[Intel-gfx] [PATCH 04/43] drm/i915: Pin backing pages for pwrite

[Chris Wilson]

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c |   44 ++++++++++++++++++---------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 578b38a..597a1ff 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -60,6 +60,8 @@ static long i915_gem_purge(struct drm_i915_private *dev_priv, long target);
 static void i915_gem_shrink_all(struct drm_i915_private *dev_priv);
 static void i915_gem_object_truncate(struct drm_i915_gem_object *obj);
 
+static int i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj);
+
 static inline void i915_gem_object_fence_lost(struct drm_i915_gem_object *obj)
 {
 	if (obj->tiling_mode)
@@ -673,7 +675,7 @@ shmem_pwrite_fast(struct page *page, int shmem_page_offset, int page_length,
 				       page_length);
 	kunmap_atomic(vaddr);
 
-	return ret;
+	return ret ? -EFAULT : 0;
 }
 
 /* Only difference to the fast-path function is that this can handle bit17
@@ -707,7 +709,7 @@ shmem_pwrite_slow(struct page *page, int shmem_page_offset, int page_length,
 					     page_do_bit17_swizzling);
 	kunmap(page);
 
-	return ret;
+	return ret ? -EFAULT : 0;
 }
 
 static int
@@ -716,7 +718,6 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
 		      struct drm_i915_gem_pwrite *args,
 		      struct drm_file *file)
 {
-	struct address_space *mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping;
 	ssize_t remain;
 	loff_t offset;
 	char __user *user_data;
@@ -725,7 +726,6 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
 	int hit_slowpath = 0;
 	int needs_clflush_after = 0;
 	int needs_clflush_before = 0;
-	int release_page;
 
 	user_data = (char __user *) (uintptr_t) args->data_ptr;
 	remain = args->size;
@@ -751,6 +751,10 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
 	    && obj->cache_level == I915_CACHE_NONE)
 		needs_clflush_before = 1;
 
+	ret = i915_gem_object_get_pages_gtt(obj);
+	if (ret)
+		return ret;
+
 	offset = args->offset;
 	obj->dirty = 1;
 
@@ -776,17 +780,8 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
 			((shmem_page_offset | page_length)
 				& (boot_cpu_data.x86_clflush_size - 1));
 
-		if (obj->pages) {
-			page = obj->pages[offset >> PAGE_SHIFT];
-			release_page = 0;
-		} else {
-			page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
-			if (IS_ERR(page)) {
-				ret = PTR_ERR(page);
-				goto out;
-			}
-			release_page = 1;
-		}
+		page = obj->pages[offset >> PAGE_SHIFT];
+		page_cache_get(page);
 
 		page_do_bit17_swizzling = obj_do_bit17_swizzling &&
 			(page_to_phys(page) & (1 << 17)) != 0;
@@ -798,27 +793,25 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
 		if (ret == 0)
 			goto next_page;
 
-		hit_slowpath = 1;
-		page_cache_get(page);
 		mutex_unlock(&dev->struct_mutex);
-
 		ret = shmem_pwrite_slow(page, shmem_page_offset, page_length,
 					user_data, page_do_bit17_swizzling,
 					partial_cacheline_write,
 					needs_clflush_after);
 
 		mutex_lock(&dev->struct_mutex);
-		page_cache_release(page);
+		hit_slowpath = 1;
+
+		if (ret == 0)
+			ret = i915_gem_object_get_pages_gtt(obj);
+
 next_page:
 		set_page_dirty(page);
 		mark_page_accessed(page);
-		if (release_page)
-			page_cache_release(page);
+		page_cache_release(page);
 
-		if (ret) {
-			ret = -EFAULT;
+		if (ret)
 			goto out;
-		}
 
 		remain -= page_length;
 		user_data += page_length;
@@ -1525,6 +1518,9 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 	if (obj->pages)
 		return 0;
 
+	if (obj->madv != I915_MADV_WILLNEED)
+		return -EINVAL;
+
 	/* Assert that the object is not currently in any GPU domain. As it
 	 * wasn't in the GTT, there shouldn't be any way it could have been in
 	 * a GPU cache
-- 
1.7.10