From 6b1ce0a2009b7e73cf31c1d737f1b8e487f5e8f8 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Mon, 4 Nov 2019 18:38:01 +0100 Subject: [PATCH] drm/ttm: remove ttm_bo_wait_unreserved MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit With nouveau fixed all ttm-using drives have the correct nesting of mmap_sem vs dma_resv, and we can just lock the buffer. Assuming I didn't screw up anything with my audit of course. v2: - Dont forget wu_mutex (Christian König) - Keep the mmap_sem-less wait optimization (Thomas) - Use _lock_interruptible to be good citizens (Thomas) v3: Rebase over fault handler helperification. Reviewed-by: Christian König (v2) Reviewed-by: Thomas Hellström (v2) Signed-off-by: Daniel Vetter Cc: Christian Koenig Cc: Huang Rui Cc: Gerd Hoffmann Cc: "VMware Graphics" Cc: Thomas Hellstrom Link: https://patchwork.freedesktop.org/patch/msgid/20191104173801.2972-3-daniel.vetter@ffwll.ch --- drivers/gpu/drm/ttm/ttm_bo.c | 36 ------------------------------- drivers/gpu/drm/ttm/ttm_bo_util.c | 1 - drivers/gpu/drm/ttm/ttm_bo_vm.c | 18 +++++----------- include/drm/ttm/ttm_bo_api.h | 4 ---- 4 files changed, 5 insertions(+), 54 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index d52fc16266ce..7e7925fecd9e 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -161,7 +161,6 @@ static void ttm_bo_release_list(struct kref *list_kref) dma_fence_put(bo->moving); if (!ttm_bo_uses_embedded_gem_object(bo)) dma_resv_fini(&bo->base._resv); - mutex_destroy(&bo->wu_mutex); bo->destroy(bo); ttm_mem_global_free(&ttm_mem_glob, acc_size); } @@ -1291,7 +1290,6 @@ int ttm_bo_init_reserved(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->type = type; bo->num_pages = num_pages; @@ -1895,37 +1893,3 @@ void ttm_bo_swapout_all(struct ttm_bo_device *bdev) while (ttm_bo_swapout(&ttm_bo_glob, &ctx) == 0); } 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 (!dma_resv_is_locked(bo->base.resv)) - goto out_unlock; - ret = dma_resv_lock_interruptible(bo->base.resv, NULL); - if (ret == -EINTR) - ret = -ERESTARTSYS; - if (unlikely(ret != 0)) - goto out_unlock; - dma_resv_unlock(bo->base.resv); - -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 6b0883a1776e..2b0e5a088da0 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -504,7 +504,6 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo, INIT_LIST_HEAD(&fbo->base.lru); INIT_LIST_HEAD(&fbo->base.swap); INIT_LIST_HEAD(&fbo->base.io_reserve_lru); - mutex_init(&fbo->base.wu_mutex); fbo->base.moving = NULL; drm_vma_node_reset(&fbo->base.base.vma_node); diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index 11863fbdd5d6..91466cfb6f16 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -128,30 +128,22 @@ static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo, vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo, 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 waiting - * for the buffer to become unreserved. - */ if (unlikely(!dma_resv_trylock(bo->base.resv))) { if (vmf->flags & FAULT_FLAG_ALLOW_RETRY) { if (!(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { ttm_bo_get(bo); up_read(&vmf->vma->vm_mm->mmap_sem); - (void) ttm_bo_wait_unreserved(bo); + if (!dma_resv_lock_interruptible(bo->base.resv, + NULL)) + dma_resv_unlock(bo->base.resv); ttm_bo_put(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; + if (dma_resv_lock_interruptible(bo->base.resv, NULL)) + return VM_FAULT_NOPAGE; } return 0; diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index 65e399d280f7..e8b0f0c66059 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -154,7 +154,6 @@ 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 @@ -222,8 +221,6 @@ struct ttm_buffer_object { uint64_t offset; /* GPU address space is independent of CPU word size */ struct sg_table *sg; - - struct mutex wu_mutex; }; /** @@ -707,7 +704,6 @@ ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp, int ttm_bo_swapout(struct ttm_bo_global *glob, struct ttm_operation_ctx *ctx); void ttm_bo_swapout_all(struct ttm_bo_device *bdev); -int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo); /** * ttm_bo_uses_embedded_gem_object - check if the given bo uses the -- 2.25.1