drm/exynos: stop copying sg table

Already struct exynos_drm_gem_buf has pages of the buffer, so we don't
need to copy from sg table of the buffer to sg table of dma-buf
attachment, just can make sg table from pages of the buffer.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

3 files changed, 20 insertions, 40 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
index d10f9b602bf7..619ecddf35fa 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
@@ -18,7 +18,7 @@
 #include <linux/dma-buf.h>
 
 struct exynos_drm_dmabuf_attachment {
-        struct sg_table sgt;
+        struct sg_table *sgt;
         enum dma_data_direction dir;
         bool is_mapped;
 };
@@ -53,13 +53,15 @@ static void exynos_gem_detach_dma_buf(struct dma_buf *dmabuf,
         if (!exynos_attach)
                 return;
 
-        sgt = &exynos_attach->sgt;
-
-        if (exynos_attach->dir != DMA_NONE)
-                dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
-                                exynos_attach->dir);
+        sgt = exynos_attach->sgt;
+        if (sgt) {
+                if (exynos_attach->dir != DMA_NONE)
+                        dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents,
+                                        exynos_attach->dir);
+                sg_free_table(sgt);
+        }
 
-        sg_free_table(sgt);
+        kfree(sgt);
         kfree(exynos_attach);
         attach->priv = NULL;
 }
@@ -70,16 +72,13 @@ static struct sg_table *
 {
         struct exynos_drm_dmabuf_attachment *exynos_attach = attach->priv;
         struct exynos_drm_gem_obj *gem_obj = dma_buf_to_obj(attach->dmabuf);
-        struct drm_device *dev = gem_obj->base.dev;
         struct exynos_drm_gem_buf *buf;
-        struct scatterlist *rd, *wr;
-        struct sg_table *sgt = NULL;
-        unsigned int i;
-        int nents, ret;
+        struct sg_table *sgt;
+        int npages;
 
         /* just return current sgt if already requested. */
         if (exynos_attach->dir == dir && exynos_attach->is_mapped)
-                return &exynos_attach->sgt;
+                return exynos_attach->sgt;
 
         buf = gem_obj->buffer;
         if (!buf) {
@@ -87,42 +86,29 @@ static struct sg_table *
                 return ERR_PTR(-ENOMEM);
         }
 
-        sgt = &exynos_attach->sgt;
+        npages = buf->size >> PAGE_SHIFT;
 
-        ret = sg_alloc_table(sgt, buf->sgt->orig_nents, GFP_KERNEL);
-        if (ret) {
-                DRM_ERROR("failed to alloc sgt.\n");
-                return ERR_PTR(-ENOMEM);
-        }
-
-        mutex_lock(&dev->struct_mutex);
-
-        rd = buf->sgt->sgl;
-        wr = sgt->sgl;
-        for (i = 0; i < sgt->orig_nents; ++i) {
-                sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
-                rd = sg_next(rd);
-                wr = sg_next(wr);
-        }
+        sgt = drm_prime_pages_to_sg(buf->pages, npages);
+        if (IS_ERR(sgt))
+                goto err;
 
         if (dir != DMA_NONE) {
-                nents = dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir);
-                if (!nents) {
+                if (!dma_map_sg(attach->dev, sgt->sgl, sgt->orig_nents, dir)) {
                         DRM_ERROR("failed to map sgl with iommu.\n");
                         sg_free_table(sgt);
                         sgt = ERR_PTR(-EIO);
-                        goto err_unlock;
+                        goto err;
                 }
         }
 
         exynos_attach->is_mapped = true;
+        exynos_attach->sgt = sgt;
         exynos_attach->dir = dir;
         attach->priv = exynos_attach;
 
         DRM_DEBUG_PRIME("buffer size = 0x%lx\n", buf->size);
 
-err_unlock:
-        mutex_unlock(&dev->struct_mutex);
+err:
         return sgt;
 }
 
@@ -280,7 +266,6 @@ struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
         }
 
         exynos_gem_obj->buffer = buffer;
-        buffer->sgt = sgt;
         exynos_gem_obj->base.import_attach = attach;
 
         DRM_DEBUG_PRIME("dma_addr = %pad, size = 0x%lx\n", &buffer->dma_addr,
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 4d9a09907607..fa04b9add09a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -455,9 +455,6 @@ void exynos_drm_gem_free_object(struct drm_gem_object *obj)
         exynos_gem_obj = to_exynos_gem_obj(obj);
         buf = exynos_gem_obj->buffer;
 
-        if (obj->import_attach)
-                drm_prime_gem_destroy(obj, buf->sgt);
-
         exynos_drm_gem_destroy(to_exynos_gem_obj(obj));
 }
 
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
index 6f42e2248288..5979f22828d4 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
@@ -30,7 +30,6 @@
  *      device address with IOMMU.
  * @write: whether pages will be written to by the caller.
  * @pages: Array of backing pages.
- * @sgt: sg table to transfer page data.
  * @size: size of allocated memory region.
  * @pfnmap: indicate whether memory region from userptr is mmaped with
  *      VM_PFNMAP or not.
@@ -43,7 +42,6 @@ struct exynos_drm_gem_buf {
         struct dma_attrs        dma_attrs;
         unsigned int            write;
         struct page             **pages;
-        struct sg_table         *sgt;
         unsigned long           size;
         bool                    pfnmap;
 };