From patchwork Sat May 18 17:47:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe JAILLET X-Patchwork-Id: 13667682 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4F7A9C25B74 for ; Sat, 18 May 2024 17:47:35 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id BBEAB10E161; Sat, 18 May 2024 17:47:31 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=wanadoo.fr header.i=@wanadoo.fr header.b="Gkmlorq0"; dkim-atps=neutral Received: from smtp.smtpout.orange.fr (smtp-19.smtpout.orange.fr [80.12.242.19]) by gabe.freedesktop.org (Postfix) with ESMTPS id D4FA810E161 for ; Sat, 18 May 2024 17:47:29 +0000 (UTC) Received: from localhost.localdomain ([86.243.17.157]) by smtp.orange.fr with ESMTPA id 8O9WsISRlQOWM8O9Wsvlrw; Sat, 18 May 2024 19:47:28 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=wanadoo.fr; s=t20230301; t=1716054448; bh=UcEQtuE56kOs4tsCCaoGQju/nr916DkGkkvfsJQQWpE=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=Gkmlorq0ugnc3zwFK8MZXPXZN6UPrE4zoMggZlvYunBiE3Ya9e77/9iN42aea/llF i0xDwilOiIdEMFCvThSIkDJZ7QvIjr3McGuJW8B88QtXyrOCZLLarSyueStalElclH ZPGMZd+jIRp9PjU0eKNagNwvQE2vN5fDbpiXZ0vd1IlxWaj0dwmf3kcpb/efD4iFmo YsTFu+Nue9te4ci0k8UX/6yoEpqIg4gNQu5+YYtq7Yy4nawOlBpQ2zGKiKKyWcaXax 7WUoKAeRShDUyHoWYIGECREk+9owyMgEcnQHJ8TOrDEzB46iYIDwhIPDQAcTRjiYCZ ohxtGOqC2C6DQ== X-ME-Helo: localhost.localdomain X-ME-Auth: Y2hyaXN0b3BoZS5qYWlsbGV0QHdhbmFkb28uZnI= X-ME-Date: Sat, 18 May 2024 19:47:28 +0200 X-ME-IP: 86.243.17.157 From: Christophe JAILLET To: Sumit Semwal , Gustavo Padovan , =?utf-8?q?Christian_K=C3=B6nig?= , Kees Cook , "Gustavo A. R. Silva" Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Christophe JAILLET , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-hardening@vger.kernel.org Subject: [PATCH] dma-buf/fence-array: Add flex array to struct dma_fence_array Date: Sat, 18 May 2024 19:47:02 +0200 Message-ID: X-Mailer: git-send-email 2.45.1 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This is an effort to get rid of all multiplications from allocation functions in order to prevent integer overflows [1][2]. The "struct dma_fence_array" can be refactored to add a flex array in order to have the "callback structures allocated behind the array" be more explicit. Do so: - makes the code more readable and safer. - allows using __counted_by() for additional checks - avoids some pointer arithmetic in dma_fence_array_enable_signaling() Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] Link: https://github.com/KSPP/linux/issues/160 [2] Signed-off-by: Christophe JAILLET Reviewed-by: Kees Cook --- Compile tested only. Also, I don't think that 'cb' is a great name and the associated kernel-doc description could certainly be improved. Any proposal welcomed :) --- drivers/dma-buf/dma-fence-array.c | 10 ++++------ include/linux/dma-fence-array.h | 3 +++ 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c index 9b3ce8948351..9c55afaca607 100644 --- a/drivers/dma-buf/dma-fence-array.c +++ b/drivers/dma-buf/dma-fence-array.c @@ -70,7 +70,7 @@ static void dma_fence_array_cb_func(struct dma_fence *f, static bool dma_fence_array_enable_signaling(struct dma_fence *fence) { struct dma_fence_array *array = to_dma_fence_array(fence); - struct dma_fence_array_cb *cb = (void *)(&array[1]); + struct dma_fence_array_cb *cb = array->cb; unsigned i; for (i = 0; i < array->num_fences; ++i) { @@ -168,22 +168,20 @@ struct dma_fence_array *dma_fence_array_create(int num_fences, bool signal_on_any) { struct dma_fence_array *array; - size_t size = sizeof(*array); WARN_ON(!num_fences || !fences); - /* Allocate the callback structures behind the array. */ - size += num_fences * sizeof(struct dma_fence_array_cb); - array = kzalloc(size, GFP_KERNEL); + array = kzalloc(struct_size(array, cb, num_fences), GFP_KERNEL); if (!array) return NULL; + array->num_fences = num_fences; + spin_lock_init(&array->lock); dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock, context, seqno); init_irq_work(&array->work, irq_dma_fence_array_work); - array->num_fences = num_fences; atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences); array->fences = fences; diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h index ec7f25def392..a793f9d5c73b 100644 --- a/include/linux/dma-fence-array.h +++ b/include/linux/dma-fence-array.h @@ -33,6 +33,7 @@ struct dma_fence_array_cb { * @num_pending: fences in the array still pending * @fences: array of the fences * @work: internal irq_work function + * @cb: array of callback helpers */ struct dma_fence_array { struct dma_fence base; @@ -43,6 +44,8 @@ struct dma_fence_array { struct dma_fence **fences; struct irq_work work; + + struct dma_fence_array_cb cb[] __counted_by(num_fences); }; /**