From 4e5462ee843c883790e9609cf560d88960ea4227 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 7 Mar 2017 13:20:31 +0000 Subject: [PATCH] drm/i915: Store a permanent error in obj->mm.pages Once the object has been truncated, it is unrecoverable. To facilitate detection of this state store the error in obj->mm.pages. This is required for the next patch which should be applied to v4.10 (via stable), so we also need to mark this patch for backporting. In that regard, let's consider this to be a fix/improvement too. v2: Avoid dereferencing the ERR_PTR when freeing the object. Fixes: 1233e2db199d ("drm/i915: Move object backing storage manipulation to its own locking") Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Cc: # v4.10+ Link: http://patchwork.freedesktop.org/patch/msgid/20170307132031.32461-1-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen --- drivers/gpu/drm/i915/i915_gem.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index f7e85fb1464f..f8a5f5c598f1 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2130,6 +2130,7 @@ i915_gem_object_truncate(struct drm_i915_gem_object *obj) */ shmem_truncate_range(file_inode(obj->base.filp), 0, (loff_t)-1); obj->mm.madv = __I915_MADV_PURGED; + obj->mm.pages = ERR_PTR(-EFAULT); } /* Try to discard unwanted pages */ @@ -2229,7 +2230,9 @@ void __i915_gem_object_put_pages(struct drm_i915_gem_object *obj, __i915_gem_object_reset_page_iter(obj); - obj->ops->put_pages(obj, pages); + if (!IS_ERR(pages)) + obj->ops->put_pages(obj, pages); + unlock: mutex_unlock(&obj->mm.lock); } @@ -2449,7 +2452,7 @@ int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj) if (err) return err; - if (unlikely(!obj->mm.pages)) { + if (unlikely(IS_ERR_OR_NULL(obj->mm.pages))) { err = ____i915_gem_object_get_pages(obj); if (err) goto unlock; @@ -2527,7 +2530,7 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj, pinned = true; if (!atomic_inc_not_zero(&obj->mm.pages_pin_count)) { - if (unlikely(!obj->mm.pages)) { + if (unlikely(IS_ERR_OR_NULL(obj->mm.pages))) { ret = ____i915_gem_object_get_pages(obj); if (ret) goto err_unlock;