From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3s3FKj6hlMzDqTq for ; Tue, 2 Aug 2016 09:05:13 +1000 (AEST) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u71N484q136838 for ; Mon, 1 Aug 2016 19:05:12 -0400 Received: from e24smtp01.br.ibm.com (e24smtp01.br.ibm.com [32.104.18.85]) by mx0a-001b2d01.pphosted.com with ESMTP id 24grracqa1-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 01 Aug 2016 19:05:11 -0400 Received: from localhost by e24smtp01.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 1 Aug 2016 20:05:09 -0300 Received: from d24relay01.br.ibm.com (d24relay01.br.ibm.com [9.8.31.16]) by d24dlp01.br.ibm.com (Postfix) with ESMTP id 9EFDA352006E for ; Mon, 1 Aug 2016 19:04:47 -0400 (EDT) Received: from d24av01.br.ibm.com (d24av01.br.ibm.com [9.8.31.91]) by d24relay01.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u71N57sx4059168 for ; Mon, 1 Aug 2016 20:05:07 -0300 Received: from d24av01.br.ibm.com (localhost [127.0.0.1]) by d24av01.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u71N56uW023861 for ; Mon, 1 Aug 2016 20:05:07 -0300 From: Mauricio Faria de Oliveira To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 0/3] dma-mapping, powerpc, nvme: introduce the DMA_ATTR_NO_WARN attribute Date: Mon, 1 Aug 2016 20:05:03 -0300 Message-Id: <1470092706-28075-1-git-send-email-mauricfo@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This patchset introduces dma_attr DMA_ATTR_NO_WARN (just like __GFP_NOWARN), which tells the DMA-mapping subsystem to suppress allocation failure reports. On some architectures allocation failures are reported with error messages to the system logs. Although this can help to identify and debug problems, drivers which handle failures (eg, retry later) have no problems with them, and can actually flood the system logs with error messages that aren't any problem at all, depending on the implementation of the retry mechanism. So, this provides a way for drivers to avoid those error messages on calls where allocation failures are not a problem, and shouldn't bother the logs. - Patch 1/3 introduces the dma_attr DMA_ATTR_NO_WARN. - Patch 2/3 implements support for it on powerpc arch (where this problem was observed; it's possible to extend support for more archs) - Patch 3/3 implements it on the nvme driver (which might repeatedly trip on allocation failures due to high load, flooding system logs with error messages at least on powerpc: "iommu_alloc failed") Changelog: v4: - rebase for commit 53a4b60 dma-mapping: use unsigned long for dma_attrs. - reorder patches 2/3 and 3/3. v3: - nvme: use DMA_ATTR_NO_WARN when ret = BLK_MQ_RQ_QUEUE_BUSY (io will be requeued) but not when ret = BLK_MQ_RQ_QUEUE_ERROR (io will be failed). thanks: Masayoshi Mizuma v2: - all: address warnings from checkpatch.pl (line wrapping and typos) Tested on next-20160801. Mauricio Faria de Oliveira (3): dma-mapping: introduce the DMA_ATTR_NO_WARN attribute powerpc: implement the DMA_ATTR_NO_WARN attribute nvme: use the DMA_ATTR_NO_WARN attribute Documentation/DMA-attributes.txt | 17 +++++++++++++++++ arch/powerpc/kernel/iommu.c | 6 ++++-- drivers/nvme/host/pci.c | 3 ++- include/linux/dma-mapping.h | 5 +++++ 4 files changed, 28 insertions(+), 3 deletions(-) -- 1.8.3.1