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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2896DC4338F for ; Fri, 23 Jul 2021 17:26:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E06A60ED7 for ; Fri, 23 Jul 2021 17:26:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231626AbhGWQqW (ORCPT ); Fri, 23 Jul 2021 12:46:22 -0400 Received: from mail-pl1-f172.google.com ([209.85.214.172]:37555 "EHLO mail-pl1-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231171AbhGWQqT (ORCPT ); Fri, 23 Jul 2021 12:46:19 -0400 Received: by mail-pl1-f172.google.com with SMTP id n10so3990476plf.4 for ; Fri, 23 Jul 2021 10:26:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=eIP+gAEGNdJZ8KZlRhJNzrwP+HxVTKEl8qy9jJpz/Y8=; b=mUVqwfFAXnF5Lg0whLF/UJ5vMW0F7xg1JcRPjNsb1b8oiwEdXLigVsZuUHmhLXD99C T/D6EKHU1YPs+be5W1Ok7dLQXB42AV/yoHrqYDxtYYahg/JoBsZ8Ryhm9lLtT942fPko P1SjYKvfCS8XA+FjSRG5INqDUveZiUvj99gGQCzb0uuUioAvGamUdO/Nh2I6yzphbAjh A28MwDo/cX0xDFNyI/YzMzhFlrLsJ5I+t/aHe+2bF3L91X3IlE1oO/FQa5qd8MItR2sx RkyYj3DhJOsLaEb7ZWTAInFzLqMfThgPueKD3DCiK8Mk//QqsfW4NpnZOLjf3v+r+DaU Zxow== X-Gm-Message-State: AOAM533eQvkHvgw8Ow/ZxivLPgSItm/bJqcrLxBr8LPlF8l6Mx83CNyx FVRN0AUmEZGWc6HwacdyXdM= X-Google-Smtp-Source: ABdhPJzFSvdsmTNBbMK1sP98CGL3teU4mJjqQXEpZZpuvjaTewxPkFSJ0Xns15C8cpBJr1f5OWPQtA== X-Received: by 2002:aa7:8509:0:b029:2e5:8cfe:bc17 with SMTP id v9-20020aa785090000b02902e58cfebc17mr5714529pfn.2.1627061212441; Fri, 23 Jul 2021 10:26:52 -0700 (PDT) Received: from garbanzo ([191.96.121.239]) by smtp.gmail.com with ESMTPSA id j13sm9145526pjl.1.2021.07.23.10.26.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Jul 2021 10:26:51 -0700 (PDT) Date: Fri, 23 Jul 2021 10:26:49 -0700 From: Luis Chamberlain To: Anirudh Rayabharam Cc: gregkh@linuxfoundation.org, rafael@kernel.org, skhan@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [PATCH v6 1/2] firmware_loader: use -ETIMEDOUT instead of -EAGAIN in fw_load_sysfs_fallback Message-ID: <20210723172649.t4b2hqlmhk3v7wn5@garbanzo> References: <20210722123229.8731-1-mail@anirudhrb.com> <20210722123229.8731-2-mail@anirudhrb.com> <20210722195924.oezxwv3u3p5k737l@garbanzo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 23, 2021 at 07:28:59PM +0530, Anirudh Rayabharam wrote: > On Thu, Jul 22, 2021 at 12:59:24PM -0700, Luis Chamberlain wrote: > > On Thu, Jul 22, 2021 at 06:02:28PM +0530, Anirudh Rayabharam wrote: > > > The only motivation for using -EAGAIN in commit 0542ad88fbdd81bb > > > ("firmware loader: Fix _request_firmware_load() return val for fw load > > > abort") was to distinguish the error from -ENOMEM, and so there is no > > > real reason in keeping it. Keeping -ETIMEDOU is much telling of what the > > > > Since you'll have to respin, a missing here ^, also add that the > > -ETIMEDOUT is what we'd get when we do time out on the wait, as its > > not clear from the conext being changed. > > > > > reason for a failure is, so just use that. > > > > > > The rest is just trying to document a bit more of the motivations for the > > > error codes, as otherwise we'd lose this information easily. > > > > This is a separate change, and it actually does more than just that. > > Moving code around should be done separately. The idea is to > > first just remove the -EAGAIN so that the change is *easy* to review. > > A remove of a return code *and* a move of code around makes it less > > obvious for code review. And part of the comment is wrong now that we > > removed -EAGAIN. When breaking patches up please review each change > > going into each patch and consider if it makes sense, atomically. > > > > > Suggested-by: Luis Chamberlain > > > Signed-off-by: Anirudh Rayabharam > > > --- > > > drivers/base/firmware_loader/fallback.c | 34 +++++++++++++++++-------- > > > 1 file changed, 24 insertions(+), 10 deletions(-) > > > > > > diff --git a/drivers/base/firmware_loader/fallback.c b/drivers/base/firmware_loader/fallback.c > > > index 91899d185e31..1db94165feaf 100644 > > > --- a/drivers/base/firmware_loader/fallback.c > > > +++ b/drivers/base/firmware_loader/fallback.c > > > @@ -70,7 +70,29 @@ static inline bool fw_sysfs_loading(struct fw_priv *fw_priv) > > > > > > static inline int fw_sysfs_wait_timeout(struct fw_priv *fw_priv, long timeout) > > > { > > > - return __fw_state_wait_common(fw_priv, timeout); > > > + int ret = __fw_state_wait_common(fw_priv, timeout); > > > + > > > + /* > > > + * A signal could be sent to abort a wait. Consider Android's init > > > + * gettting a SIGCHLD, which in turn was the same process issuing the > > > + * sysfs store call for the fallback. In such cases we want to be able > > > + * to tell apart in userspace when a signal caused a failure on the > > > + * wait. In such cases we'd get -ERESTARTSYS. > > > + * > > > + * Likewise though another race can happen and abort the load earlier. > > > > This comment is about the check for fw_load_abort() so since the move is > > not going to happen when you remove -EAGAIN just leave it out. It can be > > added once you do the move. > > > > > + * > > > + * In either case the situation is interrupted so we just inform > > > + * userspace of that and we end things right away. > > > > Be mindful that this is in context of both cases when re-writing the > > patches. > > > > > + * > > > + * When we really time out just tell userspace it should try again, > > > + * perhaps later. > > > > That's the thing, we're getting rid of that -EAGAIN as it made no sense, > > the goal was to just distinguish the error from -ENOMEM. That's it. > > Since we are removing the -EAGAIN, this comment makes no sense as we > > have clarified with Shuah that the goal of her patch was just to > > distinguish the error. > > > > So "tell userspace to try again" makes no sense since if a timeout > > happened userspace can't really try again as we have aborted the whole > > operation to allow firmware to be uploaded. > > > > In fact, please add that to the commit log which removes the -EAGAIN, > > something like: > > > > "Using -EAGAIN is also not correct as this return code is typically used > > to tell userspace to try something again, in this case re-using the > > sysfs loading interface cannot be retried when a timeout happens, so > > the return value is also bogus." > > > > > + */ > > > + if (ret == -ERESTARTSYS || fw_state_is_aborted(fw_priv)) > > > + ret = -EINTR; > > > + else if (fw_priv->is_paged_buf && !fw_priv->data) > > > + ret = -ENOMEM; > > > + > > > + return ret; > > > } > > > > > > struct fw_sysfs { > > > @@ -526,20 +548,12 @@ static int fw_load_sysfs_fallback(struct fw_sysfs *fw_sysfs, long timeout) > > > } > > > > > > retval = fw_sysfs_wait_timeout(fw_priv, timeout); > > > - if (retval < 0 && retval != -ENOENT) { > > > + if (retval < 0) { > > > mutex_lock(&fw_lock); > > > fw_load_abort(fw_sysfs); > > > mutex_unlock(&fw_lock); > > > } > > > > > > - if (fw_state_is_aborted(fw_priv)) { > > > - if (retval == -ERESTARTSYS) > > > - retval = -EINTR; > > > - else > > > - retval = -EAGAIN; > > > > All we want to do is remove this -EAGAIN line in one patch. We > > don't want to move code to another place. We do this to make code > > Is the move necessary or should I drop it from this series entirely? The move is possible, sure. Maybe do that in a separate patch. But just read each patch as you write it, and make sure they do just *one* thing at a time. Re-read the patch once done and make sure each patch makes sense on its own. Luis