From patchwork Tue Nov 6 13:48:28 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maarten Lankhorst X-Patchwork-Id: 1704451 Return-Path: X-Original-To: patchwork-dri-devel@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by patchwork1.kernel.org (Postfix) with ESMTP id E37193FCF7 for ; Tue, 6 Nov 2012 13:48:40 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C7A9EA0883 for ; Tue, 6 Nov 2012 05:48:40 -0800 (PST) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from youngberry.canonical.com (youngberry.canonical.com [91.189.89.112]) by gabe.freedesktop.org (Postfix) with ESMTP id 786049E838 for ; Tue, 6 Nov 2012 05:48:30 -0800 (PST) Received: from 5ed48cef.cm-7-5c.dynamic.ziggo.nl ([94.212.140.239] helo=[192.168.1.128]) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1TVjW1-0001gG-9R; Tue, 06 Nov 2012 13:48:29 +0000 Message-ID: <5099152C.1070502@canonical.com> Date: Tue, 06 Nov 2012 14:48:28 +0100 From: Maarten Lankhorst User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121011 Thunderbird/16.0.1 MIME-Version: 1.0 To: Thomas Hellstrom Subject: Re: [PATCH 1/3] drm/ttm: add ttm_bo_is_reserved References: <5078301C.8080200@canonical.com> <5088ED76.7060008@shipmail.org> In-Reply-To: <5088ED76.7060008@shipmail.org> Cc: dri-devel@lists.freedesktop.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+patchwork-dri-devel=patchwork.kernel.org@lists.freedesktop.org Errors-To: dri-devel-bounces+patchwork-dri-devel=patchwork.kernel.org@lists.freedesktop.org Op 25-10-12 09:42, Thomas Hellstrom schreef: > On 10/12/2012 04:58 PM, Maarten Lankhorst wrote: >> Signed-off-by: Maarten Lankhorst >> --- >> drivers/gpu/drm/ttm/ttm_bo.c | 12 ++++++------ >> include/drm/ttm/ttm_bo_api.h | 14 ++++++++++++++ >> 2 files changed, 20 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c >> index be1148e..d9d8541 100644 >> --- a/drivers/gpu/drm/ttm/ttm_bo.c >> +++ b/drivers/gpu/drm/ttm/ttm_bo.c >> @@ -161,9 +161,9 @@ int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, bool interruptible) >> { >> if (interruptible) { >> return wait_event_interruptible(bo->event_queue, >> - atomic_read(&bo->reserved) == 0); >> + !ttm_bo_is_reserved(bo)); >> } else { >> - wait_event(bo->event_queue, atomic_read(&bo->reserved) == 0); >> + wait_event(bo->event_queue, !ttm_bo_is_reserved(bo)); >> return 0; >> } >> } >> @@ -174,7 +174,7 @@ void ttm_bo_add_to_lru(struct ttm_buffer_object *bo) >> struct ttm_bo_device *bdev = bo->bdev; >> struct ttm_mem_type_manager *man; >> - BUG_ON(!atomic_read(&bo->reserved)); >> + BUG_ON(!ttm_bo_is_reserved(bo)); >> if (!(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) { >> @@ -748,7 +748,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible, >> goto out; >> } >> - BUG_ON(!atomic_read(&bo->reserved)); >> + BUG_ON(!ttm_bo_is_reserved(bo)); >> evict_mem = bo->mem; >> evict_mem.mm_node = NULL; >> @@ -1058,7 +1058,7 @@ int ttm_bo_move_buffer(struct ttm_buffer_object *bo, >> struct ttm_mem_reg mem; >> struct ttm_bo_device *bdev = bo->bdev; >> - BUG_ON(!atomic_read(&bo->reserved)); >> + BUG_ON(!ttm_bo_is_reserved(bo)); >> /* >> * FIXME: It's possible to pipeline buffer moves. >> @@ -1115,7 +1115,7 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, >> { >> int ret; >> - BUG_ON(!atomic_read(&bo->reserved)); >> + BUG_ON(!ttm_bo_is_reserved(bo)); >> /* Check that range is valid */ >> if (placement->lpfn || placement->fpfn) >> if (placement->fpfn > placement->lpfn || >> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h >> index 9654451..1d71f6b 100644 >> --- a/include/drm/ttm/ttm_bo_api.h >> +++ b/include/drm/ttm/ttm_bo_api.h >> @@ -705,4 +705,18 @@ extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp, >> extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev); >> +/** >> + * ttm_bo_is_reserved - return an indication if a ttm buffer object is reserved >> + * >> + * @bo: The buffer object to check. >> + * >> + * This function returns an indication if a bo is reserved or not, and should >> + * only be used to print an error when it is not from incorrect api usage, since >> + * there's no guarantee that it is the caller that is holding the reservation. >> + */ >> +static inline bool ttm_bo_is_reserved(struct ttm_buffer_object *bo) >> +{ >> + return atomic_read(&bo->reserved); >> +} >> + >> #endif > This looks good, although for clarity we should add in the comments that > if the caller is holding the reservation, the function is guaranteed to return true. > > Otherwise > Reviewed-by: Thomas Hellstrom Unless you use lockdep, you can't say with 100% certainty if the CALLER is holding it or not. :-) But lockdep can actually check if that's the case with lockdep_is_held(&ttm->reservation_lock); which iterates over all locks held by the current task. ~Maarten Updated version with a comment about return value in ttm_bo_is_reserved: drm/ttm: Add ttm_bo_is_reserved function Signed-off-by: Maarten Lankhorst Reviewed-by: Thomas Hellstrom diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index 2b3f69b..82e2633 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -162,9 +162,9 @@ int ttm_bo_wait_unreserved(struct ttm_buffer_object *bo, bool interruptible) { if (interruptible) { return wait_event_interruptible(bo->event_queue, - atomic_read(&bo->reserved) == 0); + !ttm_bo_is_reserved(bo)); } else { - wait_event(bo->event_queue, atomic_read(&bo->reserved) == 0); + wait_event(bo->event_queue, !ttm_bo_is_reserved(bo)); return 0; } } @@ -175,7 +175,7 @@ void ttm_bo_add_to_lru(struct ttm_buffer_object *bo) struct ttm_bo_device *bdev = bo->bdev; struct ttm_mem_type_manager *man; - BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo)); if (!(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) { @@ -756,7 +756,7 @@ static int ttm_bo_evict(struct ttm_buffer_object *bo, bool interruptible, goto out; } - BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo)); evict_mem = bo->mem; evict_mem.mm_node = NULL; @@ -1063,7 +1063,7 @@ int ttm_bo_move_buffer(struct ttm_buffer_object *bo, struct ttm_mem_reg mem; struct ttm_bo_device *bdev = bo->bdev; - BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo)); /* * FIXME: It's possible to pipeline buffer moves. @@ -1120,7 +1120,7 @@ int ttm_bo_validate(struct ttm_buffer_object *bo, { int ret; - BUG_ON(!atomic_read(&bo->reserved)); + BUG_ON(!ttm_bo_is_reserved(bo)); /* Check that range is valid */ if (placement->lpfn || placement->fpfn) if (placement->fpfn > placement->lpfn || diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index 850424f..7a5b574 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -737,4 +737,20 @@ extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp, extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev); +/** + * ttm_bo_is_reserved - return an indication if a ttm buffer object is reserved + * + * @bo: The buffer object to check. + * + * This function returns an indication if a bo is reserved or not, and should + * only be used to print an error when it is not from incorrect api usage, since + * there's no guarantee that it is the caller that is holding the reservation. + * + * Returns true if reserved, false if unreserved. + */ +static inline bool ttm_bo_is_reserved(struct ttm_buffer_object *bo) +{ + return atomic_read(&bo->reserved); +} + #endif