diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem_userptr.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_userptr.c | 38 |
1 files changed, 23 insertions, 15 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index c36a84b070b6f..4d712a4db63b4 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -164,7 +164,6 @@ static struct i915_mmu_notifier * i915_mmu_notifier_create(struct mm_struct *mm) { struct i915_mmu_notifier *mn; - int ret; mn = kmalloc(sizeof(*mn), GFP_KERNEL); if (mn == NULL) @@ -179,14 +178,6 @@ i915_mmu_notifier_create(struct mm_struct *mm) return ERR_PTR(-ENOMEM); } - /* Protected by mmap_sem (write-lock) */ - ret = __mmu_notifier_register(&mn->mn, mm); - if (ret) { - destroy_workqueue(mn->wq); - kfree(mn); - return ERR_PTR(ret); - } - return mn; } @@ -210,23 +201,40 @@ i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj) static struct i915_mmu_notifier * i915_mmu_notifier_find(struct i915_mm_struct *mm) { - struct i915_mmu_notifier *mn = mm->mn; + struct i915_mmu_notifier *mn; + int err = 0; mn = mm->mn; if (mn) return mn; + mn = i915_mmu_notifier_create(mm->mm); + if (IS_ERR(mn)) + err = PTR_ERR(mn); + down_write(&mm->mm->mmap_sem); mutex_lock(&mm->i915->mm_lock); - if ((mn = mm->mn) == NULL) { - mn = i915_mmu_notifier_create(mm->mm); - if (!IS_ERR(mn)) - mm->mn = mn; + if (mm->mn == NULL && !err) { + /* Protected by mmap_sem (write-lock) */ + err = __mmu_notifier_register(&mn->mn, mm->mm); + if (!err) { + /* Protected by mm_lock */ + mm->mn = fetch_and_zero(&mn); + } + } else { + /* someone else raced and successfully installed the mmu + * notifier, we can cancel our own errors */ + err = 0; } mutex_unlock(&mm->i915->mm_lock); up_write(&mm->mm->mmap_sem); - return mn; + if (mn) { + destroy_workqueue(mn->wq); + kfree(mn); + } + + return err ? ERR_PTR(err) : mm->mn; } static int |