From: Mike Snitzer <snitzer@redhat.com>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
Arnd Bergmann <arnd@arndb.de>, Shaohua Li <shli@kernel.org>,
Alasdair Kergon <agk@redhat.com>,
dm-devel@redhat.com, Matthew Wilcox <mawilcox@microsoft.com>,
linux-fsdevel@vger.kernel.org,
Dan Williams <dan.j.williams@intel.com>,
Heinz Mauelshagen <heinzm@redhat.com>,
linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: dm-writecache: fix compilation issue with !DAX
Date: Wed, 30 May 2018 09:13:27 -0400 [thread overview]
Message-ID: <20180530131326.GA2106@redhat.com> (raw)
In-Reply-To: <alpine.LRH.2.02.1805300821510.24812@file01.intranet.prod.int.rdu2.redhat.com>
On Wed, May 30 2018 at 8:22am -0400,
Mikulas Patocka <mpatocka@redhat.com> wrote:
>
>
> On Tue, 29 May 2018, Ross Zwisler wrote:
>
> > As reported by Arnd (https://lkml.org/lkml/2018/5/28/1697), dm-writecache
> > will fail with link errors in configs where DAX isn't present:
> >
> > drivers/md/dm-writecache.o: In function `writecache_ctr':
> > dm-writecache.c:(.text+0x1fdc): undefined reference to `dax_read_lock'
> > dm-writecache.c:(.text+0x2004): undefined reference to `dax_direct_access'
> > dm-writecache.c:(.text+0x21cc): undefined reference to `dax_read_unlock'
> >
> > Fix this by following the lead of the other DM modules and wrapping calls
> > to the generic DAX code in #if IS_ENABLED(CONFIG_DAX_DRIVER) blocks.
> >
> > We also expand the failure case for the 'p' (persistent memory) flag so
> > that fails on both architectures that don't support persistent memory and
> > on kernels that don't have DAX support configured. This prevents us from
> > ever hitting the BUG() in the persistent_memory_claim() stub.
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Reported-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > drivers/md/dm-writecache.c | 16 ++++++++++++----
> > 1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> > index 92af65fdf4af..1c2b53ae1a96 100644
> > --- a/drivers/md/dm-writecache.c
> > +++ b/drivers/md/dm-writecache.c
> > @@ -253,6 +253,7 @@ static void wc_unlock(struct dm_writecache *wc)
> > mutex_unlock(&wc->lock);
> > }
> >
> > +#if IS_ENABLED(CONFIG_DAX_DRIVER)
>
> We already have #if(n)def DM_WRITECACHE_ONLY_SSD
>
> There is no need to use another macro for the same purpose.
I removed DM_WRITECACHE_ONLY_SSD because it wasn't needed, this is the
split out commit that I have since folded in:
https://git.kernel.org/pub/scm/linux/kernel/git/snitzer/linux.git/commit/?h=dm-4.18-writecache-wip&id=e7fd3d1c05659f7e1295178290fbdaebf36becdc
Ross's patch effectively builds ontop of that.
Mike
next prev parent reply other threads:[~2018-05-30 13:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-28 15:38 [PATCH] dm: writecache: add DAX dependency Arnd Bergmann
2018-05-28 18:18 ` Dan Williams
2018-05-29 13:06 ` Mike Snitzer
2018-05-29 15:17 ` [PATCH] " Ross Zwisler
2018-05-29 17:52 ` [PATCH] dm-writecache: fix compilation issue with !DAX Ross Zwisler
2018-05-29 18:08 ` Mike Snitzer
2018-05-29 18:40 ` Dan Williams
2018-05-29 19:57 ` Mike Snitzer
2018-05-30 12:22 ` [PATCH] " Mikulas Patocka
2018-05-30 13:13 ` Mike Snitzer [this message]
2018-05-30 12:21 ` [PATCH] dm: writecache: add DAX dependency Mikulas Patocka
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