1 files changed, 74 insertions, 73 deletions

diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index d99dee67353a..aa43265f4f4f 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -165,7 +165,7 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
 	} else {
 		dma_resv_lock(shmem->base.resv, NULL);
 
-		drm_WARN_ON(obj->dev, shmem->vmap_use_count);
+		drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count));
 
 		if (shmem->sgt) {
 			dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
@@ -174,9 +174,10 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
 			kfree(shmem->sgt);
 		}
 		if (shmem->pages)
-			drm_gem_shmem_put_pages(shmem);
+			drm_gem_shmem_put_pages_locked(shmem);
 
-		drm_WARN_ON(obj->dev, shmem->pages_use_count);
+		drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count));
+		drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count));
 
 		dma_resv_unlock(shmem->base.resv);
 	}
@@ -186,21 +187,20 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
 }
 EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
 
-static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
+static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
 {
 	struct drm_gem_object *obj = &shmem->base;
 	struct page **pages;
 
 	dma_resv_assert_held(shmem->base.resv);
 
-	if (shmem->pages_use_count++ > 0)
+	if (refcount_inc_not_zero(&shmem->pages_use_count))
 		return 0;
 
 	pages = drm_gem_get_pages(obj);
 	if (IS_ERR(pages)) {
 		drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n",
 			    PTR_ERR(pages));
-		shmem->pages_use_count = 0;
 		return PTR_ERR(pages);
 	}
 
@@ -216,38 +216,36 @@ static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
 
 	shmem->pages = pages;
 
+	refcount_set(&shmem->pages_use_count, 1);
+
 	return 0;
 }
 
 /*
- * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
+ * drm_gem_shmem_put_pages_locked - Decrease use count on the backing pages for a shmem GEM object
  * @shmem: shmem GEM object
  *
  * This function decreases the use count and puts the backing pages when use drops to zero.
  */
-void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
+void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
 {
 	struct drm_gem_object *obj = &shmem->base;
 
 	dma_resv_assert_held(shmem->base.resv);
 
-	if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
-		return;
-
-	if (--shmem->pages_use_count > 0)
-		return;
-
+	if (refcount_dec_and_test(&shmem->pages_use_count)) {
 #ifdef CONFIG_X86
-	if (shmem->map_wc)
-		set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
+		if (shmem->map_wc)
+			set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
 #endif
 
-	drm_gem_put_pages(obj, shmem->pages,
-			  shmem->pages_mark_dirty_on_put,
-			  shmem->pages_mark_accessed_on_put);
-	shmem->pages = NULL;
+		drm_gem_put_pages(obj, shmem->pages,
+				  shmem->pages_mark_dirty_on_put,
+				  shmem->pages_mark_accessed_on_put);
+		shmem->pages = NULL;
+	}
 }
-EXPORT_SYMBOL(drm_gem_shmem_put_pages);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_put_pages_locked);
 
 int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
 {
@@ -257,7 +255,12 @@ int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
 
 	drm_WARN_ON(shmem->base.dev, drm_gem_is_imported(&shmem->base));
 
-	ret = drm_gem_shmem_get_pages(shmem);
+	if (refcount_inc_not_zero(&shmem->pages_pin_count))
+		return 0;
+
+	ret = drm_gem_shmem_get_pages_locked(shmem);
+	if (!ret)
+		refcount_set(&shmem->pages_pin_count, 1);
 
 	return ret;
 }
@@ -267,7 +270,8 @@ void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
 {
 	dma_resv_assert_held(shmem->base.resv);
 
-	drm_gem_shmem_put_pages(shmem);
+	if (refcount_dec_and_test(&shmem->pages_pin_count))
+		drm_gem_shmem_put_pages_locked(shmem);
 }
 EXPORT_SYMBOL(drm_gem_shmem_unpin_locked);
 
@@ -288,6 +292,9 @@ int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
 
 	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
 
+	if (refcount_inc_not_zero(&shmem->pages_pin_count))
+		return 0;
+
 	ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
 	if (ret)
 		return ret;
@@ -296,7 +303,7 @@ int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
 
 	return ret;
 }
-EXPORT_SYMBOL(drm_gem_shmem_pin);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_pin);
 
