Merge branches 'acpi-hotplug', 'acpi-sysfs' and 'acpi-sleep'

[firefly-linux-kernel-4.4.55.git] / drivers / gpu / drm / ttm / ttm_bo_vm.c

diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index ac617f3ecd0c0de328cf6df1f094a4af641fff72..b249ab9b1eb29c402d407049a42c2fda83b3ffb1 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -107,13 +107,28 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
        /*
         * Work around locking order reversal in fault / nopfn
         * between mmap_sem and bo_reserve: Perform a trylock operation
-        * for reserve, and if it fails, retry the fault after scheduling.
+        * for reserve, and if it fails, retry the fault after waiting
+        * for the buffer to become unreserved.
         */
-
-       ret = ttm_bo_reserve(bo, true, true, false, 0);
+       ret = ttm_bo_reserve(bo, true, true, false, NULL);
        if (unlikely(ret != 0)) {
-               if (ret == -EBUSY)
-                       set_need_resched();
+               if (ret != -EBUSY)
+                       return VM_FAULT_NOPAGE;
+
+               if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) {
+                       if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
+                               up_read(&vma->vm_mm->mmap_sem);
+                               (void) ttm_bo_wait_unreserved(bo);
+                       }
+
+                       return VM_FAULT_RETRY;
+               }
+
+               /*
+                * If we'd want to change locking order to
+                * mmap_sem -> bo::reserve, we'd use a blocking reserve here
+                * instead of retrying the fault...
+                */
                return VM_FAULT_NOPAGE;
        }
 
@@ -123,7 +138,6 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
                case 0:
                        break;
                case -EBUSY:
-                       set_need_resched();
                case -ERESTARTSYS:
                        retval = VM_FAULT_NOPAGE;
                        goto out_unlock;