Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932273AbaJ1Dlz (ORCPT ); Mon, 27 Oct 2014 23:41:55 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44980 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932226AbaJ1Dlp (ORCPT ); Mon, 27 Oct 2014 23:41:45 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "David S. Miller" Subject: [PATCH 3.17 146/146] sparc64: Implement __get_user_pages_fast(). Date: Tue, 28 Oct 2014 11:34:48 +0800 Message-Id: <20141028033349.802373125@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141028033343.441992423@linuxfoundation.org> References: <20141028033343.441992423@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: "David S. Miller" [ Upstream commit 06090e8ed89ea2113a236befb41f71d51f100e60 ] It is not sufficient to only implement get_user_pages_fast(), you must also implement the atomic version __get_user_pages_fast() otherwise you end up using the weak symbol fallback implementation which simply returns zero. This is dangerous, because it causes the futex code to loop forever if transparent hugepages are supported (see get_futex_key()). Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- arch/sparc/mm/gup.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) --- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -160,6 +160,36 @@ static int gup_pud_range(pgd_t pgd, unsi return 1; } +int __get_user_pages_fast(unsigned long start, int nr_pages, int write, + struct page **pages) +{ + struct mm_struct *mm = current->mm; + unsigned long addr, len, end; + unsigned long next, flags; + pgd_t *pgdp; + int nr = 0; + + start &= PAGE_MASK; + addr = start; + len = (unsigned long) nr_pages << PAGE_SHIFT; + end = start + len; + + local_irq_save(flags); + pgdp = pgd_offset(mm, addr); + do { + pgd_t pgd = *pgdp; + + next = pgd_addr_end(addr, end); + if (pgd_none(pgd)) + break; + if (!gup_pud_range(pgd, addr, next, write, pages, &nr)) + break; + } while (pgdp++, addr = next, addr != end); + local_irq_restore(flags); + + return nr; +} + int get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/