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Commit b5e4feb6 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Attempt to prefault user pages for pread/pwrite 



... in the hope that it makes the atomic fast paths more likely.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent 202f2fef

drivers/gpu/drm/i915/i915_gem.c

+19 −14
Original line number Original line Diff line number Diff line
@@ -265,19 +265,14 @@ fast_shmem_read(struct page **pages, 
		char __user *data,

		char __user *data,

		int length)

		int length)

{

{

	char __iomem *vaddr;

	int unwritten;

	int unwritten;

	char *vaddr;





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

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

	if (vaddr == NULL)

		return -ENOMEM;

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

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

	kunmap_atomic(vaddr, KM_USER0);

	kunmap_atomic(vaddr, KM_USER0);





	if (unwritten)

	return unwritten ? -EFAULT : 0;

		return -EFAULT;



	return 0;

}

}





static int i915_gem_object_needs_bit17_swizzle(struct drm_gem_object *obj)

static int i915_gem_object_needs_bit17_swizzle(struct drm_gem_object *obj)
@@ -602,6 +597,13 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data, 
		goto out;

		goto out;

	}

	}





	ret = fault_in_pages_writeable((char __user *)(uintptr_t)args->data_ptr,

				       args->size);

	if (ret) {

		ret = -EFAULT;

		goto out;

	}



	if (i915_gem_object_needs_bit17_swizzle(obj)) {

	if (i915_gem_object_needs_bit17_swizzle(obj)) {

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

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

	} else {

	} else {
@@ -668,18 +670,14 @@ fast_shmem_write(struct page **pages, 
		 char __user *data,

		 char __user *data,

		 int length)

		 int length)

{

{

	char __iomem *vaddr;

	int unwritten;

	unsigned long unwritten;

	char *vaddr;





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

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

	if (vaddr == NULL)

		return -ENOMEM;

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

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

	kunmap_atomic(vaddr, KM_USER0);

	kunmap_atomic(vaddr, KM_USER0);





	if (unwritten)

	return unwritten ? -EFAULT : 0;

		return -EFAULT;

	return 0;

}

}





/**

/**
@@ -1078,6 +1076,13 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data, 
		goto out;

		goto out;

	}

	}





	ret = fault_in_pages_readable((char __user *)(uintptr_t)args->data_ptr,

				      args->size);

	if (ret) {

		ret = -EFAULT;

		goto out;

	}



	/* We can only do the GTT pwrite on untiled buffers, as otherwise

	/* We can only do the GTT pwrite on untiled buffers, as otherwise

	 * it would end up going through the fenced access, and we'll get

	 * it would end up going through the fenced access, and we'll get

	 * different detiling behavior between reading and writing.

	 * different detiling behavior between reading and writing.