From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 10B396B0292 for ; Tue, 20 Jun 2017 02:21:08 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id p190so14245406wme.3 for ; Mon, 19 Jun 2017 23:21:08 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id l7si2683672wml.156.2017.06.19.23.21.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 19 Jun 2017 23:21:06 -0700 (PDT) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v5K6Ii41068580 for ; Tue, 20 Jun 2017 02:21:05 -0400 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0b-001b2d01.pphosted.com with ESMTP id 2b6qen6q0e-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 20 Jun 2017 02:21:05 -0400 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 20 Jun 2017 07:21:02 +0100 From: Mike Rapoport Subject: [PATCH 1/7] shmem: shmem_charge: verify max_block is not exceeded before inode update Date: Tue, 20 Jun 2017 09:20:46 +0300 In-Reply-To: <1497939652-16528-1-git-send-email-rppt@linux.vnet.ibm.com> References: <1497939652-16528-1-git-send-email-rppt@linux.vnet.ibm.com> Message-Id: <1497939652-16528-2-git-send-email-rppt@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Andrea Arcangeli , Hugh Dickins , "Kirill A. Shutemov" , Hillf Danton , Pavel Emelyanov , linux mm , lkml , Mike Rapoport Currently we update inode and shmem_inode_info before verifying that used_blocks will not exceed max_blocks. In case it will, we undo the update. Let's switch the order and move the verification of the blocks count before the inode and shmem_inode_info update. Signed-off-by: Mike Rapoport --- mm/shmem.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index e67d6ba..40a43ae 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -265,6 +265,14 @@ bool shmem_charge(struct inode *inode, long pages) if (shmem_acct_block(info->flags, pages)) return false; + + if (sbinfo->max_blocks) { + if (percpu_counter_compare(&sbinfo->used_blocks, + sbinfo->max_blocks - pages) > 0) + goto unacct; + percpu_counter_add(&sbinfo->used_blocks, pages); + } + spin_lock_irqsave(&info->lock, flags); info->alloced += pages; inode->i_blocks += pages * BLOCKS_PER_PAGE; @@ -272,20 +280,11 @@ bool shmem_charge(struct inode *inode, long pages) spin_unlock_irqrestore(&info->lock, flags); inode->i_mapping->nrpages += pages; - if (!sbinfo->max_blocks) - return true; - if (percpu_counter_compare(&sbinfo->used_blocks, - sbinfo->max_blocks - pages) > 0) { - inode->i_mapping->nrpages -= pages; - spin_lock_irqsave(&info->lock, flags); - info->alloced -= pages; - shmem_recalc_inode(inode); - spin_unlock_irqrestore(&info->lock, flags); - shmem_unacct_blocks(info->flags, pages); - return false; - } - percpu_counter_add(&sbinfo->used_blocks, pages); return true; + +unacct: + shmem_unacct_blocks(info->flags, pages); + return false; } void shmem_uncharge(struct inode *inode, long pages) -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org