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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7B191C00140 for ; Mon, 8 Aug 2022 08:12:19 +0000 (UTC) Received: from localhost ([::1]:44556 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oKxs2-0007Ez-Ag for qemu-devel@archiver.kernel.org; Mon, 08 Aug 2022 04:12:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47562) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oKxm6-0004sU-Nm for qemu-devel@nongnu.org; Mon, 08 Aug 2022 04:06:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49768) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oKxlz-00027G-Lc for qemu-devel@nongnu.org; Mon, 08 Aug 2022 04:06:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1659945962; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mDpA2vHu0nz28byx3zvoEi2wc1hgEj9pAzcFwKiYYso=; b=AWMQA2Lwhy2Wc2owtGj7VgvSDyKPdSCq+1DhSQTPYj+xZVR2uQccZprJWcAPAFdKbkBYD+ Ah/Qz+RWlMvNxfVt4lu407ka88opCx0yNgC0jpmSU5MUiRFvdAIXl08YensarswLR5fvR9 e/BSY2xZEmUUeGSJWxzx/4Q22dHQ+fg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-640-JKviJ68jNX-98YJVKbVyvQ-1; Mon, 08 Aug 2022 04:05:58 -0400 X-MC-Unique: JKviJ68jNX-98YJVKbVyvQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6FDE03804062; Mon, 8 Aug 2022 08:05:58 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.194.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8EA8540CF8F2; Mon, 8 Aug 2022 08:05:57 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 4C1D521E6930; Mon, 8 Aug 2022 10:05:56 +0200 (CEST) From: Markus Armbruster To: Nikita Ivanov Cc: qemu-devel@nongnu.org, Peter Maydell , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Christian Schoenebeck , Greg Kurz , Jason Wang , Michael Roth , Konstantin Kostiuk , Paolo Bonzini Subject: Re: [PATCH] error handling: Use TFR() macro where applicable References: <4561100.0A2huPDW8y@silver> Date: Mon, 08 Aug 2022 10:05:56 +0200 In-Reply-To: (Nikita Ivanov's message of "Mon, 8 Aug 2022 10:19:22 +0300") Message-ID: <877d3jupln.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Nikita Ivanov writes: > Summing up the discussion above, I suggest the following patch for TFR() > macro refactoring. (The patch is sequential to the first one I introduced > in the start of the discussion). > >>>From 6318bee052900aa93bba6620b53c7cb2290e5001 Mon Sep 17 00:00:00 2001 > From: Nikita Ivanov > Date: Mon, 8 Aug 2022 09:30:34 +0300 > Subject: [PATCH] Refactoring: rename TFR() to TEMP_FAILURE_RETRY() > > glibc's unistd.h header provides the same macro with the > subtle difference in type casting. Adjust macro name to the > common standard and define conditionally. > > Signed-off-by: Nikita Ivanov > --- > chardev/char-fd.c | 2 +- > chardev/char-pipe.c | 12 +++++++++--- > hw/9pfs/9p-local.c | 6 ++++-- > include/qemu/osdep.h | 6 ++++-- > net/l2tpv3.c | 8 +++++--- > net/tap-linux.c | 2 +- > net/tap.c | 10 ++++++---- > os-posix.c | 2 +- > qga/commands-posix.c | 2 +- > tests/qtest/libqtest.c | 2 +- > util/main-loop.c | 2 +- > util/osdep.c | 2 +- > 12 files changed, 35 insertions(+), 21 deletions(-) > > diff --git a/chardev/char-fd.c b/chardev/char-fd.c > index cf78454841..7f5ed9aba3 100644 > --- a/chardev/char-fd.c > +++ b/chardev/char-fd.c > @@ -198,7 +198,7 @@ int qmp_chardev_open_file_source(char *src, int flags, > Error **errp) > { > int fd = -1; > > - TFR(fd = qemu_open_old(src, flags, 