From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753142AbcFFRrD (ORCPT ); Mon, 6 Jun 2016 13:47:03 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:28619 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752451AbcFFRrA (ORCPT ); Mon, 6 Jun 2016 13:47:00 -0400 From: Mike Kravetz To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Andrea Arcangeli , Hugh Dickins , Dave Hansen , "Kirill A. Shutemov" , Naoya Horiguchi , Hillf Danton , Michal Hocko , Andrew Morton , Mike Kravetz Subject: [RFC PATCH 1/6] mm/memory: add copy_huge_page_from_user for hugetlb userfaultfd support Date: Mon, 6 Jun 2016 10:45:26 -0700 Message-Id: <1465235131-6112-2-git-send-email-mike.kravetz@oracle.com> X-Mailer: git-send-email 2.4.11 In-Reply-To: <1465235131-6112-1-git-send-email-mike.kravetz@oracle.com> References: <1465235131-6112-1-git-send-email-mike.kravetz@oracle.com> X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org userfaultfd UFFDIO_COPY allows user level code to copy data to a page at fault time. The data is copied from user space to a newly allocated huge page. The new routine copy_huge_page_from_user performs this copy. Signed-off-by: Mike Kravetz --- include/linux/mm.h | 3 +++ mm/memory.c | 22 ++++++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 0510282..7ecc7e7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2355,6 +2355,9 @@ extern void clear_huge_page(struct page *page, extern void copy_user_huge_page(struct page *dst, struct page *src, unsigned long addr, struct vm_area_struct *vma, unsigned int pages_per_huge_page); +extern long copy_huge_page_from_user(const void __user *usr_src, + struct page *dst_page, + unsigned int pages_per_huge_page); #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ extern struct page_ext_operations debug_guardpage_ops; diff --git a/mm/memory.c b/mm/memory.c index 19584b9..c44ddad 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3970,6 +3970,28 @@ void copy_user_huge_page(struct page *dst, struct page *src, copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); } } + +long copy_huge_page_from_user(const void __user *usr_src, + struct page *dst_page, + unsigned int pages_per_huge_page) +{ + void *src = (void *)usr_src; + void *page_kaddr; + long i, rc = 0; + + for (i = 0; i < pages_per_huge_page; i++) { + page_kaddr = kmap_atomic(dst_page + i); + rc = copy_from_user(page_kaddr, + (const void __user *)(src + i * PAGE_SIZE), + PAGE_SIZE); + kunmap_atomic(page_kaddr); + if (rc) + break; + + cond_resched(); + } + return rc; +} #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS -- 2.4.11