and is removed.
This patch also fixes a memory leak where the 'pages' structure was being
allocated during gem buffer allocation but not being freed during deallocate.

Signed-off-by: Prathyush K <prathyush.k@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

5 files changed, 16 insertions, 52 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.c b/drivers/gpu/drm/exynos/exynos_drm_buf.c
index 48c589661cbe..72bf97b96ba0 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_buf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_buf.c
@@ -34,8 +34,6 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
                 unsigned int flags, struct exynos_drm_gem_buf *buf)
 {
         int ret = 0;
-        unsigned int npages, i = 0;
-        struct scatterlist *sgl;
         enum dma_attr attr = DMA_ATTR_FORCE_CONTIGUOUS;
 
         DRM_DEBUG_KMS("%s\n", __FILE__);
@@ -73,22 +71,6 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
                 goto err_free_sgt;
         }
 
-        npages = buf->sgt->nents;
-
-        buf->pages = kzalloc(sizeof(struct page) * npages, GFP_KERNEL);
-        if (!buf->pages) {
-                DRM_ERROR("failed to allocate pages.\n");
-                ret = -ENOMEM;
-                goto err_free_table;
-        }
-
-        sgl = buf->sgt->sgl;
-        while (i < npages) {
-                buf->pages[i] = sg_page(sgl);
-                sgl = sg_next(sgl);
-                i++;
-        }
-
         DRM_DEBUG_KMS("vaddr(0x%lx), dma_addr(0x%lx), size(0x%lx)\n",
                         (unsigned long)buf->kvaddr,
                         (unsigned long)buf->dma_addr,
@@ -96,8 +78,6 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
 
         return ret;
 
-err_free_table:
-        sg_free_table(buf->sgt);
 err_free_sgt:
         kfree(buf->sgt);
         buf->sgt = NULL;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.h b/drivers/gpu/drm/exynos/exynos_drm_buf.h
index 3388e4eb4ba2..25cf16285033 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_buf.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_buf.h
@@ -34,12 +34,12 @@ struct exynos_drm_gem_buf *exynos_drm_init_buf(struct drm_device *dev,
 void exynos_drm_fini_buf(struct drm_device *dev,
                                 struct exynos_drm_gem_buf *buffer);
 
-/* allocate physical memory region and setup sgt and pages. */
+/* allocate physical memory region and setup sgt. */
 int exynos_drm_alloc_buf(struct drm_device *dev,
                                 struct exynos_drm_gem_buf *buf,
                                 unsigned int flags);
 
-/* release physical memory region, sgt and pages. */
+/* release physical memory region, and sgt. */
 void exynos_drm_free_buf(struct drm_device *dev,
                                 unsigned int flags,
                                 struct exynos_drm_gem_buf *buffer);
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
index d9307bd29738..539da9f4eb97 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
@@ -87,8 +87,7 @@ static struct sg_table *
                 goto err_unlock;
         }
 
-        DRM_DEBUG_PRIME("buffer size = 0x%lx page_size = 0x%lx\n",
-                        buf->size, buf->page_size);
+        DRM_DEBUG_PRIME("buffer size = 0x%lx\n", buf->size);
 
 err_unlock:
         mutex_unlock(&dev->struct_mutex);
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 52187aec8692..99227246ce82 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -99,34 +99,23 @@ static int exynos_drm_gem_map_buf(struct drm_gem_object *obj,
         unsigned long pfn;
         int i;
 
-        if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
-                if (!buf->sgt)
-                        return -EINTR;
-
-                sgl = buf->sgt->sgl;
-                for_each_sg(buf->sgt->sgl, sgl, buf->sgt->nents, i) {
-                        if (!sgl) {
-                                DRM_ERROR("invalid SG table\n");
-                                return -EINTR;
-                        }
-                        if (page_offset < (sgl->length >> PAGE_SHIFT))
-                                break;
-                        page_offset -=  (sgl->length >> PAGE_SHIFT);
-                }
-
-                if (i >= buf->sgt->nents) {
-                        DRM_ERROR("invalid page offset\n");
-                        return -EINVAL;
-                }
+        if (!buf->sgt)
+                return -EINTR;
 
-                pfn = __phys_to_pfn(sg_phys(sgl)) + page_offset;
-        } else {
-                if (!buf->pages)
-                        return -EINTR;
+        if (page_offset >= (buf->size >> PAGE_SHIFT)) {
+                DRM_ERROR("invalid page offset\n");
+                return -EINVAL;
+        }
 
-                pfn = page_to_pfn(buf->pages[0]) + page_offset;
+        sgl = buf->sgt->sgl;
+        for_each_sg(buf->sgt->sgl, sgl, buf->sgt->nents, i) {
+                if (page_offset < (sgl->length >> PAGE_SHIFT))
+                        break;
+                page_offset -=  (sgl->length >> PAGE_SHIFT);
         }
 
+        pfn = __phys_to_pfn(sg_phys(sgl)) + page_offset;
+
         return vm_insert_mixed(vma, f_vaddr, pfn);
 }
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
index 4248d7fb698f..d3ea106a9a77 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
@@ -41,8 +41,6 @@
  *      device address with IOMMU.
  * @write: whether pages will be written to by the caller.
  * @sgt: sg table to transfer page data.
- * @pages: contain all pages to allocated memory region.
- * @page_size: could be 4K, 64K or 1MB.
  * @size: size of allocated memory region.
  * @pfnmap: indicate whether memory region from userptr is mmaped with
  *      VM_PFNMAP or not.
@@ -54,8 +52,6 @@ struct exynos_drm_gem_buf {
         struct dma_attrs        dma_attrs;
         unsigned int            write;
         struct sg_table         *sgt;
-        struct page             **pages;
-        unsigned long           page_size;
         unsigned long           size;
         bool                    pfnmap;
 };