From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751814AbdFGL4G (ORCPT ); Wed, 7 Jun 2017 07:56:06 -0400 Received: from conuserg-10.nifty.com ([210.131.2.77]:43591 "EHLO conuserg-10.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751457AbdFGL4D (ORCPT ); Wed, 7 Jun 2017 07:56:03 -0400 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-10.nifty.com v57BqjZl014276 X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: linux-mtd@lists.infradead.org Cc: Enrico Jorns , Artem Bityutskiy , Dinh Nguyen , Boris Brezillon , Marek Vasut , David Woodhouse , Masami Hiramatsu , Chuanxiao Dong , Jassi Brar , Masahiro Yamada , Russell King , Lars-Peter Clausen , Cyrille Pitchen , linux-kernel@vger.kernel.org, Brian Norris , Richard Weinberger Subject: [PATCH v5 22/23] mtd: nand: denali: use non-managed kmalloc() for DMA buffer Date: Wed, 7 Jun 2017 20:52:31 +0900 Message-Id: <1496836352-8016-23-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1496836352-8016-1-git-send-email-yamada.masahiro@socionext.com> References: <1496836352-8016-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As Russell and Lars stated in the discussion [1], using devm_k*alloc() with DMA is not a good idea. Let's use kmalloc (not kzalloc because no need for zero-out). Also, allocate the buffer as late as possible because it must be freed for any error that follows. [1] https://lkml.org/lkml/2017/3/8/693 Signed-off-by: Masahiro Yamada Cc: Russell King Cc: Lars-Peter Clausen Acked-by: Robin Murphy --- Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: - Newly added drivers/mtd/nand/denali.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c index 963638693850..904f859e19b6 100644 --- a/drivers/mtd/nand/denali.c +++ b/drivers/mtd/nand/denali.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "denali.h" @@ -1386,13 +1387,6 @@ int denali_init(struct denali_nand_info *denali) if (ret) goto disable_irq; - denali->buf = devm_kzalloc(denali->dev, mtd->writesize + mtd->oobsize, - GFP_KERNEL); - if (!denali->buf) { - ret = -ENOMEM; - goto disable_irq; - } - if (ioread32(denali->flash_reg + FEATURES) & FEATURES__DMA) denali->dma_avail = 1; @@ -1477,17 +1471,30 @@ int denali_init(struct denali_nand_info *denali) if (ret) goto disable_irq; + /* + * This buffer is DMA-mapped by denali_{read,write}_page_raw. Do not + * use devm_kmalloc() because the memory allocated by devm_ does not + * guarantee DMA-safe alignment. + */ + denali->buf = kmalloc(mtd->writesize + mtd->oobsize, GFP_KERNEL); + if (!denali->buf) { + ret = -ENOMEM; + goto disable_irq; + } + ret = nand_scan_tail(mtd); if (ret) - goto disable_irq; + goto free_buf; ret = mtd_device_register(mtd, NULL, 0); if (ret) { dev_err(denali->dev, "Failed to register MTD: %d\n", ret); - goto disable_irq; + goto free_buf; } return 0; +free_buf: + kfree(denali->buf); disable_irq: denali_disable_irq(denali); @@ -1501,6 +1508,7 @@ void denali_remove(struct denali_nand_info *denali) struct mtd_info *mtd = nand_to_mtd(&denali->nand); nand_release(mtd); + kfree(denali->buf); denali_disable_irq(denali); } EXPORT_SYMBOL(denali_remove); -- 2.7.4