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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F275C433EF for ; Wed, 8 Jun 2022 21:07:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229957AbiFHVHL (ORCPT ); Wed, 8 Jun 2022 17:07:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45350 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229720AbiFHVHL (ORCPT ); Wed, 8 Jun 2022 17:07:11 -0400 Received: from mail-pg1-f170.google.com (mail-pg1-f170.google.com [209.85.215.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 295A32271A5; Wed, 8 Jun 2022 14:07:09 -0700 (PDT) Received: by mail-pg1-f170.google.com with SMTP id f65so9848086pgc.7; Wed, 08 Jun 2022 14:07:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=9ecb3buQLdnsK4f3qTJQfieUPfKbyWt/zyj1SzIvpTM=; b=GT/cb+ne0jcS2KxL5TzPds92fvJZ70ZbabYgMvnNXbAXohuhQC/fGOVk6sMfwGtNUs +C9UE3wJg8m/rnwID+LXlkyFPHL99M6kZZVx4L8T4AmeWK3JsvYgxerUxBTBUQQ1toTB Zsbk4QZBeuuWvZHTs1sNgrxJZUwUtlfTeBVPJzj5cLMwrqi+8vFzinrc3BCd/E6dYzBv +jFYhOVgcioBAOY2kyq5pQmzwPt906i4cSBI2I276gfR5OUxeleBP2PgatRTU5AWC5Tp Vrb/0/W0jw9FPtv3VzJXccMLG39CYwTO1CpCWWFDwf7ND/W8+pTIqP8Nt77ji1V1UWm0 6Stw== X-Gm-Message-State: AOAM533iN6PH7/ywhyIw1ZauyjPAjFCARqkO2RE8H2gclk9DDIlSurnE PE8bxeId5ZsEf9jGqQdHZeg= X-Google-Smtp-Source: ABdhPJwGJ0nRHde8RTl6xYLYR29tSKmbbRXlGMXSsUmS5fgFGnp4YCile/NXrK4PxwLOOdGqsZyMzw== X-Received: by 2002:a63:18b:0:b0:3fe:e54b:da15 with SMTP id 133-20020a63018b000000b003fee54bda15mr789973pgb.571.1654722428389; Wed, 08 Jun 2022 14:07:08 -0700 (PDT) Received: from ?IPV6:2620:15c:211:201:1cb7:9e5d:5ca4:2a39? ([2620:15c:211:201:1cb7:9e5d:5ca4:2a39]) by smtp.gmail.com with ESMTPSA id t20-20020a170902d29400b00161947ecc82sm15020395plc.199.2022.06.08.14.07.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 08 Jun 2022 14:07:07 -0700 (PDT) Message-ID: Date: Wed, 8 Jun 2022 14:07:05 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits Content-Language: en-US To: John Garry , damien.lemoal@opensource.wdc.com, joro@8bytes.org, will@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, iommu@lists.linux-foundation.org, linux-scsi@vger.kernel.org, liyihang6@hisilicon.com, chenxiang66@hisilicon.com, thunder.leizhen@huawei.com References: <1654507822-168026-1-git-send-email-john.garry@huawei.com> <1654507822-168026-4-git-send-email-john.garry@huawei.com> <31417477-953d-283e-808e-cf8701e820a8@huawei.com> From: Bart Van Assche In-Reply-To: <31417477-953d-283e-808e-cf8701e820a8@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On 6/8/22 10:50, John Garry wrote: > Please note that this limit only applies if we have an IOMMU enabled for > the scsi host dma device. Otherwise we are limited by dma direct or > swiotlb max mapping size, as before. SCSI host bus adapters that support 64-bit DMA may support much larger transfer sizes than 128 KiB. Thanks, Bart.