On Sat, Aug 19, 2023 at 6:57 AM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Thu, Aug 17, 2023 at 07:58:09PM -0400, Alistair Francis wrote: > > The documentation for sysfs_merge_group() specifically says > > > > This function returns an error if the group doesn't exist or any of the > > files already exist in that group, in which case none of the new files > > are created. > > > > So just not adding the group if it's empty doesn't work, at least not > > with the code we currently have. The code can be changed to support > > this, but it is difficult to determine how this will affect existing use > > cases. > > Did you try? I'd really really really prefer we do it this way as it's > much simpler overall to have the sysfs core "do the right thing > automatically" than to force each and every bus/subsystem to have to > manually add this type of attribute. > > Also, on a personal level, I want this function to work as it will allow > us to remove some code in some busses that don't really need to be there > (dynamic creation of some device attributes), which will then also allow > me to remove some apis in the driver core that should not be used at all > anymore (but keep creeping back in as there is still a few users.) > > So I'll be selfish here and say "please try to get my proposed change to > work, it's really the correct thing to do here." I did try! This is an attempt: https://github.com/alistair23/linux/commit/56b55756a2d7a66f7b6eb8a5692b1b5e2f81a9a9 It is based on your original patch with a bunch of: if (!parent) { parent = kernfs_create_dir_ns(kobj->sd, grp->name, S_IRWXU | S_IRUGO | S_IXUGO, uid, gid, kobj, NULL); ... } added throughout the code base. Very basic testing shows that it does what I need it to do and I don't see any kernel oops on boot. I prefer the approach I have in this mailing list patch. But if you like the commit mentioned above I can tidy and clean it up and then use that instead Alistair > > thanks, > > greg k-h