 /**
  * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
@@ -311,14 +318,17 @@ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
 
 	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
 
+	if (refcount_dec_not_one(&shmem->pages_pin_count))
+		return;
+
 	dma_resv_lock(shmem->base.resv, NULL);
 	drm_gem_shmem_unpin_locked(shmem);
 	dma_resv_unlock(shmem->base.resv);
 }
-EXPORT_SYMBOL(drm_gem_shmem_unpin);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_unpin);
 
 /*
- * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
+ * drm_gem_shmem_vmap_locked - Create a virtual mapping for a shmem GEM object
  * @shmem: shmem GEM object
  * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
  *       store.
@@ -327,47 +337,43 @@ EXPORT_SYMBOL(drm_gem_shmem_unpin);
  * exists for the buffer backing the shmem GEM object. It hides the differences
  * between dma-buf imported and natively allocated objects.
  *
- * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
+ * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap_locked().
  *
  * Returns:
  * 0 on success or a negative error code on failure.
  */
-int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
-		       struct iosys_map *map)
+int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem,
+			      struct iosys_map *map)
 {
 	struct drm_gem_object *obj = &shmem->base;
 	int ret = 0;
 
 	if (drm_gem_is_imported(obj)) {
 		ret = dma_buf_vmap(obj->dma_buf, map);
-		if (!ret) {
-			if (drm_WARN_ON(obj->dev, map->is_iomem)) {
-				dma_buf_vunmap(obj->dma_buf, map);
-				return -EIO;
-			}
-		}
 	} else {
 		pgprot_t prot = PAGE_KERNEL;
 
 		dma_resv_assert_held(shmem->base.resv);
 
-		if (shmem->vmap_use_count++ > 0) {
+		if (refcount_inc_not_zero(&shmem->vmap_use_count)) {
 			iosys_map_set_vaddr(map, shmem->vaddr);
 			return 0;
 		}
 
-		ret = drm_gem_shmem_get_pages(shmem);
+		ret = drm_gem_shmem_pin_locked(shmem);
 		if (ret)
-			goto err_zero_use;
+			return ret;
 
 		if (shmem->map_wc)
 			prot = pgprot_writecombine(prot);
 		shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
 				    VM_MAP, prot);
-		if (!shmem->vaddr)
+		if (!shmem->vaddr) {
 			ret = -ENOMEM;
-		else
+		} else {
 			iosys_map_set_vaddr(map, shmem->vaddr);
+			refcount_set(&shmem->vmap_use_count, 1);
+		}
 	}
 
 	if (ret) {
@@ -379,28 +385,26 @@ int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
 
 err_put_pages:
 	if (!drm_gem_is_imported(obj))
-		drm_gem_shmem_put_pages(shmem);
-err_zero_use:
-	shmem->vmap_use_count = 0;
+		drm_gem_shmem_unpin_locked(shmem);
 
 	return ret;
 }
-EXPORT_SYMBOL(drm_gem_shmem_vmap);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_vmap_locked);
 
 /*
- * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
+ * drm_gem_shmem_vunmap_locked - Unmap a virtual mapping for a shmem GEM object
  * @shmem: shmem GEM object
  * @map: Kernel virtual address where the SHMEM GEM object was mapped
  *
  * This function cleans up a kernel virtual address mapping acquired by
- * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
- * zero.
+ * drm_gem_shmem_vmap_locked(). The mapping is only removed when the use count
+ * drops to zero.
  *
  * This function hides the differences between dma-buf imported and natively
  * allocated objects.
  */
-void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
-			  struct iosys_map *map)
+void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem,
+				 struct iosys_map *map)
 {
 	struct drm_gem_object *obj = &shmem->base;
 
@@ -409,19 +413,15 @@ void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
 	} else {
 		dma_resv_assert_held(shmem->base.resv);
 
