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Commit e244a443 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/i915: merge shmem_pwrite slow&fast-path 



With the previous rewrite, they've become essential identical.

v2: Simplify the page_do_bit17_swizzling logic as suggested by Chris
Wilson.

Tested-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent dabdfe02

drivers/gpu/drm/i915/i915_gem.c

+33 −93
Original line number Diff line number Diff line
@@ -691,81 +691,8 @@ out_unpin_pages: 
	return ret;

}



/**

 * This is the fast shmem pwrite path, which attempts to directly

 * copy_from_user into the kmapped pages backing the object.

 */

static int

i915_gem_shmem_pwrite_fast(struct drm_device *dev,

			   struct drm_i915_gem_object *obj,

			   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;

	int page_offset, page_length;



	user_data = (char __user *) (uintptr_t) args->data_ptr;

	remain = args->size;



	offset = args->offset;

	obj->dirty = 1;



	while (remain > 0) {

		struct page *page;

		char *vaddr;

		int ret;



		/* Operation in this page

		 *

		 * page_offset = offset within page

		 * page_length = bytes to copy for this page

		 */

		page_offset = offset_in_page(offset);

		page_length = remain;

		if ((page_offset + remain) > PAGE_SIZE)

			page_length = PAGE_SIZE - page_offset;



		page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);

		if (IS_ERR(page))

			return PTR_ERR(page);



		vaddr = kmap_atomic(page);

		ret = __copy_from_user_inatomic(vaddr + page_offset,

						user_data,

						page_length);

		kunmap_atomic(vaddr);



		set_page_dirty(page);

		mark_page_accessed(page);

		page_cache_release(page);



		/* If we get a fault while copying data, then (presumably) our

		 * source page isn't available.  Return the error and we'll

		 * retry in the slow path.

		 */

		if (ret)

			return -EFAULT;



		remain -= page_length;

		user_data += page_length;

		offset += page_length;

	}



	return 0;

}



/**

 * This is the fallback shmem pwrite path, which uses get_user_pages to pin

 * the memory and maps it using kmap_atomic for copying.

 *

 * This avoids taking mmap_sem for faulting on the user's address while the

 * struct_mutex is held.

 */

static int

i915_gem_shmem_pwrite_slow(struct drm_device *dev,

i915_gem_shmem_pwrite(struct drm_device *dev,

		      struct drm_i915_gem_object *obj,

		      struct drm_i915_gem_pwrite *args,

		      struct drm_file *file)
@@ -776,6 +703,7 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, 
	char __user *user_data;

	int shmem_page_offset, page_length, ret = 0;

	int obj_do_bit17_swizzling, page_do_bit17_swizzling;

	int hit_slowpath = 0;



	user_data = (char __user *) (uintptr_t) args->data_ptr;

	remain = args->size;
@@ -785,8 +713,6 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, 
	offset = args->offset;

	obj->dirty = 1;



	mutex_unlock(&dev->struct_mutex);



	while (remain > 0) {

		struct page *page;

		char *vaddr;
@@ -811,6 +737,21 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, 
		page_do_bit17_swizzling = obj_do_bit17_swizzling &&

			(page_to_phys(page) & (1 << 17)) != 0;



		if (!page_do_bit17_swizzling) {

			vaddr = kmap_atomic(page);

			ret = __copy_from_user_inatomic(vaddr + shmem_page_offset,

							user_data,

							page_length);

			kunmap_atomic(vaddr);



			if (ret == 0)

				goto next_page;

		}



		hit_slowpath = 1;



		mutex_unlock(&dev->struct_mutex);



		vaddr = kmap(page);

		if (page_do_bit17_swizzling)

			ret = __copy_from_user_swizzled(vaddr, shmem_page_offset,
@@ -822,6 +763,8 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, 
					       page_length);

		kunmap(page);



		mutex_lock(&dev->struct_mutex);

next_page:

		set_page_dirty(page);

		mark_page_accessed(page);

		page_cache_release(page);
@@ -837,7 +780,7 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, 
	}



out:

	mutex_lock(&dev->struct_mutex);

	if (hit_slowpath) {

		/* Fixup: Kill any reinstated backing storage pages */

		if (obj->madv == __I915_MADV_PURGED)

			i915_gem_object_truncate(obj);
@@ -847,6 +790,7 @@ out: 
			i915_gem_clflush_object(obj);

			intel_gtt_chipset_flush();

		}

	}



	return ret;

}
@@ -939,11 +883,7 @@ out_unpin: 
	if (ret)

		goto out;



	ret = -EFAULT;

	if (!i915_gem_object_needs_bit17_swizzle(obj))

		ret = i915_gem_shmem_pwrite_fast(dev, obj, args, file);

	if (ret == -EFAULT)

		ret = i915_gem_shmem_pwrite_slow(dev, obj, args, file);

	ret = i915_gem_shmem_pwrite(dev, obj, args, file);



out:

	drm_gem_object_unreference(&obj->base);