From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 2E78C6B0005 for ; Wed, 11 May 2016 04:15:38 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id s63so35332360wme.2 for ; Wed, 11 May 2016 01:15:38 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id c12si8361646wmc.2.2016.05.11.01.15.35 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 11 May 2016 01:15:35 -0700 (PDT) Date: Wed, 11 May 2016 10:15:32 +0200 From: Jan Kara Subject: Re: [PATCH v6 4/5] dax: for truncate/hole-punch, do zeroing through the driver if possible Message-ID: <20160511081532.GB14744@quack2.suse.cz> References: <1462906156-22303-1-git-send-email-vishal.l.verma@intel.com> <1462906156-22303-5-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: <1462906156-22303-5-git-send-email-vishal.l.verma@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Vishal Verma Cc: linux-nvdimm@lists.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 On Tue 10-05-16 12:49:15, Vishal Verma wrote: > In the truncate or hole-punch path in dax, we clear out sub-page ranges. > If these sub-page ranges are sector aligned and sized, we can do the > zeroing through the driver instead so that error-clearing is handled > automatically. > > For sub-sector ranges, we still have to rely on clear_pmem and have the > possibility of tripping over errors. > > Cc: Dan Williams > Cc: Ross Zwisler > Cc: Jeff Moyer > Cc: Christoph Hellwig > Cc: Dave Chinner > Cc: Jan Kara > Reviewed-by: Christoph Hellwig > Signed-off-by: Vishal Verma ... > +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 (!IS_ALIGNED(((u64)dax->addr + offset), sector_size)) One more question: 'dax' is initialized in dax_zero_page_range() and dax->addr is going to be always NULL here. So either you forgot to call dax_map_atomic() to get the addr or the use of dax->addr is just bogus (which is what I currently believe since I see no way how the address could be unaligned with the sector_size)... Honza > + return false; > + if (!IS_ALIGNED(length, sector_size)) > + return false; > + > + return true; > +} > + > /** > * dax_zero_page_range - zero a range within a page of a DAX file > * @inode: The file being truncated > @@ -1240,11 +1254,16 @@ 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 >> 9, GFP_NOFS, true); > + else { > + 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); > + } > } > > return 0; > -- > 2.5.5 > -- Jan Kara SUSE Labs, CR -- 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