On Thu, Jan 24, 2019 at 09:24:31AM +0100, Joerg Roedel wrote: > On Wed, Jan 23, 2019 at 10:28:13PM +0100, Christoph Hellwig wrote: > > On Wed, Jan 23, 2019 at 05:30:45PM +0100, Joerg Roedel wrote: > > > +extern size_t swiotlb_max_mapping_size(struct device *dev); > > > > No need for the extern keyword on function declarations in headers. > > Right, but all other function declarations in that header file have > 'extern' too, so I added it also for that one. Your patch 3 also doesn't use an extern. And I have to say I much prefer it that way..