On Tue, Mar 31, 2020 at 08:32:17AM -0400, Sasha Levin wrote: > Hi all, > > I wanted to share a resource I've been using to help me with doing > backports to various stable kernels. > > In the Stable Kernel world, when we need to backport a patch, we'd > rather take any relevant dependencies to make the patch work cleanly on > an older kernel, rather than modifying the patch and diverging from > upstream. > > This raises an interesting problem: how do we figure out which other > patches might be "interesting" to look at? git-blame is a great tool, > but it takes a while to go through the history of a patch, and given the > volume of patches we need to look at, it just isn't enough. > > So here's a tool in the form of a git repo that can help point out these > interesting patches: > > https://git.kernel.org/pub/scm/linux/kernel/git/sashal/deps.git/ > > How does it work, you might ask? It's actually quite simple: Each > directory represents a kernel version which we'll call K, and each file > inside that directory is named after an upstream commit we'll call C, > and it's content are the list of commits one would need to apply on top > of kernel K to "reach" commit C. > > For example, let's say we want to apply: > > f8788d86ab28 ("Linux 5.6-rc3") > > On top of the v5.5 kernel tree. All we need to do is: > > $ cat v5.5/f8788d86ab28f61f7b46eb6be375f8a726783636 > f8788d86ab28 ("Linux 5.6-rc3") > 11a48a5a18c6 ("Linux 5.6-rc2") > bb6d3fb354c5 ("Linux 5.6-rc1") > > If you don't feel like cloning the repo (which contains quite a few > files), you can also use kernel.org's web interface in a script that > might look something like this: > > #!/bin/bash > curl https://git.kernel.org/pub/scm/linux/kernel/git/sashal/deps.git/plain/$1/$2 > > And then simply: > > $ ./deps.sh v5.5 f8788d86ab28f61f7b46eb6be375f8a726783636 > f8788d86ab28 ("Linux 5.6-rc3") > 11a48a5a18c6 ("Linux 5.6-rc2") > bb6d3fb354c5 ("Linux 5.6-rc1") > > Caveats: > > - Each file is limited to 50 entries. I feel that at that point it > stops being useful. > - Each file stops if a merge commit is hit. > - I might have bugs in my scripts and some entries are broken, please > report those if you see them. This is really cool, thanks for posting this, and for doing this work. greg k-h
