Confused about which branch to patch against

[Gustavo A. R. Silva]

Hi,

On 9/22/20 21:08, James Browning wrote:
> Hi all,
> 
> After reading through the kernel documentation about submitting pathces,
> and reading through the kernel newbies guide to submitting patches, I
> still have some confusion.
> 
> Should I be doing all of my patching against linux-next as opposed to
> the mainline tree? I tried submitting a patch to some typos I found on
> the mainline tree, but they were rejected because they had already been
> fixed in linux-next. 

Yes; bleeding edge development happens in linux-next. Just notice that
there is a new linux-next everyday. This is, linux-next is merely a daily
merge of all the individual development '-next' trees.

Don't get discouraged if your patches are not applied because someone
else already sent a patch to fix the same issue. That certainly happens
every now and then.

I suggest you to start your journey by addressing issues in staging, first.
Especially, typos and coding style issues. Also, this is a great resource:

https://kernelnewbies.org/Outreachyfirstpatch

Read it thoroughly. :)

> I guess I dont really understand what patches become part of the next
> mainline rc-x tree, and which patches become part of linux-next (which
> from what I understand, doesn't get merged until the next merge window when the current kernel version is finished being stabalized).

I encourage you to enroll in this course:

https://training.linuxfoundation.org/training/a-beginners-guide-to-linux-kernel-development-lfd103/

It's free and there is a section in the beginning that explains all
about the differences between mainline, -rc, linux-next and stable
trees and how they relate to each other.

> Also, if I patch something in the linux-next tree, do I need to specify
> which tree it is when I send the patch the maintainers?

Not necessarily. However, some people explicitly ask you to add 'next' to the
subject line. The networking people, in particular.

In any case, you'll be safe by adding [next] to the subject line, as follows:

[PATCH][next] subject

and the maintainers will know that's for their -next tree. Just make sure you
CC all the file maintainers.

I hope this helps.

--
Gustavo