From patchwork Thu Oct 29 00:16:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: John Stultz X-Patchwork-Id: 11864235 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 094CB921 for ; Thu, 29 Oct 2020 00:18:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C99AB207E8 for ; Thu, 29 Oct 2020 00:18:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="xJj8RmJe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391005AbgJ2ASC (ORCPT ); Wed, 28 Oct 2020 20:18:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390711AbgJ2AQf (ORCPT ); Wed, 28 Oct 2020 20:16:35 -0400 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FCB0C0613D1 for ; Wed, 28 Oct 2020 17:16:35 -0700 (PDT) Received: by mail-pg1-x542.google.com with SMTP id h6so890085pgk.4 for ; Wed, 28 Oct 2020 17:16:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=32ciZsvjuqlqOY/wfqdLdcPe0LP0hnUNDkBLarWo68s=; b=xJj8RmJeg0BosQBdwbKLMJ+n8cVNNTzx2TIhkn0i3NHPXgR4HVpRD3A6VFz6nAW+dl TN3l8+KQrvPI3kd2nZ/KEEqno4dIwA3eZBS8xHWoyKvClYqCY0Xn9qkWcjDiJ8H+LcWx jkUsAhL2fz8G2TRTlQrYzkuxB++dvl5Bd/FfvdxVGRLD86N+S9WzAbXgF+hDb+Gsn7Mi eV0Mk/0ZyEUflX7OcoXMH32XhDh9dfi5ORoz9zCIokhRE7LgeeEPZneld0ch30YxuvNl v9tYltCh20ylLU2inTijM6EC976Lh2VwJi/w2UemIBzdu23LowdIckp7+X+eL/r5PIos BC6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=32ciZsvjuqlqOY/wfqdLdcPe0LP0hnUNDkBLarWo68s=; b=XDZjI4I/6Edui+vkhp+nXazr4daJDcLFYSLGLj9ktFvjSfswS3zxctJ7xBisZUEUDD 5yU5zFORyEPnOzUNAt6p7Jin221h7ntAlO9wlyG1K5p20j4QThAE+33Zif+MM8GGBVoj jqOeR4hefhH7vCOG5nuW8hymfH8nR+VnXlOnvtlqG145VQWODdrqZzqcLEX9SMCCudJZ CQ5BF9WQL+JfOhiKgFIY1UTcFemj4tBlTOznuf4QGk5y7azu8TEqm3kXGBkajgx0Dv6E VxpdBBPZAEKrhZfCfZrGFgHl/ax8/9+QXPo1LIrC9XeWPQ2h7k+mK74R0KeyDwGGEOZu Tkyw== X-Gm-Message-State: AOAM530Zlbk5DgIx5BlL8m4neuMrsCK1O3OmqquZj8zEwpHaxLwtKMiw VIHub/+HIFeZGrVAAKv1fQBXB7IVbjt5fw== X-Google-Smtp-Source: ABdhPJyh1ISncmk/Stf7Q0lQVjcj36qCB1OP56fIQss+ihQu4WU4/ep0zrPx9Y38G7D+lKrDoLgLsg== X-Received: by 2002:a63:3581:: with SMTP id c123mr1667605pga.233.1603930595101; Wed, 28 Oct 2020 17:16:35 -0700 (PDT) Received: from localhost.localdomain ([2601:1c2:680:1319:692:26ff:feda:3a81]) by smtp.gmail.com with ESMTPSA id u13sm727407pfl.162.2020.10.28.17.16.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Oct 2020 17:16:34 -0700 (PDT) From: John Stultz To: lkml Cc: John Stultz , Sumit Semwal , Liam Mark , Laura Abbott , Brian Starkey , Hridya Valsaraju , Suren Baghdasaryan , Sandeep Patil , Daniel Mentz , Chris Goldsworthy , =?utf-8?q?=C3=98rjan_Eide?= , Robin Murphy , Ezequiel Garcia , Simon Ser , James Jones , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCH v4 4/7] dma-buf: heaps: Skip sync if not mapped Date: Thu, 29 Oct 2020 00:16:21 +0000 Message-Id: <20201029001624.17513-5-john.stultz@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201029001624.17513-1-john.stultz@linaro.org> References: <20201029001624.17513-1-john.stultz@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org This patch is basically a port of Ørjan Eide's similar patch for ION https://lore.kernel.org/lkml/20200414134629.54567-1-orjan.eide@arm.com/ Only sync the sg-list of dma-buf heap attachment when the attachment is actually mapped on the device. dma-bufs may be synced at any time. It can be reached from user space via DMA_BUF_IOCTL_SYNC, so there are no guarantees from callers on when syncs may be attempted, and dma_buf_end_cpu_access() and dma_buf_begin_cpu_access() may not be paired. Since the sg_list's dma_address isn't set up until the buffer is used on the device, and dma_map_sg() is called on it, the dma_address will be NULL if sync is attempted on the dma-buf before it's mapped on a device. Before v5.0 (commit 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code")) this was a problem as the dma-api (at least the swiotlb_dma_ops on arm64) would use the potentially invalid dma_address. How that failed depended on how the device handled physical address 0. If 0 was a valid address to physical ram, that page would get flushed a lot, while the actual pages in the buffer would not get synced correctly. While if 0 is an invalid physical address it may cause a fault and trigger a crash. In v5.0 this was incidentally fixed by commit 55897af63091 ("dma-direct: merge swiotlb_dma_ops into the