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=-11.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_MED,USER_IN_DEF_DKIM_WL 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 8C659C282CE for ; Wed, 5 Jun 2019 00:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 15E9C2070B for ; Wed, 5 Jun 2019 00:48:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bCfiN04t" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726490AbfFEAsD (ORCPT ); Tue, 4 Jun 2019 20:48:03 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:37034 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726354AbfFEAsD (ORCPT ); Tue, 4 Jun 2019 20:48:03 -0400 Received: by mail-lj1-f193.google.com with SMTP id 131so8969228ljf.4 for ; Tue, 04 Jun 2019 17:48:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=pv23Ci9XYYXbAvdmjUDu6QVKJnotvin7bH7iuxivMig=; b=bCfiN04tgowJLuApBvXwZWyNMtGb9FgYGJp5LkSEcg4PdHWnZmIBeM/cM9k5AbYodp rettTdhr1CO5CzRe80O5GNP151HRdnuXMuXParmN+k4ysLrvJ8T4FJPz5UBNGPIWWhDv jLzSs2o7zt6OpGXykmBbYrEGKSLH0DyvmhFwA2O4C1gJAlb4gCQQYVi8jqNR76aV2CAE B26xYkubYvYF6WWvFMWbUtKHUYW3SWHpux/uSw6Ty7qvZxcnWDlOTriysJ/qSBj39HJL iN8/XK32e67VWiHpnny1O7oiB03Lzd4/CGvnWXT8rNKGMQku64Dn87Rnbdfu/kl1KQN3 xajg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pv23Ci9XYYXbAvdmjUDu6QVKJnotvin7bH7iuxivMig=; b=p0VAdJeoQTNJ6xQSzh3OkHd7XsRUHy5dCYmi+MnlHuxJHSk3eiXc/ZOXyEVrofIXyQ eAX0KxrsPZUkOQiiz2RCdHuN9IVyASWsrM5yn9nFG25f79u/YH2iU3ckU5OOtuXc0dJO ASis3OqXGhfGHPOBucA0yDTa1J7W/ApNm95ljNBLXdO08MBWi4z00ZrsGMVnVsGArEl9 4SFHFXCwOWuhq76MpPwwwNV58OTtoEF3W9nqmBHpfOMIJjljA0IA5wkHFePcFVzSxnpN 5Dc94R9uJgva/8NzLiPIpl+gtmfgWMwuL2v9i8U27i8TRaMzGI1645y11fIHSER6IDKl LrmQ== X-Gm-Message-State: APjAAAVJkQVjfgn74Ilw7upVuSwqSf+YOuC95hRErOv3NK+ZMynEkm+n TLoKcSQ2T/3j3wg0ghjjnG19nIwMXutkpuQe9gPS6Q== X-Google-Smtp-Source: APXvYqxvjJ99N3aai52FzW/2dSKhKjlCCwgFuNgdJiXvkROkaHK9M4UqMQad+SFwjoWlFMwgkqQd/uzHdaUnjHCnq4g= X-Received: by 2002:a2e:a318:: with SMTP id l24mr6685023lje.36.1559695679940; Tue, 04 Jun 2019 17:47:59 -0700 (PDT) MIME-Version: 1.0 References: <20190514221711.248228-1-brendanhiggins@google.com> <20190514221711.248228-5-brendanhiggins@google.com> <20190517175841.F3396216FD@mail.kernel.org> In-Reply-To: <20190517175841.F3396216FD@mail.kernel.org> From: Brendan Higgins Date: Tue, 4 Jun 2019 17:47:48 -0700 Message-ID: Subject: Re: [PATCH v4 04/18] kunit: test: add kunit_stream a std::stream like logger To: Stephen Boyd Cc: Frank Rowand , Greg KH , Josh Poimboeuf , Kees Cook , Kieran Bingham , Luis Chamberlain , Peter Zijlstra , Rob Herring , shuah , "Theodore Ts'o" , Masahiro Yamada , devicetree , dri-devel , kunit-dev@googlegroups.com, "open list:DOCUMENTATION" , linux-fsdevel@vger.kernel.org, linux-kbuild , Linux Kernel Mailing List , "open list:KERNEL SELFTEST FRAMEWORK" , linux-nvdimm , linux-um@lists.infradead.org, Sasha Levin , "Bird, Timothy" , Amir Goldstein , Dan Carpenter , Daniel Vetter , Jeff Dike , Joel Stanley , Julia Lawall , Kevin Hilman , Knut Omang , Logan Gunthorpe , Michael Ellerman , Petr Mladek , Randy Dunlap , Richard Weinberger , David Rientjes , Steven Rostedt , wfg@linux.intel.com Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, May 17, 2019 at 10:58 AM Stephen Boyd wrote: > > Quoting Brendan Higgins (2019-05-14 15:16:57) > > diff --git a/kunit/kunit-stream.c b/kunit/kunit-stream.c > > new file mode 100644 > > index 0000000000000..1884f1b550888 > > --- /dev/null > > +++ b/kunit/kunit-stream.c > > @@ -0,0 +1,152 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * C++ stream style string formatter and printer used in KUnit for outputting > > + * KUnit messages. > > + * > > + * Copyright (C) 2019, Google LLC. > > + * Author: Brendan Higgins > > + */ > > + > > +#include > > +#include > > +#include > > + > > +static const char *kunit_stream_get_level(struct kunit_stream *this) > > +{ > > + unsigned long flags; > > + const char *level; > > + > > + spin_lock_irqsave(&this->lock, flags); > > + level = this->level; > > + spin_unlock_irqrestore(&this->lock, flags); > > + > > + return level; > > Please remove this whole function and inline it to the one call-site. > > > +} > > + > > +void kunit_stream_set_level(struct kunit_stream *this, const char *level) > > +{ > > + unsigned long flags; > > + > > + spin_lock_irqsave(&this->lock, flags); > > + this->level = level; > > + spin_unlock_irqrestore(&this->lock, flags); > > I don't get the locking here. What are we protecting against? Are tests > running in parallel using the same kunit_stream? If so, why is the level > changeable in one call and then adding strings is done in a different > function call? It would make sense to combine the level setting and > string adding so that it's one atomic operation if it's truly a parallel > operation, or remove the locking entirely. I think you are right. I am not sure it makes sense for two separate threads to share a kunit_stream; even if locked properly, it would end up printing out corrupted text. In anycase, I