Re: mm snapshot broken-out-2007-01-26-00-36.tar.gz uploaded

From: Valdis . Kletnieks
Date: Mon Jan 29 2007 - 01:46:20 EST


On Sun, 28 Jan 2007 23:08:17 MST, Eric W. Biederman said:
> Valdis.Kletnieks@xxxxxx writes:

> Does it find sys? If so perhaps I should do something even more significant.
> I guess if I get many complaints about this I will figure out how to print
> out an appropriate error message.

It found sys, and then the second iteration in in xlate_proc_name it failed
to find net because the de->subdir for sys/net wasn't set.

> > What's the intended semantics of create_proc_entry and xlate_proc_name in
> > this new regime of no subdir pointers? Or am I just (yet again) one of the
> > first to trip over a bug?
>
> It is supposed to fail in this instance. If you want something under /proc/sys
> you are supposed to use register_sysctl like everyone else. If it's not a
> sysctl it should not show up under /proc/sys.

Wasn't my code originally - I think the original author thought that since
all the *other* config stuff for ipv4 was down under /proc/sys/net/ipv4, this
one should be as well because that's where sysadmins would look for it, and
wasn't thinking so much about whether it was a sysctl or not.

> I'm glad to see my cleanup uncovering more bugs, I'm sorry you were the one
> who had to find it. I will you well fixing your out of tree ipfilter module.

It's easy enough to move the entry under /proc/net or someplace instead.

What's the current advice on what kernel interface to use for this scenario:

In userspace, we do something like this:

(while read foo; do echo $foo > /proc/my_file; done) < /etc/bunch_of_lines

and we want to catch, parse, and save each line as it enters the kernel, and
we end up with several dozen entries saved.

If we do a 'cat /proc/my_file', we iterate across the list of saved lines
and dump them all out.


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