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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 6DB72C4724C for ; Fri, 1 May 2020 17:49:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46BB220857 for ; Fri, 1 May 2020 17:49:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="Nu25g7pI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729927AbgEARtM (ORCPT ); Fri, 1 May 2020 13:49:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729776AbgEARtL (ORCPT ); Fri, 1 May 2020 13:49:11 -0400 Received: from mail-il1-x143.google.com (mail-il1-x143.google.com [IPv6:2607:f8b0:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40296C061A0C for ; Fri, 1 May 2020 10:49:11 -0700 (PDT) Received: by mail-il1-x143.google.com with SMTP id b18so5155821ilf.2 for ; Fri, 01 May 2020 10:49:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=FAkF2yaKZTirBIt4k8vbrMCWa7L6IDgN4q10kaek3iU=; b=Nu25g7pInQqg92NCuHrYmayuvi3zj47l19mKYK+v6nZ4geQuwZmiJFA0Ii0QRLaf2k xhcszlyfj33HWh3Xi5E56xHj2YdoWvAna+nzO5duPolVZHd5AwqU1VwJvEYWiKV5tNrZ VVgz6Z8ZDZ1dlDXalq4Xzu5DlrcSogG11QqcmPgyBYcPsqY6QlxwCN7+yTLiZ4xKCo7Z 5wN4N3ChX/WfdltfWQ01AVZeB/vbq6zulX6fFL5caZZSbqoWdenu5DmZNr0JSsR6zNnz 7S4JvLkRqEBK1s7dysopowoExTk3x8svJXpsW2HZgqPm4pLLRFkJUqVbqHncgDwv96sp 7gbQ== 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=FAkF2yaKZTirBIt4k8vbrMCWa7L6IDgN4q10kaek3iU=; b=Q7fC6263ouwNFgHdb7C3B2iiSCOmPRhiwcfbsrZfyYLQhz9NcVbwMhV9VcoxdgCwsh 1darm8Yl7zaJzQ5TsTU2njTGx/IPAwx/wJmRyD1I0QN1oUGJObWh/BV+ISkJyACfvUC2 NJAnpiEX1TWfcgEoT2rc/os4VLz5yhG61CszfGZD5Y2ixMMSyHK3kaLHVyEG5sVTRAhp hQymu0spBTIbz+eCNsvC1q4zW1nFV5uJukW7sZDJ3t7aMbQXJxPXfm5teH03D0kS2p7E oh2uXD9jWpV5AiICaVxwrYc+79ZvZmSIlz2Y7fr65BbZ4ExNS0hiEJJqrux6N054TSBD bZKw== X-Gm-Message-State: AGi0PuZjI+/bWqlxXi1AFzEkU3hmfNqaaOsh/Gsf435SOJWLA7l3NvBm LUAxYMpdxazS3v4f7V9uDa7SdcJ6iZfqjw== X-Google-Smtp-Source: APiQypIjzlOj0z/RyQ2dh1il3B4WXx3fOLCltjGmV8lOFrB8LH4cwP0bYXdcjZVDSR+f+bbE+SWviQ== X-Received: by 2002:a92:4952:: with SMTP id w79mr4374379ila.15.1588355349738; Fri, 01 May 2020 10:49:09 -0700 (PDT) Received: from [192.168.1.159] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id d23sm1130687ioc.48.2020.05.01.10.49.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 01 May 2020 10:49:08 -0700 (PDT) Subject: Re: [PATCH v2] eventfd: convert to f_op->read_iter() To: Al Viro Cc: linux-fsdevel , "linux-kernel@vger.kernel.org" References: <20200501174306.GM23230@ZenIV.linux.org.uk> From: Jens Axboe Message-ID: <2fa3e8dc-172e-2ac6-bc5e-a8fea5491e22@kernel.dk> Date: Fri, 1 May 2020 11:49:07 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200501174306.GM23230@ZenIV.linux.org.uk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/1/20 11:43 AM, Al Viro wrote: > On Fri, May 01, 2020 at 11:18:05AM -0600, Jens Axboe wrote: > >> - if (res > 0 && put_user(ucnt, (__u64 __user *)buf)) >> + if (res > 0 && copy_to_iter(&ucnt, res, iov) < res) > > *whoa* > > It is correct, but only because here res > 0 <=> res == 8. > And that's not trivial at the first glance. > > Please, turn that into something like Looks good to me, just one minor edit: > if (iov_iter_count(to) < sizeof(ucnt)) > return -EINVAL; > spin_lock_irq(&ctx->wqh.lock); > if (!ctx->count) { > if (unlikely(file->f_flags & O_NONBLOCK) { > spin_unlock_irq(&ctx->wqh.lock) > return -EAGAIN; > } > __add_wait_queue(&ctx->wqh, &wait); > for (;;) { > set_current_state(TASK_INTERRUPTIBLE); > if (ctx->count) > break; > if (signal_pending(current)) { > spin_unlock_irq(&ctx->wqh.lock) > return -ERESTARTSYS; > } We need to remove waitq and re-set task state here. I'll run a sanity check on that and send out a v3. -- Jens Axboe