From patchwork Wed Jan 11 14:27:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13096807 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5EC84C5479D for ; Wed, 11 Jan 2023 14:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238996AbjAKOcE (ORCPT ); Wed, 11 Jan 2023 09:32:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238563AbjAKObm (ORCPT ); Wed, 11 Jan 2023 09:31:42 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1220A37530 for ; Wed, 11 Jan 2023 06:27:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673447263; 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: content-transfer-encoding:content-transfer-encoding; bh=Encmrg/Q4pn4U4TaedIzlRttIsiQ9mtGF2IR0CVdSuk=; b=Ge0jJUV+wWT5y4MH4ONcnbmSul5rUe4Rzp5y8P3ipTWuPCT26HordYOr+CNCqbdc+raNX9 qn6Bw63c7Cf8KFpmY/+ILY8zxJT5mD+MCbxoF8kFHf8pYdJsPZWeuDSxO6oCGlu/lV3GMC rF2vxuuAdK+ouiHr2Eo//850zV9XAUs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-661-lPtvx7LnPke_XH7ONluRdw-1; Wed, 11 Jan 2023 09:27:39 -0500 X-MC-Unique: lPtvx7LnPke_XH7ONluRdw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id F1301857D0D; Wed, 11 Jan 2023 14:27:38 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.87]) by smtp.corp.redhat.com (Postfix) with ESMTP id B0D39492C14; Wed, 11 Jan 2023 14:27:35 +0000 (UTC) Subject: [PATCH v5 0/9] iov_iter: Add extraction helpers From: David Howells To: Al Viro Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Rohith Surabattula , linux-block@vger.kernel.org, Matthew Wilcox , Jeff Layton , linux-cachefs@redhat.com, Jan Kara , Logan Gunthorpe , Christoph Hellwig , Jens Axboe , Steve French , Shyam Prasad N , John Hubbard , linux-cifs@vger.kernel.org, dhowells@redhat.com, Christoph Hellwig , Matthew Wilcox , Jens Axboe , Jan Kara , Jeff Layton , Logan Gunthorpe , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 11 Jan 2023 14:27:35 +0000 Message-ID: <167344725490.2425628.13771289553670112965.stgit@warthog.procyon.org.uk> User-Agent: StGit/1.5 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Hi Al, Here are patches clean up some use of READ/WRITE and ITER_SOURCE/DEST, patches to provide support for extracting pages from an iov_iter and a patch to use the primary extraction function in the block layer bio code if you could take a look? [!] NOTE that I've switched the functions to be exported GPL-only at Christoph's request[1]. They are, however, intended as a replacement for iov_iter_get_pages*(), which is not marked _GPL - so that functionality will probably become unavailable to non-GPL 3rd party modules in future. The first three patches deal with ITER_SOURCE/DEST: (1) Switch ITER_SOURCE/DEST to an enum and add a couple of helper functions to query if an iterator represents a source or a destination buffer. Using an enum may allow extra consistency warnings from the compiler. (2) Use the ITER_SOURCE/DEST values in the iov_iter core functions rather than READ/WRITE. (3) Get rid of most of the callers of iov_iter_rw(), using the IOCB_WRITE and IOMAP_WRITE instead where available. This leaves only two places looking at the this value: a consistency check in cifs and a single place in the block layer. The next patch adds a replacement for iov_iter_get_pages*(), including Logan's new version: (4) Add a function to list-only, get or pin pages from an iterator as a future replacement for iov_iter_get_pages*(). Pointers to the pages are placed into an array (which will get allocated if not provided) and, depending on the iterator type and direction, the pages will have a ref or a pin get on them or be left untouched (on the assumption that the caller manages their lifetime). The determination is: UBUF/IOVEC + DEST -> pin UBUF/IOVEC + SOURCE -> get PIPE + DEST -> list-only BVEC/XARRAY -> list-only Anything else -> EFAULT The function also returns an indication of which of "list only, get or pin" the extraction function did to aid in cleaning up (returning 0, FOLL_GET or FOLL_PIN as appropriate). Then there are a couple of patches that add stuff to netfslib that I want to use there as well as in cifs: (5) Add a netfslib function to use (4) to extract pages from an ITER_IOBUF or ITER_UBUF iterator into an ITER_BVEC iterator. This will get or pin the pages as appropriate. (6) Add a