Re: [PATCH] firmware_loader: re-export fw_fallback_config into firmware_loader's own namespace

[Luis Chamberlain]

On Thu, Apr 23, 2020 at 07:27:16PM -0700, Jakub Kicinski wrote:
> On Fri, 24 Apr 2020 02:14:20 +0000 Luis Chamberlain wrote:
> > On Thu, Apr 23, 2020 at 06:05:44PM -0700, Jakub Kicinski wrote:
> > > On Thu, 23 Apr 2020 20:31:40 +0000 Luis R. Rodriguez wrote:  
> > > > From: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> > > > 
> > > > Christoph's recent patch "firmware_loader: remove unused exports", which
> > > > is not merged upstream yet, removed two exported symbols. One is fine to
> > > > remove since only built-in code uses it but the other is incorrect.
> > > > 
> > > > If CONFIG_FW_LOADER=m so the firmware_loader is modular but
> > > > CONFIG_FW_LOADER_USER_HELPER=y we fail at mostpost with:
> > > > 
> > > > ERROR: modpost: "fw_fallback_config" [drivers/base/firmware_loader/firmware_class.ko] undefined!
> > > > 
> > > > This happens because the variable fw_fallback_config is built into the
> > > > kernel if CONFIG_FW_LOADER_USER_HELPER=y always, so we need to grant
> > > > access to the firmware loader module by exporting it.
> > > > 
> > > > Instead of just exporting it as we used to, take advantage of the new
> > > > kernel symbol namespacing functionality, and export the symbol only to
> > > > the firmware loader private namespace. This would prevent misuses from
> > > > other drivers and makes it clear the goal is to keep this private to
> > > > the firmware loader alone.
> > > > 
> > > > Cc: Christoph Hellwig <hch@xxxxxx>
> > > > Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> > > > Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> > > > Fixes: "firmware_loader: remove unused exports"  
> > > 
> > > Can't help but notice this strange form of the Fixes tag, is it
> > > intentional?  
> > 
> > Yeah, no there is no commit for the patch as the commit is ephemeral in
> > a development tree not yet upstream, ie, not on Linus' tree yet. Using a
> > commit here then makes no sense unless one wants to use a reference
> > development tree in this case, as development trees are expected to
> > rebase to move closer towards Linus' tree. When a tree rebases, the
> > commit IDs change, and this is why the commit is ephemeral unless
> > one uses a base tree / branch / tag.
> 
> I'd think that either the commit is rebase-able and the fix can be
> squashed into it, or it's not and it has a stable commit id. 
> But I guess it may get tricky around the edges..

I'll let Greg decide ;)

I did my part.

  Luis