> From: Jakub Kicinski [mailto:jakub.kicin...@netronome.com] > > On Wed, 20 Dec 2017 09:16:01 +0900, Prashant Bhole wrote: > > > From: David Miller [mailto:da...@davemloft.net] > > > > > > From: "Prashant Bhole" <bhole_prashant...@lab.ntt.co.jp> > > > Date: Tue, 19 Dec 2017 13:45:47 +0900 > > > > > > > I tried to evaluate whether fixing return value of > > > > debugfs_create_dir() (and > > > > friends) will be useful or not because it has not been changed > > > > since very long time. Now I am not much convinced about changing this api. > > > > > > > > Important and possible error codes could be -EEXIST and -ENOMEM. > > > > Suppose -EEXIST is returned, IMO the directory shouldn't exists in > > > > the first place because it is specific to particular module. Also, > > > > there is no point in creating file in such directory, because > > > > directory owner (creator) might remove it too. This means there > > > > are less chances that api change will be useful. Please let me know your > opinion on it. > > > > > > > > If you are ok with above explanation, shall I submit v2 for this patch? > > > > > > Well, something is seriously wrong if the directory exists already. > > > > > > It could be that two netdevsim modules, independantly compiled, are > > > trying > > to > > > be loaded. > > > > > > Wouldn't it clearly be desirable to fail and not load the module in > > > that > > case? > > > > > > This is why I think ignoring debugfs errors is foolish. > > > > Right. I am planning to do following (quoting previous mail), In > > debugfs error will not be ignored in modules load. > > ----------- > > Dave, > > Thanks for comments. I will try to fix error handling in netdevsim first. > > > > Jakub, > > Let's decide with an example. The typical directory structure for > > netdevsim interface is as below: > > /sys/kernel/debug/netdevsim/sim0/bpf_bound_progs/ > > Please let me know if you are ok with following: > > > > 1) If debugfs_create_dir() fails in module_init, let's keep it fatal > > error with corrected condition: > > + if (IS_ERR_OR_NULL(nsim_ddir)) > > + return -ENOMEM; > > Ack. > > > 2) In case sim0 or bpf_bound_progs are fail to create, we need to add > > checks before creating any file in them. > > What do you mean by "check before"? Checking if creation of each file fails or > not, or something different?
For example: I will check if state->ddir is not NULL before creating files in it. if (state->ddir) { debugfs_create_u32("id", 0400, state->ddir, &prog->aux->id); debugfs_create_file("state", 0400, state->ddir, &state->state, &nsim_bpf_string_fops); debugfs_create_bool("loaded", 0400, state->ddir, &state->is_loaded); } -Prashant