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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 53837C4CEC7 for ; Thu, 12 Sep 2019 21:45:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F99A208C2 for ; Thu, 12 Sep 2019 21:45:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726780AbfILVpq (ORCPT ); Thu, 12 Sep 2019 17:45:46 -0400 Received: from mail-ot1-f65.google.com ([209.85.210.65]:44668 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725775AbfILVpq (ORCPT ); Thu, 12 Sep 2019 17:45:46 -0400 Received: by mail-ot1-f65.google.com with SMTP id 21so27519625otj.11 for ; Thu, 12 Sep 2019 14:45:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=3rRwpJFwBPUulMQVtfgTqxnlFgmWXlBO+OampqTZSEk=; b=iLniVTVf0XWXkqJOUDUNYRHGKlibMgnbXrlTHCdRTrboTL1Q7O3vrhF2i2Qd2VcmDM 8pjgsm694fr4xb1+pcYwfGbuMOniApvEGbCDkpp+AMypDT10kZaEEsS7wg1z2VO9xjAW TmuKMaT7tLm4+2ZxIX3nwZtMxBRZfEo1twJ9soJncMZZL4c2tco9tzOQR/vqO5lsnogq uflg3vBjjx0imJj0c+AiUVJHW8RM39X3bFl5ySe8gtNNSbtw9CtgmJ7QqJ3+PzDvz4kf Ne0/1rP8cEbjVP5BehoLfEE7RUradgYv2F/CaXMU8EOsIDKsNUzZ52JiGV9k7wHTVQXw APYg== X-Gm-Message-State: APjAAAUfS05+G8v6hrVy5RPkxvvPxgoUMPkZZM226BJpAEiEB30Vby5e wqwTZ/I3fbpD4HcaSbuAVpNOBvHD X-Google-Smtp-Source: APXvYqyCS3wiu/iGVRS4Ag6S1k5Eluti1hRAsaPYJR9/19MVWk9ehXqmkFQ3/YQDwZheSPEqwO9ctw== X-Received: by 2002:a05:6830:1d0:: with SMTP id r16mr34962367ota.143.1568324743459; Thu, 12 Sep 2019 14:45:43 -0700 (PDT) Received: from ?IPv6:2600:1700:65a0:78e0:514:7862:1503:8e4d? ([2600:1700:65a0:78e0:514:7862:1503:8e4d]) by smtp.gmail.com with ESMTPSA id c24sm8978079otd.57.2019.09.12.14.45.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 Sep 2019 14:45:42 -0700 (PDT) Subject: Re: [PATCH v1] IB/iser: Support up to 16MB data transfer in a single command To: Max Gurtovoy , Jason Gunthorpe , Sergey Gorenko Cc: "linux-rdma@vger.kernel.org" References: <20190912103534.18210-1-sergeygo@mellanox.com> <20190912151931.GA15637@mellanox.com> From: Sagi Grimberg Message-ID: <31f80a22-04dc-d144-7bac-940eb8f2b97d@grimberg.me> Date: Thu, 12 Sep 2019 14:45:41 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org >>> Maximum supported IO size is 8MB for the iSER driver. The >>> current value is limited by the ISCSI_ISER_MAX_SG_TABLESIZE >>> macro. But the driver is able to handle 16MB IOs without any >>> significant changes. Increasing this limit can be useful for >>> the storage arrays which are fine tuned for IOs larger than >>> 8 MB. >>> >>> This commit allows to configure maximum IO size up to 16MB >>> using the max_sectors module parameter. >>> >>> Signed-off-by: Sergey Gorenko >>> Reviewed-by: Max Gurtovoy >>> Acked-by: Sagi Grimberg >>> --- >>> Changes from v0: >>> - Change 512 to SECTOR_SIZE (suggested by Sagi) > > is this always true ? 512 == SECTOR_SIZE ? From the documentation it is, and nothing suggest otherwise. /* * The basic unit of block I/O is a sector. It is used in a number of contexts * in Linux (blk, bio, genhd). The size of one sector is 512 = 2**9 * bytes. Variables of type sector_t represent an offset or size that is a * multiple of 512 bytes. Hence these two constants. */ #ifndef SECTOR_SHIFT #define SECTOR_SHIFT 9 #endif #ifndef SECTOR_SIZE #define SECTOR_SIZE (1 << SECTOR_SHIFT) #endif