drm/i915: Initialise i915_gem_object_create_from_data() directly

Use pagecache_write to avoid shmemfs clearing the pages prior to us
immediately overwriting them with our data.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170317194648.12468-2-chris@chris-wilson.co.uk
Reviewed-by: Matthew Auld <matthew.auld@intel.com>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 3492f8d27c32d56512b090fa1788e947c7728acc..58e1db77d70e9cc3ebfc652d39efe85b665e637e 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4953,9 +4953,9 @@ i915_gem_object_create_from_data(struct drm_i915_private *dev_priv,
                                 const void *data, size_t size)
 {
        struct drm_i915_gem_object *obj;
-       struct sg_table *sg;
-       size_t bytes;
-       int ret;
+       struct file *file;
+       size_t offset;
+       int err;
 
        obj = i915_gem_object_create(dev_priv, round_up(size, PAGE_SIZE));
        if (IS_ERR(obj))
@@ -4963,26 +4963,39 @@ i915_gem_object_create_from_data(struct drm_i915_private *dev_priv,
 
        GEM_BUG_ON(obj->base.write_domain != I915_GEM_DOMAIN_CPU);
 
-       ret = i915_gem_object_pin_pages(obj);
-       if (ret)
-               goto fail;
+       file = obj->base.filp;
+       offset = 0;
+       do {
+               unsigned int len = min_t(typeof(size), size, PAGE_SIZE);
+               struct page *page;
+               void *pgdata, *vaddr;
 
-       sg = obj->mm.pages;
-       bytes = sg_copy_from_buffer(sg->sgl, sg->nents, (void *)data, size);
-       obj->mm.dirty = true; /* Backing store is now out of date */
-       i915_gem_object_unpin_pages(obj);
+               err = pagecache_write_begin(file, file->f_mapping,
+                                           offset, len, 0,
+                                           &page, &pgdata);
+               if (err < 0)
+                       goto fail;
 
-       if (WARN_ON(bytes != size)) {
-               DRM_ERROR("Incomplete copy, wrote %zu of %zu", bytes, size);
-               ret = -EFAULT;
-               goto fail;
-       }
+               vaddr = kmap(page);
+               memcpy(vaddr, data, len);
+               kunmap(page);
+
+               err = pagecache_write_end(file, file->f_mapping,
+                                         offset, len, len,
+                                         page, pgdata);
+               if (err < 0)
+                       goto fail;
+
+               size -= len;
+               data += len;
+               offset += len;
+       } while (size);
 
        return obj;
 
 fail:
        i915_gem_object_put(obj);
-       return ERR_PTR(ret);
+       return ERR_PTR(err);
 }
 
 struct scatterlist *