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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 C7451C4338F for ; Tue, 10 Aug 2021 06:15:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A0DBD61051 for ; Tue, 10 Aug 2021 06:15:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235510AbhHJGP0 (ORCPT ); Tue, 10 Aug 2021 02:15:26 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:47632 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230243AbhHJGPY (ORCPT ); Tue, 10 Aug 2021 02:15:24 -0400 Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 5FC8F21F68; Tue, 10 Aug 2021 06:15:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1628576102; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=byJ1z/Gp4RuW9kVrXOQ8iDwXnSR4iaNZQ+kO8Ud4vI4=; b=0p7c+DaVluT9AWp7O4B65oRj1auRRRUf8hOPtdRV1RL4uTBEx9u6QsNxl3H2lokE8aBwP6 9BYr3WxXs50Jg5FRHIi5yTwBZD69V8Dofz6U0OryOgR4vFFPOx29EDD0ge21uxJgEC3B1w wQE/eON1K0nEoEK8gRePu32cV6xUnVk= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1628576102; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=byJ1z/Gp4RuW9kVrXOQ8iDwXnSR4iaNZQ+kO8Ud4vI4=; b=l7X2qvVB2EcPwlec0jVvEVey7Icx/4oZGMItf9E/qXSrRkQRfxb6Vx74fLEneaBkI9O0ws ZEXYmZ1LW3xKPqDg== Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id 2391B133D0; Tue, 10 Aug 2021 06:15:02 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id 7DQrB2YZEmFDOgAAGKfGzw (envelope-from ); Tue, 10 Aug 2021 06:15:02 +0000 Subject: Re: [PATCH v5 01/52] core: Introduce the scsi_cmd_to_rq() function To: Bart Van Assche , "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Christoph Hellwig , Ming Lei , "James E.J. Bottomley" References: <20210809230355.8186-1-bvanassche@acm.org> <20210809230355.8186-2-bvanassche@acm.org> From: Hannes Reinecke Message-ID: <6d0dfa0a-1fe6-2a11-2f26-c8aa65079ec7@suse.de> Date: Tue, 10 Aug 2021 08:15:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210809230355.8186-2-bvanassche@acm.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 8/10/21 1:03 AM, Bart Van Assche wrote: > The 'request' member of struct scsi_cmnd is superfluous. The struct > request and struct scsi_cmnd data structures are adjacent and hence the > request pointer can be derived easily from a scsi_cmnd pointer. Introduce > a helper function that performs that conversion in a type-safe way. This > patch is the first step towards removing the request member from struct > scsi_cmnd. Making that change has the following advantages: > - This is a performance optimization since adding an offset to a pointer > takes less time than dereferencing a pointer. > - struct scsi_cmnd becomes smaller. > > Cc: Christoph Hellwig > Cc: Hannes Reinecke > Cc: Ming Lei > Signed-off-by: Bart Van Assche > --- > include/scsi/scsi_cmnd.h | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h > index 90da9617d28a..e76278ea1fee 100644 > --- a/include/scsi/scsi_cmnd.h > +++ b/include/scsi/scsi_cmnd.h > @@ -146,6 +146,12 @@ struct scsi_cmnd { > unsigned int extra_len; /* length of alignment and padding */ > }; > > +/* Variant of blk_mq_rq_from_pdu() that verifies the type of its argument. */ > +static inline struct request *scsi_cmd_to_rq(struct scsi_cmnd *scmd) > +{ > + return blk_mq_rq_from_pdu(scmd); > +} > + > /* > * Return the driver private allocation behind the command. > * Only works if cmd_size is set in the host template. > Reviewed-by: Hannes Reinecke Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer