From patchwork Thu Mar 14 10:35:43 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 227613 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id A357D2C0082 for ; Thu, 14 Mar 2013 21:42:43 +1100 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UG5cL-0000CD-Pk; Thu, 14 Mar 2013 10:42:37 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1UG5Xa-0006Bc-C3 for kernel-team@lists.ubuntu.com; Thu, 14 Mar 2013 10:37:42 +0000 Received: from bl15-242-192.dsl.telepac.pt ([188.80.242.192] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1UG5Xa-0003nD-31; Thu, 14 Mar 2013 10:37:42 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com 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 Cc: Pekka Enberg , Minchan Kim , Greg Kroah-Hartman X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 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;