From patchwork Wed Aug 21 04:03:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Hubbard X-Patchwork-Id: 11105385 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 0D3E71813 for ; Wed, 21 Aug 2019 04:04:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D69292332A for ; Wed, 21 Aug 2019 04:04:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="nhL1HSK2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727326AbfHUEEA (ORCPT ); Wed, 21 Aug 2019 00:04:00 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:18775 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725866AbfHUEEA (ORCPT ); Wed, 21 Aug 2019 00:04:00 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Tue, 20 Aug 2019 21:03:58 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Tue, 20 Aug 2019 21:03:58 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Tue, 20 Aug 2019 21:03:58 -0700 Received: from HQMAIL110.nvidia.com (172.18.146.15) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 21 Aug 2019 04:03:57 +0000 Received: from HQMAIL111.nvidia.com (172.20.187.18) by hqmail110.nvidia.com (172.18.146.15) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 21 Aug 2019 04:03:57 +0000 Received: from hqnvemgw02.nvidia.com (172.16.227.111) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Wed, 21 Aug 2019 04:03:57 +0000 Received: from blueforge.nvidia.com (Not Verified[10.110.48.28]) by hqnvemgw02.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Tue, 20 Aug 2019 21:03:57 -0700 From: John Hubbard To: Andrew Morton CC: Christoph Hellwig , Dan Williams , Dave Chinner , Ira Weiny , Jan Kara , Jason Gunthorpe , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Vlastimil Babka , LKML , , , , John Hubbard Subject: [PATCH 4/4] mm/gup: introduce vaddr_pin_pages_remote(), and invoke it Date: Tue, 20 Aug 2019 21:03:55 -0700 Message-ID: <20190821040355.19566-4-jhubbard@nvidia.com> X-Mailer: git-send-email 2.22.1 In-Reply-To: <20190821040355.19566-1-jhubbard@nvidia.com> References: <20190821040355.19566-1-jhubbard@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1566360238; bh=84bhj2PTobIrNB4qrJQexuzhd7TgFsVEFFO7B0hh5tU=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=nhL1HSK2U4WrKC5vGw3005UMictu1E4EM+yEDzDmb6ZkyWfRgLvFtM7196fevI5sV GXmipG5tsboszbdoEPIJy0512aMsw78D+8KclfySfhJeY74wtgtdl9tzr9YvK03S0F d9PC4sNf31/PgrnlUlmK0M1k1S7zdRM39LPfT2OkKqrNba4Kewa1lGY2MxXQE16M9i yPtAlQWhCfrDDRKVlTvz3MH9E+1UzGRAevREc/6foOp3DNrMo31pgLtt+1Br8HvKPn RX4BTFbIm2RUzGmbp9kDWvkaiGUYHSV5AQ/XpeX0xE0Y3fOw18V/JdP7PqrECgIl86 PeNFAAGpzLlNQ== Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org vaddr_pin_user_pages_remote() is the "vaddr_pin_pages" corresponding variant to get_user_pages_remote(): it adds the ability to handle FOLL_PIN, FOLL_LONGTERM, or both. Note that the put_user_page*() requirement won't be truly required until all of the call sites have been converted, and the tracking of pages is activated. Also, change process_vm_rw_single_vec() to invoke the new function. Signed-off-by: John Hubbard --- include/linux/mm.h | 5 +++++ mm/gup.c | 33 +++++++++++++++++++++++++++++++++ mm/process_vm_access.c | 23 ++++++++++++++--------- 3 files changed, 52 insertions(+), 9 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 6e7de424bf5e..849b509e9f89 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1606,6 +1606,11 @@ int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, long vaddr_pin_pages(unsigned long addr, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, struct vaddr_pin *vaddr_pin); +long vaddr_pin_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + unsigned int gup_flags, struct page **pages, + struct vm_area_struct **vmas, int *locked, + struct vaddr_pin *vaddr_pin); void vaddr_unpin_pages(struct page **pages, unsigned long nr_pages, struct vaddr_pin *vaddr_pin, bool make_dirty); bool mapping_inode_has_layout(struct vaddr_pin *vaddr_pin, struct page *page); diff --git a/mm/gup.c b/mm/gup.c index e49096d012ea..d7ce9b38178f 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2522,3 +2522,36 @@ void vaddr_unpin_pages(struct page **pages, unsigned long nr_pages, __put_user_pages_dirty_lock(pages, nr_pages, make_dirty, vaddr_pin); } EXPORT_SYMBOL(vaddr_unpin_pages); + +/** + * vaddr_pin_user_pages_remote() - pin pages by virtual address and return the + * pages to the user. + * + * @tsk: the task_struct to use for page fault accounting, or + * NULL if faults are not to be recorded. + * @mm: mm_struct of target mm + * @addr: start address + * @nr_pages: number of pages to pin + * @gup_flags: flags to use for the pin. Please see FOLL_* documentation in + * mm.h. + * @pages: array of pages returned + * @vaddr_pin: If FOLL_LONGTERM is set, then vaddr_pin should point to an + * initialized struct that contains the owning mm and file. Otherwise, vaddr_pin + * should be set to NULL. + * + * This is the "vaddr_pin_pages" corresponding variant to + * get_user_pages_remote(), but with the ability to handle FOLL_PIN, + * FOLL_LONGTERM, or both. + */ +long vaddr_pin_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, + unsigned long start, unsigned long nr_pages, + unsigned int gup_flags, struct page **pages, + struct vm_area_struct **vmas, int *locked, + struct vaddr_pin *vaddr_pin) +{ + gup_flags |= FOLL_TOUCH | FOLL_REMOTE; + + return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, + locked, gup_flags, vaddr_pin); +} +EXPORT_SYMBOL(vaddr_pin_user_pages_remote); diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 357aa7bef6c0..e08c1f760ad4 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -96,7 +96,7 @@ static int process_vm_rw_single_vec(unsigned long addr, flags |= FOLL_WRITE; while (!rc && nr_pages && iov_iter_count(iter)) { - int pages = min(nr_pages, max_pages_per_loop); + int pinned_pages = min(nr_pages, max_pages_per_loop); int locked = 1; size_t bytes; @@ -106,14 +106,18 @@ static int process_vm_rw_single_vec(unsigned long addr, * current/current->mm */ down_read(&mm->mmap_sem); - pages = get_user_pages_remote(task, mm, pa, pages, flags, - process_pages, NULL, &locked); + + flags |= FOLL_PIN; + pinned_pages = vaddr_pin_user_pages_remote(task, mm, pa, + pinned_pages, flags, + process_pages, NULL, + &locked, NULL); if (locked) up_read(&mm->mmap_sem); - if (pages <= 0) + if (pinned_pages <= 0) return -EFAULT; - bytes = pages * PAGE_SIZE - start_offset; + bytes = pinned_pages * PAGE_SIZE - start_offset; if (bytes > len) bytes = len; @@ -122,10 +126,11 @@ static int process_vm_rw_single_vec(unsigned long addr, vm_write); len -= bytes; start_offset = 0; - nr_pages -= pages; - pa += pages * PAGE_SIZE; - while (pages) - put_page(process_pages[--pages]); + nr_pages -= pinned_pages; + pa += pinned_pages * PAGE_SIZE; + + /* If vm_write is set, the pages need to be made dirty: */ + vaddr_unpin_pages(process_pages, pinned_pages, NULL, vm_write); } return rc;