From patchwork Tue Apr 14 07:42:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11486951 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4F27C912 for ; Tue, 14 Apr 2020 07:43:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 360882137B for ; Tue, 14 Apr 2020 07:43:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nD1jFWNX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406816AbgDNHmm (ORCPT ); Tue, 14 Apr 2020 03:42:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406809AbgDNHmj (ORCPT ); Tue, 14 Apr 2020 03:42:39 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07BD2C008748; Tue, 14 Apr 2020 00:42:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=Ual/dMzALNy8sA75wgtQ+6CUGk8C9/Ruhu//u9rXiYs=; b=nD1jFWNXBCPAHbKCVLUh/4zZP6 aMmoAa2p2OsI8xgMcnB2Cn2pKZLtc9sWDwBKzIOUkA23FTslj2T/Be9JdJ4HQVKaEyXHHQMuW+sfu jn6zfc5VOaCWrYlqGOs25hrYbadm7LCeLtoppuaGtok7dBPU2ONjPtVyzQQ9wf4TGJHdhA/9vW2UH 3mLC9RoxUAmaa7Wl/cGJ3jRcIBTrEgaioW3BYA3yXv+djI+7ET76a/vdqROV+H0pVYi8BtA03QTja t8b2rWol0S9WjASVxYfn4Xp9JPF6Qg6Lmv60JIRaPq3EqVTeORW/hap4olwjWqc3pzDjOmLNF2ghk oy8BDYBA==; Received: from [2001:4bb8:180:384b:4c21:af7:dd95:e552] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOGDJ-00078L-FJ; Tue, 14 Apr 2020 07:42:33 +0000 From: Christoph Hellwig To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org Subject: [PATCH 2/5] block: provide a blk_rq_map_sg variant that returns the last element Date: Tue, 14 Apr 2020 09:42:22 +0200 Message-Id: <20200414074225.332324-3-hch@lst.de> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200414074225.332324-1-hch@lst.de> References: <20200414074225.332324-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org To be able to move some of the special purpose hacks in blk_rq_map_sg into the callers we need a variant that returns the last mapped S/G list element to the caller. Add that variant as __blk_rq_map_sg and make blk_rq_map_sg a trivial inline wrapper around it. Signed-off-by: Christoph Hellwig --- block/blk-merge.c | 25 ++++++++++++------------- include/linux/blkdev.h | 10 +++++++++- 2 files changed, 21 insertions(+), 14 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 99c9759f3a8a..ee618cdb141e 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -519,24 +519,23 @@ static int __blk_bios_map_sg(struct request_queue *q, struct bio *bio, * map a request to scatterlist, return number of sg entries setup. Caller * must make sure sg can hold rq->nr_phys_segments entries */ -int blk_rq_map_sg(struct request_queue *q, struct request *rq, - struct scatterlist *sglist) +int __blk_rq_map_sg(struct request_queue *q, struct request *rq, + struct scatterlist *sglist, struct scatterlist **last_sg) { - struct scatterlist *sg = NULL; int nsegs = 0; if (rq->rq_flags & RQF_SPECIAL_PAYLOAD) - nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, &sg); + nsegs = __blk_bvec_map_sg(rq->special_vec, sglist, last_sg); else if (rq->bio && bio_op(rq->bio) == REQ_OP_WRITE_SAME) - nsegs = __blk_bvec_map_sg(bio_iovec(rq->bio), sglist, &sg); + nsegs = __blk_bvec_map_sg(bio_iovec(rq->bio), sglist, last_sg); else if (rq->bio) - nsegs = __blk_bios_map_sg(q, rq->bio, sglist, &sg); + nsegs = __blk_bios_map_sg(q, rq->bio, sglist, last_sg); if (blk_rq_bytes(rq) && (blk_rq_bytes(rq) & q->dma_pad_mask)) { unsigned int pad_len = (q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; - sg->length += pad_len; + (*last_sg)->length += pad_len; rq->extra_len += pad_len; } @@ -544,9 +543,9 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, if (op_is_write(req_op(rq))) memset(q->dma_drain_buffer, 0, q->dma_drain_size); - sg_unmark_end(sg); - sg = sg_next(sg); - sg_set_page(sg, virt_to_page(q->dma_drain_buffer), + sg_unmark_end(*last_sg); + *last_sg = sg_next(*last_sg); + sg_set_page(*last_sg, virt_to_page(q->dma_drain_buffer), q->dma_drain_size, ((unsigned long)q->dma_drain_buffer) & (PAGE_SIZE - 1)); @@ -554,8 +553,8 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, rq->extra_len += q->dma_drain_size; } - if (sg) - sg_mark_end(sg); + if (*last_sg) + sg_mark_end(*last_sg); /* * Something must have been wrong if the figured number of @@ -565,7 +564,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, return nsegs; } -EXPORT_SYMBOL(blk_rq_map_sg); +EXPORT_SYMBOL(__blk_rq_map_sg); static inline int ll_new_hw_segment(struct request *req, struct bio *bio, unsigned int nr_phys_segs) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 76da162b6ae9..496dc9491026 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1136,7 +1136,15 @@ static inline unsigned short blk_rq_nr_discard_segments(struct request *rq) return max_t(unsigned short, rq->nr_phys_segments, 1); } -extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); +int __blk_rq_map_sg(struct request_queue *q, struct request *rq, + struct scatterlist *sglist, struct scatterlist **last_sg); +static inline int blk_rq_map_sg(struct request_queue *q, struct request *rq, + struct scatterlist *sglist) +{ + struct scatterlist *last_sg = NULL; + + return __blk_rq_map_sg(q, rq, sglist, &last_sg); +} extern void blk_dump_rq_flags(struct request *, char *); extern long nr_blockdev_pages(void);