netfslib function to extract pages from an iterator that's of type ITER_UBUF/IOVEC/BVEC/KVEC/XARRAY and add them to a scatterlist. The function in (4) is used for a UBUF and IOVEC iterators, so those need cleaning up afterwards. BVEC and XARRAY iterators are ungot and unpinned and may be rendered into elements that span multiple pages, for example if large folios are present. Finally, there are a set of three patches to make the block layer's BIO code use iov_iter_extract_pages(): (7) Replace BIO_NO_PAGE_REF with BIO_PAGE_REFFED (opposite logic). (8) Make the block layer's BIO code pin pages or leave pages unaltered rather than getting a ref on the pages when the circumstances warrant, and noting in the bio struct what cleanups should be performed so that the bio cleanup code then does the right thing. (9) Remove an unnecessary check against 0 in bio_flagged() (it returns bool) thus allowing the gcc optimiser to combine multiple instances of the bitwise-AND on the same flags value. Changes: ======== ver #5) - Replace BIO_NO_PAGE_REF with BIO_PAGE_REFFED and split into own patch. - Transcribe FOLL_GET/PIN into BIO_PAGE_REFFED/PINNED flags. - Add patch to allow bio_flagged() to be combined by gcc. ver #4) - Drop the patch to move the FOLL_* flags to linux/mm_types.h as they're no longer referenced by linux/uio.h. - Add ITER_SOURCE/DEST cleanup patches. - Make iov_iter/netfslib iter extraction patches use ITER_SOURCE/DEST. - Allow additional gup_flags to be passed into iov_iter_extract_pages(). - Add struct bio patch. ver #3) - Switch to using EXPORT_SYMBOL_GPL to prevent indirect 3rd-party access to get/pin_user_pages_fast()[1]. ver #2) - Rolled the extraction cleanup mode query function into the extraction function, returning the indication through the argument list. - Fixed patch 4 (extract to scatterlist) to actually use the new extraction API. I've pushed the patches here also: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=iov-extract David Link: https://lore.kernel.org/r/Y3zFzdWnWlEJ8X8/@infradead.org/ [1] Link: https://lore.kernel.org/r/166697254399.61150.1256557652599252121.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/166722777223.2555743.162508599131141451.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/166732024173.3186319.18204305072070871546.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/166869687556.3723671.10061142538708346995.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/166920902005.1461876.2786264600108839814.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/166997419665.9475.15014699817597102032.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/167305160937.1521586.133299343565358971.stgit@warthog.procyon.org.uk/ # v4 --- David Howells (9): iov_iter: Change the direction macros into an enum iov_iter: Use the direction in the iterator functions iov_iter: Use IOCB/IOMAP_WRITE if available rather than iterator direction iov_iter: Add a function to extract a page list from an iterator netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator netfs: Add a function to extract an iterator into a scatterlist bio: Rename BIO_NO_PAGE_REF to BIO_PAGE_REFFED and invert the meaning iov_iter, block: Make bio structs pin pages rather than ref'ing if appropriate bio: Fix bio_flagged() so that it can be combined block/bio.c | 59 ++++-- block/fops.c | 8 +- fs/9p/vfs_addr.c | 2 +- fs/affs/file.c | 4 +- fs/ceph/file.c | 2 +- fs/dax.c | 6 +- fs/direct-io.c | 22 +-- fs/exfat/inode.c | 6 +- fs/ext2/inode.c | 2 +- fs/f2fs/file.c | 10 +- fs/fat/inode.c | 4 +- fs/fuse/dax.c | 2 +- fs/fuse/file.c | 8 +- fs/hfs/inode.c | 2 +- fs/hfsplus/inode.c | 2 +- fs/iomap/direct-io.c | 6 +- fs/jfs/inode.c | 2 +- fs/netfs/Makefile | 1 + fs/netfs/iterator.c | 367 ++++++++++++++++++++++++++++++++++ fs/nfs/direct.c | 2 +- fs/nilfs2/inode.c | 2 +- fs/ntfs3/inode.c | 2 +- fs/ocfs2/aops.c | 2 +- fs/orangefs/inode.c | 2 +- fs/reiserfs/inode.c | 2 +- fs/udf/inode.c | 2 +- include/linux/bio.h | 5 +- include/linux/blk_types.h | 3 +- include/linux/netfs.h | 7 + include/linux/uio.h | 59 ++++-- lib/iov_iter.c | 407 +++++++++++++++++++++++++++++++++++--- mm/vmalloc.c | 1 + 32 files changed, 903 insertions(+), 108 deletions(-) create mode 100644 fs/netfs/iterator.c