-		if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count))
-			return;
-
-		if (--shmem->vmap_use_count > 0)
-			return;
+		if (refcount_dec_and_test(&shmem->vmap_use_count)) {
+			vunmap(shmem->vaddr);
+			shmem->vaddr = NULL;
 
-		vunmap(shmem->vaddr);
-		drm_gem_shmem_put_pages(shmem);
+			drm_gem_shmem_unpin_locked(shmem);
+		}
 	}
-
-	shmem->vaddr = NULL;
 }
-EXPORT_SYMBOL(drm_gem_shmem_vunmap);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_vunmap_locked);
 
 static int
 drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
@@ -449,7 +449,7 @@ drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
 /* Update madvise status, returns true if not purged, else
  * false or -errno.
  */
-int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
+int drm_gem_shmem_madvise_locked(struct drm_gem_shmem_object *shmem, int madv)
 {
 	dma_resv_assert_held(shmem->base.resv);
 
@@ -460,9 +460,9 @@ int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
 
 	return (madv >= 0);
 }
-EXPORT_SYMBOL(drm_gem_shmem_madvise);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_madvise_locked);
 
-void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
+void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem)
 {
 	struct drm_gem_object *obj = &shmem->base;
 	struct drm_device *dev = obj->dev;
@@ -476,7 +476,7 @@ void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
 	kfree(shmem->sgt);
 	shmem->sgt = NULL;
 
-	drm_gem_shmem_put_pages(shmem);
+	drm_gem_shmem_put_pages_locked(shmem);
 
 	shmem->madv = -1;
 
@@ -492,7 +492,7 @@ void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
 
 	invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1);
 }
-EXPORT_SYMBOL(drm_gem_shmem_purge);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_purge_locked);
 
 /**
  * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
@@ -575,8 +575,8 @@ static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
 	 * mmap'd, vm_open() just grabs an additional reference for the new
 	 * mm the vma is getting copied into (ie. on fork()).
 	 */
-	if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
-		shmem->pages_use_count++;
+	drm_WARN_ON_ONCE(obj->dev,
+			 !refcount_inc_not_zero(&shmem->pages_use_count));
 
 	dma_resv_unlock(shmem->base.resv);
 
@@ -589,7 +589,7 @@ static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
 	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
 
 	dma_resv_lock(shmem->base.resv, NULL);
-	drm_gem_shmem_put_pages(shmem);
+	drm_gem_shmem_put_pages_locked(shmem);
 	dma_resv_unlock(shmem->base.resv);
 
 	drm_gem_vm_close(vma);
@@ -639,7 +639,7 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct
 		return -EINVAL;
 
 	dma_resv_lock(shmem->base.resv, NULL);
-	ret = drm_gem_shmem_get_pages(shmem);
+	ret = drm_gem_shmem_get_pages_locked(shmem);
 	dma_resv_unlock(shmem->base.resv);
 
 	if (ret)
@@ -666,11 +666,12 @@ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
 	if (drm_gem_is_imported(&shmem->base))
 		return;
 
-	drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
-	drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
+	drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count));
+	drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_read(&shmem->pages_use_count));
+	drm_printf_indent(p, indent, "vmap_use_count=%u\n", refcount_read(&shmem->vmap_use_count));
 	drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
 }
-EXPORT_SYMBOL(drm_gem_shmem_print_info);
+EXPORT_SYMBOL_GPL(drm_gem_shmem_print_info);
 
 /**
  * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
@@ -707,7 +708,7 @@ static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_
 
 	drm_WARN_ON(obj->dev, drm_gem_is_imported(obj));
 
-	ret = drm_gem_shmem_get_pages(shmem);
+	ret = drm_gem_shmem_get_pages_locked(shmem);
 	if (ret)
 		return ERR_PTR(ret);
 
@@ -729,7 +730,7 @@ err_free_sgt:
 	sg_free_table(sgt);
 	kfree(sgt);
 err_put_pages:
-	drm_gem_shmem_put_pages(shmem);
+	drm_gem_shmem_put_pages_locked(shmem);
 	return ERR_PTR(ret);
 }