Linus Torvalds: Linux-2.4.x patch submission policy

Subject: Linux-2.4.x patch submission policy
Date: 6 Jan 2001 10:17:02 -0800
From: torvalds@transmeta.com (Linus Torvalds)
To: linux-kernel@vger.kernel.org


I thought I'd mention the policy for 2.4.x patches so that nobody
gets confused about these things.  In some cases people seem to
think that "since 2.4.x is out now, we can relax, go party, and
generally goof off".

Not so.

The linux kernel has had an interesting release pattern: usually the
.0 release was actually fairly good (there's almost always
_something_ stupid, but on the whole not really horrible).  And
every single time so far, .1 has been worse.  It usually takes until
something like .5 until it has caught up and surpassed the stability
of .0 again.

Why? Because there are a lot of pent-up patches waiting for
inclusion, that didn't get through the "we need to get a release
out, that patch can wait" filter.  So early on in the stable tree,
some of those patches make it.  And it turns out to be a bad idea.

In an effort to avoid this mess this time, I have two guidelines:

- I've basically thrown away all patches sent to me so far, and I
will continue to do so at least over the weekend. I'm not going to
bother thinking about patches for a few days.

- In order for a patch to be accepted, it needs to be accompanied by
some pretty strong arguments for the fact that not only is it
really fixing bugs, but that those bugs are _serious_ and can cause
real problems.

Obviously, the size of the patch matters too: if you can make an
obvious fix in 5 lines, do it.  Don't try to make a clean fix that
fixes the problem the clever way in 150 lines.

In short, releasing 2.4.0 does not open up the floor to just about
anything.  In fact, to some degree it will probably make patches
_less_ likely to be accepted than before, at least for a while.  I
want to be absolutely convicned that the basic 2.4.x infrastructure
is solid as a rock before starting to accept more involved patches.

Right now my ChangeLog looks like this:

 - Don't drop a megabyte off the old-style memory size detection
 - remember to UnlockPage() in ramfs_writepage()
 - 3c59x driver update from Andrew Morton

The first two are true one-liners that have already bitten some
people (not what I'd call a showstopper, but trivially fixable stuff
that are just thinkos).  The third one looks like a real fix for
some rather common hardware that could do bad things without it.

Now, I'm sure that ChangeLog will grow.  There's the apparent fbcon
bug with MTRR handling that looks like a prime candidate already,
and I'll have people asking me for many many more.  But basically
what I'm asking people for is that before you send me a patch, ask
yourself whether it absolutely HAS to happen now, or whether it
could wait another month.

Another way of putting it: if you have a patch, ask yourself what
would happen if it got left off the next
RedHat/SuSE/Debian/Turbo/whatever distribution CD.  Would it really
be a big problem? If not, then I'd rather spend the time _really_
beating on the patches that _would_ be a big issue.  Things like
security (_especially_ remote attacks), outright crashes, or just
totally unusable systems because it can't see the harddisk.

We'll all be happier if my ChangeLog is short and sweet, and if a
2.4.1 (tomorrow, in a week, in two, in a month, depending on what
comes up) actually ends up being _better_ than 2.4.0.  That would be
a good new tradition to start.

And before you even bother asking about 2.5.x: it won't be opened
until I feel happy to pass on 2.4.x to somebody else (hopefully Alan
Cox doesn't feel burnt out and wants to continue to carry the torch
and feels ok with leaving 2.2.x behind by then).

Historically, that's been at least a few months.  In the 2.2.x
series, 2.3.0 was the same as 2.2.8 with just the version changed -
and it came out in May, almost four months after 2.2.0.  In the
2.0.x series, 2.1.x was based off 2.0.21, four and a half months
after 2.0.0.

Yes, I know this is boring, and all I'm asking is for people to not
make it any harder for me than they have to.  Think twice before
sending me a patch, and when you _do_ send me a patch, try to think
like a release manager and explain to me why the patch really makes
sense to apply now.

In short, I'm hoping for a fairly boring next few months. The more
boring, the better.

                Thanks,

                Linus