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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 C9F50C433ED for ; Wed, 7 Apr 2021 12:30:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A0093611C9 for ; Wed, 7 Apr 2021 12:30:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352179AbhDGMbH (ORCPT ); Wed, 7 Apr 2021 08:31:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:49420 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235368AbhDGMbB (ORCPT ); Wed, 7 Apr 2021 08:31:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3AD3460FEE; Wed, 7 Apr 2021 12:30:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617798651; bh=kkWVCkUc0NJVVv2evc8bpyZsUPichPzeLxsPzJH+f4Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=o2V0VZZZHZIPJQ6GHChv3VKyITqB/OqkvnFFKwsBJMHZehszOzM3IjEELsL8s399c bx/GhVQeAVRpN9hiA2DmCiR1LlujuzQ34SbotgdYnn4Af4VO4hWQ5rCA1ibtRgQUbR KlbLETjo/R79EMC/mx7r53fF1UAhPaa2hzXTGg/mUjwnsczqLnjNl0O5iBkCQDTOgb Ax9dXwTUlB6TO9jyNkHLfk4q1kZcm987/SwgjaWTwSQ1eFJWjrnxIIj+Q+kqc9Fp/u 9Od0IsH09WuhqloQrllP7WVC8etG+rn6pfV49evkpshFSbwtBUrlbdoi0ZwwVhPkve MvrjoD9P92RLw== Date: Wed, 7 Apr 2021 15:30:48 +0300 From: Leon Romanovsky To: "ameynarkhede03@gmail.com" Cc: Raphael Norwitz , Alex Williamson , "bhelgaas@google.com ,linux-pci@vger.kernel.org" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI: merge slot and bus reset implementations Message-ID: References: <20210401053656.16065-1-raphael.norwitz@nutanix.com> <20210401105616.71156d08@omen> <20210406081626.31f19c0f@x1.home.shazbot.org> <20210407082356.53subv4np2fx777x@archlinux> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210407082356.53subv4np2fx777x@archlinux> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 07, 2021 at 01:53:56PM +0530, ameynarkhede03@gmail.com wrote: > On 21/04/07 10:23AM, Leon Romanovsky wrote: > > On Tue, Apr 06, 2021 at 08:16:26AM -0600, Alex Williamson wrote: > > > On Sun, 4 Apr 2021 11:04:32 +0300 > > > Leon Romanovsky wrote: > > > > > > > On Thu, Apr 01, 2021 at 10:56:16AM -0600, Alex Williamson wrote: > > > > > On Thu, 1 Apr 2021 15:27:37 +0300 > > > > > Leon Romanovsky wrote: > > > > > > > > > > > On Thu, Apr 01, 2021 at 05:37:16AM +0000, Raphael Norwitz wrote: > > > > > > > Slot resets are bus resets with additional logic to prevent a device > > > > > > > from being removed during the reset. Currently slot and bus resets have > > > > > > > separate implementations in pci.c, complicating higher level logic. As > > > > > > > discussed on the mailing list, they should be combined into a generic > > > > > > > function which performs an SBR. This change adds a function, > > > > > > > pci_reset_bus_function(), which first attempts a slot reset and then > > > > > > > attempts a bus reset if -ENOTTY is returned, such that there is now a > > > > > > > single device agnostic function to perform an SBR. > > > > > > > > > > > > > > This new function is also needed to add SBR reset quirks and therefore > > > > > > > is exposed in pci.h. > > > > > > > > > > > > > > Link: https://lkml.org/lkml/2021/3/23/911 > > > > > > > > > > > > > > Suggested-by: Alex Williamson > > > > > > > Signed-off-by: Amey Narkhede > > > > > > > Signed-off-by: Raphael Norwitz > > > > > > > --- > > > > > > > drivers/pci/pci.c | 17 +++++++++-------- > > > > > > > include/linux/pci.h | 1 + > > > > > > > 2 files changed, 10 insertions(+), 8 deletions(-) > > > > > > > > > > > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > > > > > > index 16a17215f633..12a91af2ade4 100644 > > > > > > > --- a/drivers/pci/pci.c > > > > > > > +++ b/drivers/pci/pci.c > > > > > > > @@ -4982,6 +4982,13 @@ static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe) > > > > > > > return pci_reset_hotplug_slot(dev->slot->hotplug, probe); > > > > > > > } > > > > > > > > > > > > > > +int pci_reset_bus_function(struct pci_dev *dev, int probe) > > > > > > > +{ > > > > > > > + int rc = pci_dev_reset_slot_function(dev, probe); > > > > > > > + > > > > > > > + return (rc == -ENOTTY) ? pci_parent_bus_reset(dev, probe) : rc; > > > > > > > > > > > > The previous coding style is preferable one in the Linux kernel. > > > > > > int rc = pci_dev_reset_slot_function(dev, probe); > > > > > > if (rc != -ENOTTY) > > > > > > return rc; > > > > > > return pci_parent_bus_reset(dev, probe); > > > > > > > > > > > > > > > That'd be news to me, do you have a reference? I've never seen > > > > > complaints for ternaries previously. Thanks, > > > > > > > > The complaint is not to ternaries, but to the function call as one of > > > > the parameters, that makes it harder to read. > > > > > > Sorry, I don't find a function call as a parameter to a ternary to be > > > extraordinary, nor do I find it to be a discouraged usage model within > > > the kernel. This seems like a pretty low bar for hard to read code. > > > > It is up to us where this bar is set. > > > > Thanks > On the side note there are plenty of places where this pattern is used > though > for example - > kernel/time/clockevents.c:328: > return force ? clockevents_program_min_delta(dev) : -ETIME; > > kernel/trace/trace_kprobe.c:233: > return tk ? within_error_injection_list(trace_kprobe_address(tk)) : > false; > > kernel/signal.c:3104: > return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0; > etc Did you look when they were introduced? Thanks > > Thanks, > Amey