From patchwork Fri Oct 21 17:41:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Logan Gunthorpe X-Patchwork-Id: 13015232 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 0B15BFA3743 for ; Fri, 21 Oct 2022 17:41:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230398AbiJURli (ORCPT ); Fri, 21 Oct 2022 13:41:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230086AbiJURla (ORCPT ); Fri, 21 Oct 2022 13:41:30 -0400 Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F411324AE39; Fri, 21 Oct 2022 10:41:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:MIME-Version:References:In-Reply-To: Message-Id:Date:Cc:To:From:content-disposition; bh=ZKzeHAseABZVh8sd+FhS8dmH5rKh2MAqOmNnK2azrFk=; b=SCPNrRDZ9UU4DpltRcbsssgmyI AHJvEMgJpBj9GsQW3ewgt9CMYRzjTXS2pClQa/iJ5O4KclRX5lVa5tsEEz3BY9MiZ/70kt6YKTKon adDQ6Rz1R9tvT9HgxUS6OnkIq96l33Z1f2ijTn5iFaT8UgRTVw/sR9htaLNNeMp7lvcHWXl4FZliC OiKr0d1TOW4sUqigC0T9LjQxmVKBf09QghSF5km2kvs/fxlTr4tSNAK5c80z7xXFmKdDy9/Lr/GBZ CUUng/vaRDjJEJ3Yc5bszWou2LyaJq0lEQsl9M7kL9ztyr33ASxSAgOOoQm7IvyeGp0SSewunrXTJ 1iyfFsKg==; Received: from cgy1-donard.priv.deltatee.com ([172.16.1.31]) by ale.deltatee.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1olw1I-00DoHy-T8; Fri, 21 Oct 2022 11:41:22 -0600 Received: from gunthorp by cgy1-donard.priv.deltatee.com with local (Exim 4.94.2) (envelope-from ) id 1olw1F-0001t6-LU; Fri, 21 Oct 2022 11:41:17 -0600 From: Logan Gunthorpe To: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org Cc: Christoph Hellwig , Greg Kroah-Hartman , Dan Williams , Jason Gunthorpe , =?utf-8?q?Christian_K=C3=B6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni , Ralph Campbell , Stephen Bates , Logan Gunthorpe Date: Fri, 21 Oct 2022 11:41:08 -0600 Message-Id: <20221021174116.7200-2-logang@deltatee.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221021174116.7200-1-logang@deltatee.com> References: <20221021174116.7200-1-logang@deltatee.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 172.16.1.31 X-SA-Exim-Rcpt-To: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, hch@lst.de, gregkh@linuxfoundation.org, jgg@ziepe.ca, christian.koenig@amd.com, ddutile@redhat.com, willy@infradead.org, daniel.vetter@ffwll.ch, jason@jlekstrand.net, dave.hansen@linux.intel.com, helgaas@kernel.org, dan.j.williams@intel.com, dave.b.minturn@intel.com, jianxin.xiong@intel.com, ira.weiny@intel.com, robin.murphy@arm.com, martin.oliveira@eideticom.com, ckulkarnilinux@gmail.com, jhubbard@nvidia.com, rcampbell@nvidia.com, sbates@raithlin.com, logang@deltatee.com X-SA-Exim-Mail-From: gunthorp@deltatee.com Subject: [PATCH v11 1/9] mm: allow multiple error returns in try_grab_page() X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org In order to add checks for P2PDMA memory into try_grab_page(), expand the error return from a bool to an int/error code. Update all the callsites handle change in usage. Also remove the WARN_ON_ONCE() call at the callsites seeing there already is a WARN_ON_ONCE() inside the function if it fails. Signed-off-by: Logan Gunthorpe Reviewed-by: Christoph Hellwig Reviewed-by: Dan Williams Reviewed-by: Chaitanya Kulkarni --- include/linux/mm.h | 2 +- mm/gup.c | 26 ++++++++++++++------------ mm/huge_memory.c | 19 +++++++++++++------ mm/hugetlb.c | 17 +++++++++-------- 4 files changed, 37 insertions(+), 27 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8bbcccbc5565..62a91dc1272b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1129,7 +1129,7 @@ static inline void get_page(struct page *page) folio_get(page_folio(page)); } -bool __must_check try_grab_page(struct page *page, unsigned int flags); +int __must_check try_grab_page(struct page *page, unsigned int flags); static inline __must_check bool try_get_page(struct page *page) { diff --git a/mm/gup.c b/mm/gup.c index fe195d47de74..e2f447446384 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -202,17 +202,19 @@ static void gup_put_folio(struct folio *folio, int refs, unsigned int flags) * time. Cases: please see the try_grab_folio() documentation, with * "refs=1". * - * Return: true for success, or if no action was required (if neither FOLL_PIN - * nor FOLL_GET was set, nothing is done). False for failure: FOLL_GET or - * FOLL_PIN was set, but the page could not be grabbed. + * Return: 0 for success, or if no action was required (if neither FOLL_PIN + * nor FOLL_GET was set, nothing is done). A negative error code for failure: + * + * -ENOMEM FOLL_GET or FOLL_PIN was set, but the page could not + * be grabbed. */ -bool __must_check try_grab_page(struct page *page, unsigned int flags) +int __must_check try_grab_page(struct page *page, unsigned int flags) { struct folio *folio = page_folio(page); WARN_ON_ONCE((flags & (FOLL_GET | FOLL_PIN)) == (FOLL_GET | FOLL_PIN)); if (WARN_ON_ONCE(folio_ref_count(folio) <= 0)) - return false; + return -ENOMEM; if (flags & FOLL_GET) folio_ref_inc(folio); @@ -232,7 +234,7 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags) node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, 1); } - return true; + return 0; } /** @@ -624,8 +626,9 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, !PageAnonExclusive(page), page); /* try_grab_page() does nothing unless FOLL_GET or FOLL_PIN is set. */ - if (unlikely(!try_grab_page(page, flags))) { - page = ERR_PTR(-ENOMEM); + ret = try_grab_page(page, flags); + if (unlikely(ret)) { + page = ERR_PTR(ret); goto out; } /* @@ -960,10 +963,9 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, goto unmap; *page = pte_page(*pte); } - if (unlikely(!try_grab_page(*page, gup_flags))) { - ret = -ENOMEM; + ret = try_grab_page(*page, gup_flags); + if (unlikely(ret)) goto unmap; - } out: ret = 0; unmap: @@ -2536,7 +2538,7 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, } SetPageReferenced(page); pages[*nr] = page; - if (unlikely(!try_grab_page(page, flags))) { + if (unlikely(try_grab_page(page, flags))) { undo_dev_pagemap(nr, nr_start, flags, pages); break; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1cc4a5f4791e..52f2b2a2ffae 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1035,6 +1035,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn = pmd_pfn(*pmd); struct mm_struct *mm = vma->vm_mm; struct page *page; + int ret; assert_spin_locked(pmd_lockptr(mm, pmd)); @@ -1066,8 +1067,9 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr, if (!*pgmap) return ERR_PTR(-EFAULT); page = pfn_to_page(pfn); - if (!try_grab_page(page, flags)) - page = ERR_PTR(-ENOMEM); + ret = try_grab_page(page, flags); + if (ret) + page = ERR_PTR(ret); return page; } @@ -1193,6 +1195,7 @@ struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn = pud_pfn(*pud); struct mm_struct *mm = vma->vm_mm; struct page *page; + int ret; assert_spin_locked(pud_lockptr(mm, pud)); @@ -1226,8 +1229,10 @@ struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, if (!*pgmap) return ERR_PTR(-EFAULT); page = pfn_to_page(pfn); - if (!try_grab_page(page, flags)) - page = ERR_PTR(-ENOMEM); + + ret = try_grab_page(page, flags); + if (ret) + page = ERR_PTR(ret); return page; } @@ -1435,6 +1440,7 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, { struct mm_struct *mm = vma->vm_mm; struct page *page; + int ret; assert_spin_locked(pmd_lockptr(mm, pmd)); @@ -1459,8 +1465,9 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && !PageAnonExclusive(page), page); - if (!try_grab_page(page, flags)) - return ERR_PTR(-ENOMEM); + ret = try_grab_page(page, flags); + if (ret) + return ERR_PTR(ret); if (flags & FOLL_TOUCH) touch_pmd(vma, addr, pmd, flags & FOLL_WRITE); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index b586cdd75930..e8d01a19ce46 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -7224,14 +7224,15 @@ follow_huge_pmd_pte(struct vm_area_struct *vma, unsigned long address, int flags page = pte_page(pte) + ((address & ~huge_page_mask(h)) >> PAGE_SHIFT); /* - * try_grab_page() should always succeed here, because: a) we - * hold the pmd (ptl) lock, and b) we've just checked that the - * huge pmd (head) page is present in the page tables. The ptl - * prevents the head page and tail pages from being rearranged - * in any way. So this page must be available at this point, - * unless the page refcount overflowed: + * try_grab_page() should always be able to get the page here, + * because: a) we hold the pmd (ptl) lock, and b) we've just + * checked that the huge pmd (head) page is present in the + * page tables. The ptl prevents the head page and tail pages + * from being rearranged in any way. So this page must be + * available at this point, unless the page refcount + * overflowed: */ - if (WARN_ON_ONCE(!try_grab_page(page, flags))) { + if (try_grab_page(page, flags)) { page = NULL; goto out; } @@ -7269,7 +7270,7 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address, pte = huge_ptep_get((pte_t *)pud); if (pte_present(pte)) { page = pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT); - if (WARN_ON_ONCE(!try_grab_page(page, flags))) { + if (try_grab_page(page, flags)) { page = NULL; goto out; }