svn commit: r221124 - in head: . sbin/mount sbin/mount_nfs sys/amd64/conf sys/fs/nfsclient sys/i386/conf sys/ia64/conf sys/nfsclient sys/pc98/conf sys/powerpc/conf sys/sparc64/conf sys/sun4v/conf

[Rick Macklem]

> Rick Macklem <rmacklem at uoguelph.ca> writes:
> > My problem is that I don't know how to deal with two modules with
> > the same name.
> 
> Why do they have to have the same name? All that matters is the fstype
> and the sysctls. Just make sure that the auto-load logic loads the new
> stack and not the old one if neither is loaded already.
> 
Well, the main auto-load logic is the (n)mount(2) syscall and it does
a vfs_byname_kld(fstype, td, errp), which calls
kern_kldload(td, fstype, &fileid) to load the module.
The argument is the "fstype", so that is what is used to find/load
the module. The way sys/nfsclient is set up (and I think this is the
norm for file systems), the module name is the fstype name, because

VFS_SET(nfs_vfsops, oldnfs, VFCF_NETWORK);
(There is a DECLARE_MODULE() in this macro and it uses the 2nd arg.
 to set the module name, same as the fstype name. Just take a look
 at the VFS_SET() macro in sys/mount.h.)

defines the module name as the 2nd argument, which is also the fstype.
(You can give it another "name" via DECLARE_MODULE(), although I'm not
 sure if that it considered correct to do, but it will be the "fstype"
 that the mount(2) syscall will use to try and load it.)

rick