From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753343AbbKAXnH (ORCPT ); Sun, 1 Nov 2015 18:43:07 -0500 Received: from mail-pa0-f50.google.com ([209.85.220.50]:32933 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752741AbbKAXnE (ORCPT ); Sun, 1 Nov 2015 18:43:04 -0500 Date: Mon, 2 Nov 2015 08:43:58 +0900 From: Sergey Senozhatsky To: Geliang Tang Cc: Minchan Kim , Andrew Morton , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: Re: [PATCH] zram: move init_done check to the beginning of disksize_store Message-ID: <20151101234358.GA4783@swordfish> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 (10/31/15 22:50), Geliang Tang wrote: > > If we set disksize when disksize has been set, we will get the following > error report: "write error: Cannot allocate memory". This is because > disksize_store fails at zram_meta_alloc. Those things are not connected, absolutely. zram_meta_alloc() can fail even on un-initialized device. In any case disksize_store() does not end up changing the state of the device and reports the error back, so I don't see any real value in this change. Seems that we come across this change something like once a year (this patch is not the first). I believe it has to stay the way it is, see https://lkml.org/lkml/2014/2/27/674 -ss > This is not what we expect. > To solve this problem, this patch moves init_done check to the beginning > of disksize_store. > > Signed-off-by: Geliang Tang > --- > drivers/block/zram/zram_drv.c | 17 ++++++++--------- > 1 file changed, 8 insertions(+), 9 deletions(-) > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 81a557c..609fc2b 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -1028,6 +1028,14 @@ static ssize_t disksize_store(struct device *dev, > struct zram *zram = dev_to_zram(dev); > int err; > > + down_read(&zram->init_lock); > + if (init_done(zram)) { > + up_read(&zram->init_lock); > + pr_info("Cannot change disksize for initialized device\n"); > + return -EBUSY; > + } > + up_read(&zram->init_lock); > + > disksize = memparse(buf, NULL); > if (!disksize) > return -EINVAL; > @@ -1046,12 +1054,6 @@ static ssize_t disksize_store(struct device *dev, > } > > down_write(&zram->init_lock); > - if (init_done(zram)) { > - pr_info("Cannot change disksize for initialized device\n"); > - err = -EBUSY; > - goto out_destroy_comp; > - } > - > init_waitqueue_head(&zram->io_done); > atomic_set(&zram->refcount, 1); > zram->meta = meta; > @@ -1069,9 +1071,6 @@ static ssize_t disksize_store(struct device *dev, > > return len; > > -out_destroy_comp: > - up_write(&zram->init_lock); > - zcomp_destroy(comp); > out_free_meta: > zram_meta_free(meta, disksize); > return err; > -- > 2.4.3 > >