dma_direct code"), as this moved the dma-api to use the page pointer in the sg_list, and (for Ion buffers at least) this will always be valid if the sg_list exists at all. But, this issue is re-introduced in v5.3 with commit 449fa54d6815 ("dma-direct: correct the physical addr in dma_direct_sync_sg_for_cpu/device") moves the dma-api back to the old behaviour and picks the dma_address that may be invalid. dma-buf core doesn't ensure that the buffer is mapped on the device, and thus have a valid sg_list, before calling the exporter's begin_cpu_access. Logic and commit message originally by: Ørjan Eide Cc: Sumit Semwal Cc: Liam Mark Cc: Laura Abbott Cc: Brian Starkey Cc: Hridya Valsaraju Cc: Suren Baghdasaryan Cc: Sandeep Patil Cc: Daniel Mentz Cc: Chris Goldsworthy Cc: Ørjan Eide Cc: Robin Murphy Cc: Ezequiel Garcia Cc: Simon Ser Cc: James Jones Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Reviewed-by: Brian Starkey Signed-off-by: John Stultz --- drivers/dma-buf/heaps/cma_heap.c | 10 ++++++++++ drivers/dma-buf/heaps/system_heap.c | 10 ++++++++++ 2 files changed, 20 insertions(+) diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index 5341e5e226d5..028f1e8d6041 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -43,6 +43,7 @@ struct dma_heap_attachment { struct device *dev; struct sg_table table; struct list_head list; + bool mapped; }; static int cma_heap_attach(struct dma_buf *dmabuf, @@ -67,6 +68,7 @@ static int cma_heap_attach(struct dma_buf *dmabuf, a->dev = attachment->dev; INIT_LIST_HEAD(&a->list); + a->mapped = false; attachment->priv = a; @@ -101,6 +103,7 @@ static struct sg_table *cma_heap_map_dma_buf(struct dma_buf_attachment *attachme ret = dma_map_sgtable(attachment->dev, table, direction, 0); if (ret) return ERR_PTR(-ENOMEM); + a->mapped = true; return table; } @@ -108,6 +111,9 @@ static void cma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *table, enum dma_data_direction direction) { + struct dma_heap_attachment *a = attachment->priv; + + a->mapped = false; dma_unmap_sgtable(attachment->dev, table, direction, 0); } @@ -122,6 +128,8 @@ static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, mutex_lock(&buffer->lock); list_for_each_entry(a, &buffer->attachments, list) { + if (!a->mapped) + continue; dma_sync_sgtable_for_cpu(a->dev, &a->table, direction); } mutex_unlock(&buffer->lock); @@ -140,6 +148,8 @@ static int cma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, mutex_lock(&buffer->lock); list_for_each_entry(a, &buffer->attachments, list) { + if (!a->mapped) + continue; dma_sync_sgtable_for_device(a->dev, &a->table, direction); } mutex_unlock(&buffer->lock); diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 5c44f9c06807..15b36bc862b1 100644 --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -37,6 +37,7 @@ struct dma_heap_attachment { struct device *dev; struct sg_table *table; struct list_head list; + bool mapped; }; static struct sg_table *dup_sg_table(struct sg_table *table) @@ -84,6 +85,7 @@ static int system_heap_attach(struct dma_buf *dmabuf, a->table = table; a->dev = attachment->dev; INIT_LIST_HEAD(&a->list); + a->mapped = false; attachment->priv = a; @@ -120,6 +122,7 @@ static struct sg_table *system_heap_map_dma_buf(struct dma_buf_attachment *attac if (ret) return ERR_PTR(ret); + a->mapped = true; return table; } @@ -127,6 +130,9 @@ static void system_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *table, enum dma_data_direction direction) { + struct dma_heap_attachment *a = attachment->priv; + + a->mapped = false; dma_unmap_sgtable(attachment->dev, table, direction, 0); } @@ -142,6 +148,8 @@ static int system_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, invalidate_kernel_vmap_range(buffer->vaddr, buffer->len); list_for_each_entry(a, &buffer->attachments, list) { + if (!a->mapped) + continue; dma_sync_sgtable_for_cpu(a->dev, a->table, direction); } mutex_unlock(&buffer->lock); @@ -161,6 +169,8 @@ static int system_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, flush_kernel_vmap_range(buffer->vaddr, buffer->len); list_for_each_entry(a, &buffer->attachments, list) { + if (!a->mapped) + continue; dma_sync_sgtable_for_device(a->dev, a->table, direction); } mutex_unlock(&buffer->lock);