From patchwork Sat Jan 9 15:53:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 12008427 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 8E590C433E0 for ; Sat, 9 Jan 2021 15:58:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CA6E238A1 for ; Sat, 9 Jan 2021 15:58:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726267AbhAIP5t (ORCPT ); Sat, 9 Jan 2021 10:57:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726059AbhAIP5s (ORCPT ); Sat, 9 Jan 2021 10:57:48 -0500 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6374EC061786; Sat, 9 Jan 2021 07:57:08 -0800 (PST) Received: by mail-wr1-x430.google.com with SMTP id t30so11920416wrb.0; Sat, 09 Jan 2021 07:57:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=4HHQ9RGvj6Z9FZXDkRGAkIAp92S56tPsxAgDh/4OaCc=; b=u/sYmc5c/Cu8NO4mrleoXIANn1/0yWcpS5qVSuu9Ej40Pg6cIb1W2VHcLIVSdoCM6+ 092goA2x2vIMKwi5Ke5VYmmG1GErTTCvTzbEfpYmZBw4jtkaelBK82s76kGcemq31HOA xfqL7O2GggO3X/Ddxew5rZQWgIubw+JiMPgcApNTL6KGhsV4T6KP0ofhksy5GlO29DSX 3x8b9IwI+DBc3+WIhiMmrbwg3efHOI6dZAB6maG8BDBVlsKpLv9P1C5z6mpef39lCJis 0mv4jFNZirOzb331PwKpD4f0JkL7vaf2PnqQsVwR8hEhsXQFFi6ewCYBqwVzo15sxcHx QYwg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=4HHQ9RGvj6Z9FZXDkRGAkIAp92S56tPsxAgDh/4OaCc=; b=bVbNa+kkp/3isdgMGG1VhEBaK3l9RhX679qN1hq+PmWVXVQW4LVewz8i8oPrwzk1QH sim7m4LovsCBERMWFnqd57AjomJl4NRPr/AeVKqhjs5T+uhhlz9KwvqQe3NX9/xWq7lT IQ3U9vJv2ph506vIpU+9Sx8KmEwsFtjsWQcDcRdIX0+VaFwNnNpeFGIsxlhXmQ2dtyTC hTiy33iQnYV/yD7bULfgGYGnePLJHOMfNvUjrHWcpK6ZmOpdkJQu7MvTMtoe1b2GCW7h mwISWkVyBC9k70L/87NfmX6A5B2p17NwY+iAvnL/w3Rq2hdxVkag39UR0jNRx54brIuA uu7A== X-Gm-Message-State: AOAM532MS4HNYR8bD3unNJ41EGQIgtVCpIYzC6FxQSzBrfQM6obJ3oL+ 3uIYupty3eR4xRA5kYOwVNQ= X-Google-Smtp-Source: ABdhPJzu3MTQCx9PGGHDjGtBcArNIBFP5vEbHEdINlX+Fuik0EPOehbsiOXBuocEkmu9WGSU1L04IA== X-Received: by 2002:a5d:56c3:: with SMTP id m3mr8671869wrw.419.1610207827145; Sat, 09 Jan 2021 07:57:07 -0800 (PST) Received: from localhost.localdomain ([185.69.144.125]) by smtp.gmail.com with ESMTPSA id g78sm15563568wme.33.2021.01.09.07.57.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 09 Jan 2021 07:57:06 -0800 (PST) From: Pavel Begunkov To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] target/file: don't zero iter before iov_iter_bvec Date: Sat, 9 Jan 2021 15:53:27 +0000 Message-Id: <34cd22d6cec046e3adf402accb1453cc255b9042.1610207523.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org iov_iter_bvec() initialises iterators well, no need to pre-zero it beforehand as done in fd_execute_rw_aio(). Compilers can't optimise it out and generate extra code for that (confirmed with assembly). Signed-off-by: Pavel Begunkov Reviewed-by: Bart Van Assche --- drivers/target/target_core_file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c index cce455929778..5a66854def95 100644 --- a/drivers/target/target_core_file.c +++ b/drivers/target/target_core_file.c @@ -267,7 +267,7 @@ fd_execute_rw_aio(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents, struct fd_dev *fd_dev = FD_DEV(dev); struct file *file = fd_dev->fd_file; struct target_core_file_cmd *aio_cmd; - struct iov_iter iter = {}; + struct iov_iter iter; struct scatterlist *sg; ssize_t len = 0; int ret = 0, i;