Question regarding upstreaming patches written by multiple people and checkpatch

[Joseph Bisch]

Hi,

I am trying to upstream a patch set that wasn't written by me. The
original patch has a lot of warnings and errors reported by
checkpatch. Someone else corrected some of those with another patch
and I added on a third patch correcting the rest of the warnings and
errors that I thought were appropriate to fix.

When checkpatch is run on the file that the patches affect, the output
looks okay to me, but when I run checkpatch on the patches themselves,
the patches still have the same errors and warnings, because I made my
changes in a separate patch.

So is it okay to have checkpatch errors/warnings for individual
patches as long as the patch series as a whole is reasonably
checkpatch clean or should I be amending my changes to the original
commit and squashing the other cleanup patch into the first patch, so
that I am left with one patch that passes checkpatch?

If I should be squashing the patches into a single patch, how do I
handle the signed-off-by lines as each of the three patches is
currently signed off by the respective author of the patch? Obviously
I can sign off on the squashed patch for myself. Do I just send it to
the mailing list with just my sign off and CC the authors, so that
they can sign off on it? From what I've been told, it sounds like
CC'ing the authors and having them reply with their sign off is the
appropriate way to handle this, but I want to make sure before I start
mailing out patches, and this isn't something that I have been able to
find an answer to.

Cheers,
Joseph