From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757225Ab3CNKhs (ORCPT ); Thu, 14 Mar 2013 06:37:48 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:51948 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757184Ab3CNKhn (ORCPT ); Thu, 14 Mar 2013 06:37:43 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Pekka Enberg , Minchan Kim , Greg Kroah-Hartman , Luis Henriques Subject: [PATCH 50/88] zram: Fix deadlock bug in partial read/write Date: Thu, 14 Mar 2013 10:35:43 +0000 Message-Id: <1363257381-15900-51-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1363257381-15900-1-git-send-email-luis.henriques@canonical.com> References: <1363257381-15900-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.8 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Minchan Kim commit 7e5a5104c6af709a8d97d5f4711e7c917761d464 upstream. Now zram allocates new page with GFP_KERNEL in zram I/O path if IO is partial. Unfortunately, It may cause deadlock with reclaim path like below. write_page from fs fs_lock allocation(GFP_KERNEL) reclaim pageout write_page from fs fs_lock <-- deadlock This patch fixes it by using GFP_NOIO. In read path, we reorganize code flow so that kmap_atomic is called after the GFP_NOIO allocation. Acked-by: Jerome Marchand Acked-by: Nitin Gupta [ penberg@kernel.org: don't use GFP_ATOMIC ] Signed-off-by: Pekka Enberg Signed-off-by: Minchan Kim Signed-off-by: Greg Kroah-Hartman Signed-off-by: Luis Henriques --- drivers/staging/zram/zram_drv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 685d612..fb7f9fb 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -235,7 +235,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, if (is_partial_io(bvec)) { /* Use a temporary buffer to decompress the page */ - uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); if (!uncmem) { pr_info("Error allocating temp memory!\n"); return -ENOMEM; @@ -330,7 +330,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, * This is a partial IO. We need to read the full page * before to write the changes. */ - uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL); + uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); if (!uncmem) { pr_info("Error allocating temp memory!\n"); ret = -ENOMEM; -- 1.8.1.2