From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: dm-writecache: fix compilation issue with !DAX Date: Tue, 29 May 2018 14:08:23 -0400 Message-ID: <20180529180823.GA32763@redhat.com> References: <20180528153834.2268557-1-arnd@arndb.de> <20180529175216.24937-1-ross.zwisler@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180529175216.24937-1-ross.zwisler@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Ross Zwisler Cc: Arnd Bergmann , Mikulas Patocka , Shaohua Li , Alasdair Kergon , dm-devel@redhat.com, Matthew Wilcox , linux-fsdevel@vger.kernel.org, Dan Williams , Heinz Mauelshagen , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-raid.ids On Tue, May 29 2018 at 1:52pm -0400, 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 > Reported-by: Arnd Bergmann Thanks, I've picked this up. Mike