0666)); > + TEMP_FAILURE_RETRY(fd = qemu_open_old(src, flags, 0666)); > if (fd == -1) { > error_setg_file_open(errp, errno, src); > } > diff --git a/chardev/char-pipe.c b/chardev/char-pipe.c > index 66d3b85091..aed97e306b 100644 > --- a/chardev/char-pipe.c > +++ b/chardev/char-pipe.c > @@ -131,8 +131,12 @@ static void qemu_chr_open_pipe(Chardev *chr, > > filename_in = g_strdup_printf("%s.in", filename); > filename_out = g_strdup_printf("%s.out", filename); > - TFR(fd_in = qemu_open_old(filename_in, O_RDWR | O_BINARY)); > - TFR(fd_out = qemu_open_old(filename_out, O_RDWR | O_BINARY)); > + TEMP_FAILURE_RETRY( > + fd_in = qemu_open_old(filename_in, O_RDWR | O_BINARY) > + ); > + TEMP_FAILURE_RETRY( > + fd_out = qemu_open_old(filename_out, O_RDWR | O_BINARY) > + ); Style question: do we want the ");" on its own line? I think we generally don't do that for function and function-like macro calls. > g_free(filename_in); > g_free(filename_out); > if (fd_in < 0 || fd_out < 0) { > @@ -142,7 +146,9 @@ static void qemu_chr_open_pipe(Chardev *chr, > if (fd_out >= 0) { > close(fd_out); > } > - TFR(fd_in = fd_out = qemu_open_old(filename, O_RDWR | O_BINARY)); > + TEMP_FAILURE_RETRY( > + fd_in = fd_out = qemu_open_old(filename, O_RDWR | O_BINARY) > + ); > if (fd_in < 0) { > error_setg_file_open(errp, errno, filename); > return; > diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c > index c90ab947ba..e803c05d0c 100644 > --- a/hw/9pfs/9p-local.c > +++ b/hw/9pfs/9p-local.c > @@ -470,7 +470,7 @@ static ssize_t local_readlink(FsContext *fs_ctx, > V9fsPath *fs_path, > if (fd == -1) { > return -1; > } > - TFR(tsize = read(fd, (void *)buf, bufsz)); > + TEMP_FAILURE_RETRY(tsize = read(fd, (void *)buf, bufsz)); > close_preserve_errno(fd); > } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) || > (fs_ctx->export_flags & V9FS_SM_NONE)) { > @@ -906,7 +906,9 @@ static int local_symlink(FsContext *fs_ctx, const char > *oldpath, > } > /* Write the oldpath (target) to the file. */ > oldpath_size = strlen(oldpath); > - TFR(write_size = write(fd, (void *)oldpath, oldpath_size)); > + TEMP_FAILURE_RETRY( > + write_size = write(fd, (void *)oldpath, oldpath_size) > + ); > close_preserve_errno(fd); > > if (write_size != oldpath_size) { > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > index b1c161c035..55f2927d8b 100644 > --- a/include/qemu/osdep.h > +++ b/include/qemu/osdep.h > @@ -242,8 +242,10 @@ void QEMU_ERROR("code path is reachable") > #if !defined(ESHUTDOWN) > #define ESHUTDOWN 4099 > #endif > - > -#define TFR(expr) do { if ((expr) != -1) break; } while (errno == EINTR) > +#if !defined(TEMP_FAILURE_RETRY) > +#define TEMP_FAILURE_RETRY(expr) \ > + do { if ((expr) != -1) break; } while (errno == EINTR) > +#endif GLibc's version is # define TEMP_FAILURE_RETRY(expression) \ (__extension__ \ ({ long int __result; \ do __result = (long int) (expression); \ while (__result == -1L && errno == EINTR); \ __result; })) The difference isn't just "type casting", it's also statement vs. expression. Is it a good idea to have the macro expand into a statement on some hosts, and into an expression on others? Sure, CI should catch any uses as expression, but delaying compile errors to CI wastes developer time. > > /* time_t may be either 32 or 64 bits depending on the host OS, and > * can be either signed or unsigned, so we can't just hardcode a [...]