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Commit 4f27b75d authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: rearrange mutex acquisition for pread 



... to avoid the double acquisition along fast[er] paths.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent fbd5a26d

drivers/gpu/drm/i915/i915_gem.c

+43 −56
Original line number Diff line number Diff line
@@ -265,14 +265,14 @@ fast_shmem_read(struct page **pages, 
		char __user *data,

		int length)

{

	int unwritten;

	char *vaddr;

	int ret;



	vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT], KM_USER0);

	unwritten = __copy_to_user_inatomic(data, vaddr + page_offset, length);

	ret = __copy_to_user_inatomic(data, vaddr + page_offset, length);

	kunmap_atomic(vaddr, KM_USER0);



	return unwritten ? -EFAULT : 0;

	return ret;

}



static int i915_gem_object_needs_bit17_swizzle(struct drm_gem_object *obj)
@@ -366,24 +366,10 @@ i915_gem_shmem_pread_fast(struct drm_device *dev, struct drm_gem_object *obj, 
	loff_t offset, page_base;

	char __user *user_data;

	int page_offset, page_length;

	int ret;



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

	remain = args->size;



	ret = i915_mutex_lock_interruptible(dev);

	if (ret)

		return ret;



	ret = i915_gem_object_get_pages(obj, 0);

	if (ret != 0)

		goto fail_unlock;



	ret = i915_gem_object_set_cpu_read_domain_range(obj, args->offset,

							args->size);

	if (ret != 0)

		goto fail_put_pages;



	obj_priv = to_intel_bo(obj);

	offset = args->offset;
@@ -400,23 +386,17 @@ i915_gem_shmem_pread_fast(struct drm_device *dev, struct drm_gem_object *obj, 
		if ((page_offset + remain) > PAGE_SIZE)

			page_length = PAGE_SIZE - page_offset;



		ret = fast_shmem_read(obj_priv->pages,

		if (fast_shmem_read(obj_priv->pages,

				    page_base, page_offset,

				      user_data, page_length);

		if (ret)

			goto fail_put_pages;

				    user_data, page_length))

			return -EFAULT;



		remain -= page_length;

		user_data += page_length;

		offset += page_length;

	}



fail_put_pages:

	i915_gem_object_put_pages(obj);

fail_unlock:

	mutex_unlock(&dev->struct_mutex);



	return ret;

	return 0;

}



static int
@@ -477,33 +457,28 @@ i915_gem_shmem_pread_slow(struct drm_device *dev, struct drm_gem_object *obj, 
	last_data_page = (data_ptr + args->size - 1) / PAGE_SIZE;

	num_pages = last_data_page - first_data_page + 1;



	user_pages = drm_calloc_large(num_pages, sizeof(struct page *));

	user_pages = drm_malloc_ab(num_pages, sizeof(struct page *));

	if (user_pages == NULL)

		return -ENOMEM;



	mutex_unlock(&dev->struct_mutex);

	down_read(&mm->mmap_sem);

	pinned_pages = get_user_pages(current, mm, (uintptr_t)args->data_ptr,

				      num_pages, 1, 0, user_pages, NULL);

	up_read(&mm->mmap_sem);

	mutex_lock(&dev->struct_mutex);

	if (pinned_pages < num_pages) {

		ret = -EFAULT;

		goto fail_put_user_pages;

		goto out;

	}



	do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);



	ret = i915_mutex_lock_interruptible(dev);

	if (ret)

		goto fail_put_user_pages;



	ret = i915_gem_object_get_pages_or_evict(obj);

	ret = i915_gem_object_set_cpu_read_domain_range(obj,

							args->offset,

							args->size);

	if (ret)

		goto fail_unlock;

		goto out;



	ret = i915_gem_object_set_cpu_read_domain_range(obj, args->offset,

							args->size);

	if (ret != 0)

		goto fail_put_pages;

	do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);



	obj_priv = to_intel_bo(obj);

	offset = args->offset;
@@ -548,11 +523,7 @@ i915_gem_shmem_pread_slow(struct drm_device *dev, struct drm_gem_object *obj, 
		offset += page_length;

	}



fail_put_pages:

	i915_gem_object_put_pages(obj);

fail_unlock:

	mutex_unlock(&dev->struct_mutex);

fail_put_user_pages:

out:

	for (i = 0; i < pinned_pages; i++) {

		SetPageDirty(user_pages[i]);

		page_cache_release(user_pages[i]);
@@ -581,6 +552,12 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data, 
		return -ENOENT;

	obj_priv = to_intel_bo(obj);



	ret = i915_mutex_lock_interruptible(dev);

	if (ret) {

		drm_gem_object_unreference_unlocked(obj);

		return ret;

	}



	/* Bounds check source.  */

	if (args->offset > obj->size || args->size > obj->size - args->offset) {

		ret = -EINVAL;
@@ -604,17 +581,27 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data, 
		goto out;

	}



	if (i915_gem_object_needs_bit17_swizzle(obj)) {

		ret = i915_gem_shmem_pread_slow(dev, obj, args, file_priv);

	} else {

	ret = i915_gem_object_get_pages_or_evict(obj);

	if (ret)

		goto out;



	ret = i915_gem_object_set_cpu_read_domain_range(obj,

							args->offset,

							args->size);

	if (ret)

		goto out_put;



	ret = -EFAULT;

	if (!i915_gem_object_needs_bit17_swizzle(obj))

		ret = i915_gem_shmem_pread_fast(dev, obj, args, file_priv);

		if (ret != 0)

			ret = i915_gem_shmem_pread_slow(dev, obj, args,

							file_priv);

	}

	if (ret == -EFAULT)

		ret = i915_gem_shmem_pread_slow(dev, obj, args, file_priv);



out_put:

	i915_gem_object_put_pages(obj);

out:

	drm_gem_object_unreference_unlocked(obj);

	drm_gem_object_unreference(obj);

	mutex_unlock(&dev->struct_mutex);

	return ret;

}
@@ -908,7 +895,7 @@ i915_gem_shmem_pwrite_slow(struct drm_device *dev, struct drm_gem_object *obj, 
	last_data_page = (data_ptr + args->size - 1) / PAGE_SIZE;

	num_pages = last_data_page - first_data_page + 1;



	user_pages = drm_calloc_large(num_pages, sizeof(struct page *));

	user_pages = drm_malloc_ab(num_pages, sizeof(struct page *));

	if (user_pages == NULL)

		return -ENOMEM;