If the bo is idle when calling ttm_bo_pipeline_gutting(), we unnecessarily create a ghost object and push it out to delayed destroy. Fix this by adding a path for idle, and document the function.
Also avoid having the bo end up in a bad state vulnerable to user-space triggered kernel BUGs if the call to ttm_tt_create() fails.
Finally reuse ttm_bo_pipeline_gutting() in ttm_bo_evict().
Cc: Christian König christian.koenig@amd.com Signed-off-by: Thomas Hellström thomas.hellstrom@linux.intel.com --- drivers/gpu/drm/ttm/ttm_bo.c | 20 ++++++------ drivers/gpu/drm/ttm/ttm_bo_util.c | 52 ++++++++++++++++++++++++++++--- drivers/gpu/drm/ttm/ttm_tt.c | 5 +++ include/drm/ttm/ttm_tt.h | 10 ++++++ 4 files changed, 73 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index ca1b098b6a56..a8fa3375b8aa 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -501,10 +501,15 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bdev->funcs->evict_flags(bo, &placement);
if (!placement.num_placement && !placement.num_busy_placement) { - ttm_bo_wait(bo, false, false); + ret = ttm_bo_wait(bo, true, false); + if (ret) + return ret;
- ttm_bo_cleanup_memtype_use(bo); - return ttm_tt_create(bo, false); + /* + * Since we've already synced, this frees backing store + * immediately. + */ + return ttm_bo_pipeline_gutting(bo); }
ret = ttm_bo_mem_space(bo, &placement, &evict_mem, ctx); @@ -974,13 +979,8 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, /* * Remove the backing store if no placement is given. */ - if (!placement->num_placement && !placement->num_busy_placement) { - ret = ttm_bo_pipeline_gutting(bo); - if (ret) - return ret; - - return ttm_tt_create(bo, false); - } + if (!placement->num_placement && !placement->num_busy_placement) + return ttm_bo_pipeline_gutting(bo);
/* * Check whether we need to move buffer. diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 4a7d3d672f9a..7fa9b3a852eb 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -585,26 +585,70 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo, } EXPORT_SYMBOL(ttm_bo_move_accel_cleanup);
+/** + * ttm_bo_pipeline_gutting - purge the contents of a bo + * @bo: The buffer object + * + * Purge the contents of a bo, async if the bo is not idle. + * After a successful call, the bo is left unpopulated in + * system placement. The function may wait uninterruptible + * for idle on OOM. + * + * Return: 0 if successful, negative error code on failure. + */ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo) { static const struct ttm_place sys_mem = { .mem_type = TTM_PL_SYSTEM }; struct ttm_buffer_object *ghost; + struct ttm_tt *ttm; int ret;
- ret = ttm_buffer_object_transfer(bo, &ghost); + /* If already idle, no need for ghost object dance. */ + ret = ttm_bo_wait(bo, false, true); + if (ret != -EBUSY) { + if (!bo->ttm) { + ret = ttm_tt_create(bo, true); + if (ret) + return ret; + } else { + ttm_tt_unpopulate(bo->bdev, bo->ttm); + if (bo->type == ttm_bo_type_device) + ttm_tt_mark_for_clear(bo->ttm); + } + ttm_resource_free(bo, &bo->mem); + ttm_resource_alloc(bo, &sys_mem, &bo->mem); + + return 0; + } + + /* + * We need an unpopulated ttm_tt after giving our current one, + * if any, to the ghost object. And we can't afford to fail + * creating one *after* the operation. + */ + + ttm = bo->ttm; + bo->ttm = NULL; + ret = ttm_tt_create(bo, true); + swap(bo->ttm, ttm); if (ret) return ret;
+ ret = ttm_buffer_object_transfer(bo, &ghost); + if (ret) { + ttm_tt_destroy(bo->bdev, ttm); + return ret; + } + ret = dma_resv_copy_fences(&ghost->base._resv, bo->base.resv); /* Last resort, wait for the BO to be idle when we are OOM */ if (ret) ttm_bo_wait(bo, false, false);
- ttm_resource_alloc(bo, &sys_mem, &bo->mem); - bo->ttm = NULL; - dma_resv_unlock(&ghost->base._resv); ttm_bo_put(ghost); + bo->ttm = ttm; + ttm_resource_alloc(bo, &sys_mem, &bo->mem);
return 0; } diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c index 0e41227116b1..913b330a234b 100644 --- a/drivers/gpu/drm/ttm/ttm_tt.c +++ b/drivers/gpu/drm/ttm/ttm_tt.c @@ -134,6 +134,11 @@ void ttm_tt_destroy_common(struct ttm_device *bdev, struct ttm_tt *ttm) } EXPORT_SYMBOL(ttm_tt_destroy_common);
+void ttm_tt_mark_for_clear(struct ttm_tt *ttm) +{ + ttm->page_flags |= TTM_PAGE_FLAG_ZERO_ALLOC; +} + void ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm) { bdev->funcs->ttm_tt_destroy(bdev, ttm); diff --git a/include/drm/ttm/ttm_tt.h b/include/drm/ttm/ttm_tt.h index 3102059db726..daa9c4cf48bb 100644 --- a/include/drm/ttm/ttm_tt.h +++ b/include/drm/ttm/ttm_tt.h @@ -170,6 +170,16 @@ int ttm_tt_populate(struct ttm_device *bdev, struct ttm_tt *ttm, struct ttm_oper */ void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm);
+/** + * ttm_tt_mark_for_clear - Mark pages for clearing on populate. + * + * @ttm: Pointer to the ttm_tt structure + * + * Marks pages for clearing so that the next time the page vector is + * populated, the pages will be cleared. + */ +void ttm_tt_mark_for_clear(struct ttm_tt *ttm); + void ttm_tt_mgr_init(unsigned long num_pages, unsigned long num_dma32_pages);
struct ttm_kmap_iter *ttm_kmap_iter_tt_init(struct ttm_kmap_iter_tt *iter_tt,