From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] mmc: core: Lower max_seg_size if too high for DMA Date: Thu, 29 Nov 2018 11:13:32 -0800 Message-ID: <20181129191332.GY53235@atomide.com> References: <20181031155738.18367-1-tony@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Ulf Hansson Cc: "linux-mmc@vger.kernel.org" , Kishon Vijay Abraham I , Peter Ujfalusi , Russell King , linux-omap , Linux ARM List-Id: linux-mmc@vger.kernel.org * Ulf Hansson [181119 12:09]: > On 31 October 2018 at 16:57, Tony Lindgren wrote: > > With CONFIG_DMA_API_DEBUG_SG a device may produce the following warning: > > > > "DMA-API: mapping sg segment longer than device claims to support" > > > > We default to 64KiB if a DMA engine driver does not initialize dma_parms > > and call dma_set_max_seg_size(). This may be lower that what many MMC > > drivers do with mmc->max_seg_size = mmc->max_blk_size * mmc->max_blk_count. > > > > Let's do a sanity check for max_seg_size being higher than what DMA > > supports in mmc_add_host() and lower it as needed. > > > > Cc: Kishon Vijay Abraham I > > Cc: Peter Ujfalusi > > Cc: Russell King > > Reported-by: Russell King > > Signed-off-by: Tony Lindgren > > --- > > drivers/mmc/core/host.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c > > --- a/drivers/mmc/core/host.c > > +++ b/drivers/mmc/core/host.c > > @@ -13,6 +13,7 @@ > > */ > > > > #include > > +#include > > #include > > #include > > #include > > @@ -415,6 +416,19 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) > > > > EXPORT_SYMBOL(mmc_alloc_host); > > > > +static void mmc_check_max_seg_size(struct mmc_host *host) > > +{ > > + unsigned int max_seg_size = dma_get_max_seg_size(mmc_dev(host)); > > Is dma_get_max_seg_size() really intended to be called for any struct > device (representing the mmc controller) like this? > > My understanding is that the dma_get_max_seg_size() is supposed to be > called by using the DMA engine device, no? Oh good catch sounds like I'm calling it for the wrong device, need to check. In that case sounds like this can't be generic? Regards, Tony From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55F06C43441 for ; Thu, 29 Nov 2018 19:16:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1CDB621104 for ; Thu, 29 Nov 2018 19:16:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="VvweK3et" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1CDB621104 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=atomide.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=dvI6Ro9IjmlUUTtxehf2QGNIOSVxQHjdOWB0StWkKLk=; b=VvweK3etU1I2rw xmecsVfGiYypuqwPMzDnSmCrQSxZXb+4vGUJgV8CVwb698b5JvqWiuFWo99V+Y2BzURm7quO+x5gg 1s5+7xWK8pZ/4DP5bv/s5bqnW07Pjs6VegVxtJjllmfBte/s1Vr0HBVogWL0tXbhQSMMp0rLDLlKe rCgqZSmNKJ4fS+X6S6xOIvICWV+tI+LaYTGhXgYmHdm0Xm52EAZVC8bsNS99EVjzPUGtWs09mpyFI NVjJN0raQH3/W3Xl/zaUe3byk34RCicVqYYAvcSmA+Bo4mYeWon9cHHzk9CENtvc6CVso9s4EQXaY W6wImbI/Lg7A4ebzkRuw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gSRn8-0007Nf-Jh; Thu, 29 Nov 2018 19:16:02 +0000 Received: from muru.com ([72.249.23.125]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gSRkw-0003gb-46 for linux-arm-kernel@lists.infradead.org; Thu, 29 Nov 2018 19:13:53 +0000 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 6791D80EA; Thu, 29 Nov 2018 19:13:37 +0000 (UTC) Date: Thu, 29 Nov 2018 11:13:32 -0800 From: Tony Lindgren To: Ulf Hansson Subject: Re: [PATCH] mmc: core: Lower max_seg_size if too high for DMA Message-ID: <20181129191332.GY53235@atomide.com> References: <20181031155738.18367-1-tony@atomide.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181129_111347_002659_FD1DEA7B X-CRM114-Status: GOOD ( 18.38 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "linux-mmc@vger.kernel.org" , Kishon Vijay Abraham I , Peter Ujfalusi , Russell King , linux-omap , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org * Ulf Hansson [181119 12:09]: > On 31 October 2018 at 16:57, Tony Lindgren wrote: > > With CONFIG_DMA_API_DEBUG_SG a device may produce the following warning: > > > > "DMA-API: mapping sg segment longer than device claims to support" > > > > We default to 64KiB if a DMA engine driver does not initialize dma_parms > > and call dma_set_max_seg_size(). This may be lower that what many MMC > > drivers do with mmc->max_seg_size = mmc->max_blk_size * mmc->max_blk_count. > > > > Let's do a sanity check for max_seg_size being higher than what DMA > > supports in mmc_add_host() and lower it as needed. > > > > Cc: Kishon Vijay Abraham I > > Cc: Peter Ujfalusi > > Cc: Russell King > > Reported-by: Russell King > > Signed-off-by: Tony Lindgren > > --- > > drivers/mmc/core/host.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c > > --- a/drivers/mmc/core/host.c > > +++ b/drivers/mmc/core/host.c > > @@ -13,6 +13,7 @@ > > */ > > > > #include > > +#include > > #include > > #include > > #include > > @@ -415,6 +416,19 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) > > > > EXPORT_SYMBOL(mmc_alloc_host); > > > > +static void mmc_check_max_seg_size(struct mmc_host *host) > > +{ > > + unsigned int max_seg_size = dma_get_max_seg_size(mmc_dev(host)); > > Is dma_get_max_seg_size() really intended to be called for any struct > device (representing the mmc controller) like this? > > My understanding is that the dma_get_max_seg_size() is supposed to be > called by using the DMA engine device, no? Oh good catch sounds like I'm calling it for the wrong device, need to check. In that case sounds like this can't be generic? Regards, Tony _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel