From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752791AbcEJOVZ (ORCPT ); Tue, 10 May 2016 10:21:25 -0400 Received: from mx2.suse.de ([195.135.220.15]:49333 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751740AbcEJOVX (ORCPT ); Tue, 10 May 2016 10:21:23 -0400 Date: Tue, 10 May 2016 16:21:19 +0200 From: Jan Kara To: Vishal Verma Cc: linux-nvdimm@ml01.01.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, xfs@oss.sgi.com, linux-ext4@vger.kernel.org, linux-mm@kvack.org, Ross Zwisler , Dan Williams , Dave Chinner , Jan Kara , Jens Axboe , Andrew Morton , linux-kernel@vger.kernel.org, Christoph Hellwig , Jeff Moyer , Boaz Harrosh Subject: Re: [PATCH v5 4/5] dax: for truncate/hole-punch, do zeroing through the driver if possible Message-ID: <20160510142119.GN11897@quack2.suse.cz> References: <1462571591-3361-1-git-send-email-vishal.l.verma@intel.com> <1462571591-3361-5-git-send-email-vishal.l.verma@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1462571591-3361-5-git-send-email-vishal.l.verma@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 06-05-16 15:53:10, Vishal Verma wrote: > +static bool dax_range_is_aligned(struct block_device *bdev, > + struct blk_dax_ctl *dax, unsigned int offset, > + unsigned int length) > +{ > + unsigned short sector_size = bdev_logical_block_size(bdev); > + > + if (((u64)dax->addr + offset) % sector_size) > + return false; > + if (length % sector_size) > + return false; sector_size should better be a power of two so you can save some cycles by using & instead of %. > @@ -1240,11 +1254,17 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length, > .size = PAGE_SIZE, > }; > > - if (dax_map_atomic(bdev, &dax) < 0) > - return PTR_ERR(dax.addr); > - clear_pmem(dax.addr + offset, length); > - wmb_pmem(); > - dax_unmap_atomic(bdev, &dax); > + if (dax_range_is_aligned(bdev, &dax, offset, length)) > + return blkdev_issue_zeroout(bdev, dax.sector, > + length / bdev_logical_block_size(bdev), > + GFP_NOFS, true); This is actually wrong. blkdev_issue_zeroout() expects length to be simply in units of 512-bytes. So you need length >> 9 here. Honza -- Jan Kara SUSE Labs, CR