Commit 52665fe7 authored by Maarten Lankhorst's avatar Maarten Lankhorst Committed by Daniel Vetter
Browse files

drm/i915: Add ww locking around vm_access() 



i915_gem_object_pin_map potentially needs a ww context, so ensure we
have one we can revoke.

Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-35-maarten.lankhorst@linux.intel.com
parent c0525888

drivers/gpu/drm/i915/gem/i915_gem_mman.c

+22 −2
Original line number Diff line number Diff line
@@ -421,7 +421,9 @@ vm_access(struct vm_area_struct *area, unsigned long addr, 
{

	struct i915_mmap_offset *mmo = area->vm_private_data;

	struct drm_i915_gem_object *obj = mmo->obj;

	struct i915_gem_ww_ctx ww;

	void *vaddr;

	int err = 0;



	if (i915_gem_object_is_readonly(obj) && write)

		return -EACCES;
@@ -430,10 +432,18 @@ vm_access(struct vm_area_struct *area, unsigned long addr, 
	if (addr >= obj->base.size)

		return -EINVAL;



	i915_gem_ww_ctx_init(&ww, true);

retry:

	err = i915_gem_object_lock(obj, &ww);

	if (err)

		goto out;



	/* As this is primarily for debugging, let's focus on simplicity */

	vaddr = i915_gem_object_pin_map(obj, I915_MAP_FORCE_WC);

	if (IS_ERR(vaddr))

		return PTR_ERR(vaddr);

	if (IS_ERR(vaddr)) {

		err = PTR_ERR(vaddr);

		goto out;

	}



	if (write) {

		memcpy(vaddr + addr, buf, len);
@@ -443,6 +453,16 @@ vm_access(struct vm_area_struct *area, unsigned long addr, 
	}



	i915_gem_object_unpin_map(obj);

out:

	if (err == -EDEADLK) {

		err = i915_gem_ww_ctx_backoff(&ww);

		if (!err)

			goto retry;

	}

	i915_gem_ww_ctx_fini(&ww);



	if (err)

		return err;



	return len;

}