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=-9.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 DC602C169C4 for ; Fri, 8 Feb 2019 17:34:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7BDE218AC for ; Fri, 8 Feb 2019 17:34:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="W3SaRlV7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727841AbfBHRe5 (ORCPT ); Fri, 8 Feb 2019 12:34:57 -0500 Received: from mail-it1-f193.google.com ([209.85.166.193]:50463 "EHLO mail-it1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727504AbfBHRe4 (ORCPT ); Fri, 8 Feb 2019 12:34:56 -0500 Received: by mail-it1-f193.google.com with SMTP id z7so10746563iti.0 for ; Fri, 08 Feb 2019 09:34:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=7VfEDtG7dKefZTHegCj8nNjKVprjqmLxQfKlQm/1H1o=; b=W3SaRlV7rHby/SnAmVSmMsFangvfNwWZd6mx+1r4POWrH2cEE2mj+4wQX9ToVD2t7E DAc9KkME75Ko1129MgME9F9SzZlw/15383XZViZUD1oC55yDRSnjPzOnP6hmEe2CFJn0 uGtCNGiLsEtrnm8VoDjERDmUwSH2ooP8RffArnRa5Y6XEjQTtoE56vJ1afLdQKwY/kC6 xW0mqIjeGo8niIR5orntk3FRIdc3XKQP4PUnwD7WYYLqXLwFoazjQ8EByQFyFDVSA+kA SHDkT2/HBmgSCVWC+0znHQ9JsYSFkmr3BTckQvjkXvSZdsRQcqiX95rH55eSBS8mAk5H pLrQ== 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:in-reply-to :references; bh=7VfEDtG7dKefZTHegCj8nNjKVprjqmLxQfKlQm/1H1o=; b=sUKETcGUvAZQE/emdYk6NzqYJrcgXv8fDoL5//sQ/Q61N4OfhWNowaEMOCh/EEdcgH Ylfvwk/qR3rf72oELfySwwEjPbok4HkituZ/cG/AbVzDVYinFjmQ9ED2zb7BSP/oPGCZ MCWl7X5F2mME/Mn9a/K4aqb+jjYfYcYLELT3vRSy0XGxVmNdox05uVSngC3ankwRmeHe j9Vbd0KPrwIL9gVhzFt1dR7krTBrzKfai0/rbH/RFxC0BfAa9C/XLbMVAujscTADGT3H IgFNXjxxHjuOSeiiBhDiEbU+MIrnfSg42agHuPeDpjmgrkOh6mDMGrsFeu93p7R3VQNR SIkg== X-Gm-Message-State: AHQUAuZcxmSknCcDpBPuz+70TKLQ7emlPP2duVRI8+w5IcdkmOopTy0L RW0Bo2q73YTuA2g/CnvCoJLELw== X-Google-Smtp-Source: AHgI3IbDJkD5bpLr7ailvJxe0NatQ0RvjOURQJ5dRK2V3rlBFj4qhct/WDSitHsn9tsBjOJh7gPrlA== X-Received: by 2002:a02:9951:: with SMTP id d17mr12059431jak.134.1549647295560; Fri, 08 Feb 2019 09:34:55 -0800 (PST) Received: from localhost.localdomain ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id f142sm1522627itc.15.2019.02.08.09.34.54 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Feb 2019 09:34:54 -0800 (PST) From: Jens Axboe To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk, Jens Axboe Subject: [PATCH 11/19] block: implement bio helper to add iter bvec pages to bio Date: Fri, 8 Feb 2019 10:34:15 -0700 Message-Id: <20190208173423.27014-12-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190208173423.27014-1-axboe@kernel.dk> References: <20190208173423.27014-1-axboe@kernel.dk> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org For an ITER_BVEC, we can just iterate the iov and add the pages to the bio directly. This requires that the caller doesn't releases the pages on IO completion, we add a BIO_NO_PAGE_REF flag for that. The current two callers of bio_iov_iter_get_pages() are updated to check if they need to release pages on completion. This makes them work with bvecs that contain kernel mapped pages already. Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/bio.c | 59 ++++++++++++++++++++++++++++++++------- fs/block_dev.c | 5 ++-- fs/iomap.c | 5 ++-- include/linux/blk_types.h | 1 + 4 files changed, 56 insertions(+), 14 deletions(-) diff --git a/block/bio.c b/block/bio.c index 4db1008309ed..330df572cfb8 100644 --- a/block/bio.c +++ b/block/bio.c @@ -828,6 +828,23 @@ int bio_add_page(struct bio *bio, struct page *page, } EXPORT_SYMBOL(bio_add_page); +static int __bio_iov_bvec_add_pages(struct bio *bio, struct iov_iter *iter) +{ + const struct bio_vec *bv = iter->bvec; + unsigned int len; + size_t size; + + len = min_t(size_t, bv->bv_len, iter->count); + size = bio_add_page(bio, bv->bv_page, len, + bv->bv_offset + iter->iov_offset); + if (size == len) { + iov_iter_advance(iter, size); + return 0; + } + + return -EINVAL; +} + #define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *)) /** @@ -876,23 +893,43 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) } /** - * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio + * bio_iov_iter_get_pages - add user or kernel pages to a bio * @bio: bio to add pages to - * @iter: iov iterator describing the region to be mapped + * @iter: iov iterator describing the region to be added + * + * This takes either an iterator pointing to user memory, or one pointing to + * kernel pages (BVEC iterator). If we're adding user pages, we pin them and + * map them into the kernel. On IO completion, the caller should put those + * pages. If we're adding kernel pages, we just have to add the pages to the + * bio directly. We don't grab an extra reference to those pages (the user + * should already have that), and we don't put the page on IO completion. + * The caller needs to check if the bio is flagged BIO_NO_PAGE_REF on IO + * completion. If it isn't, then pages should be released. * - * Pins pages from *iter and appends them to @bio's bvec array. The - * pages will have to be released using put_page() when done. * The function tries, but does not guarantee, to pin as many pages as - * fit into the bio, or are requested in *iter, whatever is smaller. - * If MM encounters an error pinning the requested pages, it stops. - * Error is returned only if 0 pages could be pinned. + * fit into the bio, or are requested in *iter, whatever is smaller. If + * MM encounters an error pinning the requested pages, it stops. Error + * is returned only if 0 pages could be pinned. */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { + const bool is_bvec = iov_iter_is_bvec(iter); unsigned short orig_vcnt = bio->bi_vcnt; + /* + * If this is a BVEC iter, then the pages are kernel pages. Don't + * release them on IO completion. + */ + if (is_bvec) + bio_set_flag(bio, BIO_NO_PAGE_REF); + do { - int ret = __bio_iov_iter_get_pages(bio, iter); + int ret; + + if (is_bvec) + ret = __bio_iov_bvec_add_pages(bio, iter); + else + ret = __bio_iov_iter_get_pages(bio, iter); if (unlikely(ret)) return bio->bi_vcnt > orig_vcnt ? 0 : ret; @@ -1634,7 +1671,8 @@ static void bio_dirty_fn(struct work_struct *work) next = bio->bi_private; bio_set_pages_dirty(bio); - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_release_pages(bio); bio_put(bio); } } @@ -1650,7 +1688,8 @@ void bio_check_pages_dirty(struct bio *bio) goto defer; } - bio_release_pages(bio); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_release_pages(bio); bio_put(bio); return; defer: diff --git a/fs/block_dev.c b/fs/block_dev.c index 392e2bfb636f..051ab41d1c61 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -338,8 +338,9 @@ static void blkdev_bio_end_io(struct bio *bio) struct bio_vec *bvec; int i; - bio_for_each_segment_all(bvec, bio, i) - put_page(bvec->bv_page); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_for_each_segment_all(bvec, bio, i) + put_page(bvec->bv_page); bio_put(bio); } } diff --git a/fs/iomap.c b/fs/iomap.c index 2ac9eb746d44..9389cf0a1c6f 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -1591,8 +1591,9 @@ static void iomap_dio_bio_end_io(struct bio *bio) struct bio_vec *bvec; int i; - bio_for_each_segment_all(bvec, bio, i) - put_page(bvec->bv_page); + if (!bio_flagged(bio, BIO_NO_PAGE_REF)) + bio_for_each_segment_all(bvec, bio, i) + put_page(bvec->bv_page); bio_put(bio); } } diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index d66bf5f32610..791fee35df88 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -215,6 +215,7 @@ struct bio { /* * bio flags */ +#define BIO_NO_PAGE_REF 0 /* don't put release vec pages */ #define BIO_SEG_VALID 1 /* bi_phys_segments valid */ #define BIO_CLONED 2 /* doesn't own data */ #define BIO_BOUNCED 3 /* bio is a bounce bio */ -- 2.17.1