From nobody Mon Dec 15 23:00:43 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E4F6F199A4 for ; Wed, 3 Jan 2024 09:16:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SB6vapr0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1704273381; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=e2/9/uEWavAhcbGvkqENWO1xIuQmr8G4qpstfk2UpBk=; b=SB6vapr06Lb6yI0WaNz1St8AEfA19VPHQFdHLwyTNh9fQdlFzbkPAqvZPIIZ0oAWtqjOTd MpodwMLBOZ8SzVCe4SHZMUj23JYff4K2HD9IvmPT65l/MnpdgYXkomYJ0c7+HDstBce8Zo Hn6kwWZmITn/00kubCwMODHxJXtI0aU= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-562-bfNmJltGNpCYZPt_-QXM8w-1; Wed, 03 Jan 2024 04:16:16 -0500 X-MC-Unique: bfNmJltGNpCYZPt_-QXM8w-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 633D085CBA5; Wed, 3 Jan 2024 09:16:15 +0000 (UTC) Received: from x1n.redhat.com (unknown [10.72.116.69]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6E9FD492BE6; Wed, 3 Jan 2024 09:16:05 +0000 (UTC) From: peterx@redhat.com To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: James Houghton , David Hildenbrand , "Kirill A . Shutemov" , Yang Shi , peterx@redhat.com, linux-riscv@lists.infradead.org, Andrew Morton , "Aneesh Kumar K . V" , Rik van Riel , Andrea Arcangeli , Axel Rasmussen , Mike Rapoport , John Hubbard , Vlastimil Babka , Michael Ellerman , Christophe Leroy , Andrew Jones , linuxppc-dev@lists.ozlabs.org, Mike Kravetz , Muchun Song , linux-arm-kernel@lists.infradead.org, Jason Gunthorpe , Christoph Hellwig , Lorenzo Stoakes , Matthew Wilcox Subject: [PATCH v2 08/13] mm/gup: Handle hugetlb for no_page_table() Date: Wed, 3 Jan 2024 17:14:18 +0800 Message-ID: <20240103091423.400294-9-peterx@redhat.com> In-Reply-To: <20240103091423.400294-1-peterx@redhat.com> References: <20240103091423.400294-1-peterx@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 Content-Type: text/plain; charset="utf-8" From: Peter Xu no_page_table() is not yet used for hugetlb code paths. Make it prepared. The major difference here is hugetlb will return -EFAULT as long as page cache does not exist, even if VM_SHARED. See hugetlb_follow_page_mask(). Pass "address" into no_page_table() too, as hugetlb will need it. Reviewed-by: Christoph Hellwig Signed-off-by: Peter Xu Reviewed-by: Jason Gunthorpe --- mm/gup.c | 44 ++++++++++++++++++++++++++------------------ 1 file changed, 26 insertions(+), 18 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 3813aad79c4a..b8a80e2bfe08 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -501,19 +501,27 @@ static inline void mm_set_has_pinned_flag(unsigned lo= ng *mm_flags) =20 #ifdef CONFIG_MMU static struct page *no_page_table(struct vm_area_struct *vma, - unsigned int flags) + unsigned int flags, unsigned long address) { + if (!(flags & FOLL_DUMP)) + return NULL; + /* - * When core dumping an enormous anonymous area that nobody - * has touched so far, we don't want to allocate unnecessary pages or + * When core dumping, we don't want to allocate unnecessary pages or * page tables. Return error instead of NULL to skip handle_mm_fault, * then get_dump_page() will return NULL to leave a hole in the dump. * But we can only make this optimization where a hole would surely * be zero-filled if handle_mm_fault() actually did handle it. */ - if ((flags & FOLL_DUMP) && - (vma_is_anonymous(vma) || !vma->vm_ops->fault)) + if (is_vm_hugetlb_page(vma)) { + struct hstate *h =3D hstate_vma(vma); + + if (!hugetlbfs_pagecache_present(h, vma, address)) + return ERR_PTR(-EFAULT); + } else if ((vma_is_anonymous(vma) || !vma->vm_ops->fault)) { return ERR_PTR(-EFAULT); + } + return NULL; } =20 @@ -593,7 +601,7 @@ static struct page *follow_page_pte(struct vm_area_stru= ct *vma, =20 ptep =3D pte_offset_map_lock(mm, pmd, address, &ptl); if (!ptep) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); pte =3D ptep_get(ptep); if (!pte_present(pte)) goto no_page; @@ -685,7 +693,7 @@ static struct page *follow_page_pte(struct vm_area_stru= ct *vma, pte_unmap_unlock(ptep, ptl); if (!pte_none(pte)) return NULL; - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); } =20 static struct page *follow_pmd_mask(struct vm_area_struct *vma, @@ -701,27 +709,27 @@ static struct page *follow_pmd_mask(struct vm_area_st= ruct *vma, pmd =3D pmd_offset(pudp, address); pmdval =3D pmdp_get_lockless(pmd); if (pmd_none(pmdval)) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); if (!pmd_present(pmdval)) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); if (pmd_devmap(pmdval)) { ptl =3D pmd_lock(mm, pmd); page =3D follow_devmap_pmd(vma, address, pmd, flags, &ctx->pgmap); spin_unlock(ptl); if (page) return page; - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); } if (likely(!pmd_trans_huge(pmdval))) return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap); =20 if (pmd_protnone(pmdval) && !gup_can_follow_protnone(vma, flags)) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); =20 ptl =3D pmd_lock(mm, pmd); if (unlikely(!pmd_present(*pmd))) { spin_unlock(ptl); - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); } if (unlikely(!pmd_trans_huge(*pmd))) { spin_unlock(ptl); @@ -752,17 +760,17 @@ static struct page *follow_pud_mask(struct vm_area_st= ruct *vma, =20 pud =3D pud_offset(p4dp, address); if (pud_none(*pud)) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); if (pud_devmap(*pud)) { ptl =3D pud_lock(mm, pud); page =3D follow_devmap_pud(vma, address, pud, flags, &ctx->pgmap); spin_unlock(ptl); if (page) return page; - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); } if (unlikely(pud_bad(*pud))) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); =20 return follow_pmd_mask(vma, address, pud, flags, ctx); } @@ -776,10 +784,10 @@ static struct page *follow_p4d_mask(struct vm_area_st= ruct *vma, =20 p4d =3D p4d_offset(pgdp, address); if (p4d_none(*p4d)) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); BUILD_BUG_ON(p4d_huge(*p4d)); if (unlikely(p4d_bad(*p4d))) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); =20 return follow_pud_mask(vma, address, p4d, flags, ctx); } @@ -829,7 +837,7 @@ static struct page *follow_page_mask(struct vm_area_str= uct *vma, pgd =3D pgd_offset(mm, address); =20 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) - return no_page_table(vma, flags); + return no_page_table(vma, flags, address); =20 return follow_p4d_mask(vma, address, pgd, flags, ctx); } --=20 2.41.0