Merge branch 'ttm-fixes-3.13' of git://people.freedesktop.org/~thomash/linux into...

The set_need_resched() removal fix and yet another fix in
ttm_bo_move_memcpy().

* 'ttm-fixes-3.13' of git://people.freedesktop.org/~thomash/linux:
  drm/ttm: Remove set_need_resched from the ttm fault handler
  drm/ttm: Don't move non-existing data

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 8d5a646ebe6ae9ef0a924145885ce897d1260e1b..07e02c4bf5a8e0def00e120a14b5ada2d1cfaa97 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -151,7 +151,7 @@ static void ttm_bo_release_list(struct kref *list_kref)
        atomic_dec(&bo->glob->bo_count);
        if (bo->resv == &bo->ttm_resv)
                reservation_object_fini(&bo->ttm_resv);
-
+       mutex_destroy(&bo->wu_mutex);
        if (bo->destroy)
                bo->destroy(bo);
        else {
@@ -1123,6 +1123,7 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
        INIT_LIST_HEAD(&bo->ddestroy);
        INIT_LIST_HEAD(&bo->swap);
        INIT_LIST_HEAD(&bo->io_reserve_lru);
+       mutex_init(&bo->wu_mutex);
        bo->bdev = bdev;
        bo->glob = bdev->glob;
        bo->type = type;
@@ -1704,3 +1705,35 @@ void ttm_bo_swapout_all(struct ttm_bo_device *bdev)
                ;
 }
 EXPORT_SYMBOL(ttm_bo_swapout_all);
+
+/**
+ * ttm_bo_wait_unreserved - interruptible wait for a buffer object to become
+ * unreserved
+ *
+ * @bo: Pointer to buffer
+ */
+int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo)
+{
+       int ret;
+
+       /*
+        * In the absense of a wait_unlocked API,
+        * Use the bo::wu_mutex to avoid triggering livelocks due to
+        * concurrent use of this function. Note that this use of
+        * bo::wu_mutex can go away if we change locking order to
+        * mmap_sem -> bo::reserve.
+        */
+       ret = mutex_lock_interruptible(&bo->wu_mutex);
+       if (unlikely(ret != 0))
+               return -ERESTARTSYS;
+       if (!ww_mutex_is_locked(&bo->resv->lock))
+               goto out_unlock;
+       ret = ttm_bo_reserve_nolru(bo, true, false, false, NULL);
+       if (unlikely(ret != 0))
+               goto out_unlock;
+       ww_mutex_unlock(&bo->resv->lock);
+
+out_unlock:
+       mutex_unlock(&bo->wu_mutex);
+       return ret;
+}

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 4834c463c38bdf04d02049f5ca324d152fb6f57d..15b86a94949dcb875d3cd716322875ad8c763e88 100644 (file)
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -350,10 +350,13 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
                goto out2;
 
        /*
-        * Move nonexistent data. NOP.
+        * Don't move nonexistent data. Clear destination instead.
         */
-       if (old_iomap == NULL && ttm == NULL)
+       if (old_iomap == NULL &&
+           (ttm == NULL || ttm->state == tt_unpopulated)) {
+               memset_io(new_iomap, 0, new_mem->num_pages*PAGE_SIZE);
                goto out2;
+       }
 
        /*
         * TTM might be null for moves within the same region.

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;

diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 751eaffbf0d5fe5ef758254ceba1fe706af4423d..ee127ec33c608b06899ee9d69807f9918a78f2c5 100644 (file)
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -169,6 +169,7 @@ struct ttm_tt;
  * @offset: The current GPU offset, which can have different meanings
  * depending on the memory type. For SYSTEM type memory, it should be 0.
  * @cur_placement: Hint of current placement.
+ * @wu_mutex: Wait unreserved mutex.
  *
  * Base class for TTM buffer object, that deals with data placement and CPU
  * mappings. GPU mappings are really up to the driver, but for simpler GPUs
@@ -250,6 +251,7 @@ struct ttm_buffer_object {
 
        struct reservation_object *resv;
        struct reservation_object ttm_resv;
+       struct mutex wu_mutex;
 };
 
 /**
@@ -702,5 +704,5 @@ extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
                         size_t count, loff_t *f_pos, bool write);
 
 extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
-
+extern int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo);
 #endif