think it makes sense to decide the level when the stream is allocated which would sidestep this issue entirely. > > +} > > + > > +void kunit_stream_add(struct kunit_stream *this, const char *fmt, ...) > > +{ > > + va_list args; > > + struct string_stream *stream = this->internal_stream; > > + > > + va_start(args, fmt); > > + > > + if (string_stream_vadd(stream, fmt, args) < 0) > > + kunit_err(this->test, "Failed to allocate fragment: %s\n", fmt); > > + > > + va_end(args); > > +} > > + > > +void kunit_stream_append(struct kunit_stream *this, > > + struct kunit_stream *other) > > +{ > > + struct string_stream *other_stream = other->internal_stream; > > + const char *other_content; > > + > > + other_content = string_stream_get_string(other_stream); > > + > > + if (!other_content) { > > + kunit_err(this->test, > > + "Failed to get string from second argument for appending.\n"); > > + return; > > + } > > + > > + kunit_stream_add(this, other_content); > > +} > > + > > +void kunit_stream_clear(struct kunit_stream *this) > > +{ > > + string_stream_clear(this->internal_stream); > > +} > > + > > +void kunit_stream_commit(struct kunit_stream *this) > > Should this be rather called kunit_stream_flush()? So the intention is that the string in the buffer will not get printed out until commit is called. In this way, you can build up a message and then decide not to print it. This is useful when you are parsing through a lot of data that would be useful in debugging a failing or broken test, but are not yet sure if it is going to pass or not. I think flush has the connotation, that you are just forcing the buffer to get written out now, but that it will happen regardless eventually, where commit has the correct connotation that you *must* call it in order to write out the data stored in the buffer. Seems as though I should probably add this distinction to the kernel-doc comment. > > +{ > > + struct string_stream *stream = this->internal_stream; > > + struct string_stream_fragment *fragment; > > + const char *level; > > + char *buf; > > + > > + level = kunit_stream_get_level(this); > > + if (!level) { > > + kunit_err(this->test, > > + "Stream was committed without a specified log level.\n"); > > Drop the full-stop? Whoops, nice catch. Will fix in next revision. > > + level = KERN_ERR; > > + kunit_stream_set_level(this, level); > > + } > > + > > + buf = string_stream_get_string(stream); > > + if (!buf) { > > + kunit_err(this->test, > > Can you grow a local variable for 'this->test'? It's used many times. Sure, will fix in next revision. > Also, 'this' is not very kernel idiomatic. We usually name variables by > their type instead of 'this' which is a keyword in other languages. > Perhaps it could be named 'kstream'? Seems reasonable. Will fix in next revision. > > + "Could not allocate buffer, dumping stream:\n"); > > + list_for_each_entry(fragment, &stream->fragments, node) { > > + kunit_err(this->test, fragment->fragment); > > + } > > + kunit_err(this->test, "\n"); > > + goto cleanup; > > + } > > + > > + kunit_printk(level, this->test, buf); > > + kfree(buf); > > + > > +cleanup: > > + kunit_stream_clear(this); > > +} > > + > > +static int kunit_stream_init(struct kunit_resource *res, void *context) > > +{ > > + struct kunit *test = context; > > + struct kunit_stream *stream; > > + > > + stream = kzalloc(sizeof(*stream), GFP_KERNEL); > > Of course, here it's called 'stream', so maybe it should be 'kstream' > here too. Will do. > > > + if (!stream) > > + return -ENOMEM; > > + > > + res->allocation = stream; > > + stream->test = test; > > + spin_lock_init(&stream->lock); > > + stream->internal_stream = new_string_stream(); > > Can new_string_stream() be renamed to alloc_string_stream()? Sorry, I > just see so much C++ isms in here it's hard to read from the kernel > developer perspective. No problem. WIll fix in next revision. > > + > > + if (!stream->internal_stream) { > > Nitpick: Please join this to the "allocation" event above instead of > keeping it separated. Yeah, that's a lot cleaner. Will do. > > + kfree(stream); > > + return -ENOMEM; > > + } > > + > > + return 0; > > +} > > + > > +static void kunit_stream_free(struct kunit_resource *res) > > +{ > > + struct kunit_stream *stream = res->allocation; > > + > > + if (!string_stream_is_empty(stream->internal_stream)) { > > + kunit_err(stream->test, > > + "End of test case reached with uncommitted stream entries.\n"); > > + kunit_stream_commit(stream); > > + } > > + > > + destroy_string_stream(stream->internal_stream); > > + kfree(stream); > > +} > > + > > +struct kunit_stream *kunit_new_stream(struct kunit *test) > > +{ > > + struct kunit_resource *res; > > + > > + res = kunit_alloc_resource(test, > > + kunit_stream_init, > > + kunit_stream_free, > > + test); > > + > > + if (res) > > + return res->allocation; > > + else > > + return NULL; > > Don't have if (...) return ...; else return ..., just return instead of > else. Sorry. Will fix. Thanks!