Re: [dpdk-dev] [PATCH] eal: Fixes VFIO/sysfs race condition

[David Marchand <david.marchand@redhat.com>]

On Mon, Apr 6, 2020 at 9:15 PM Haeuptle, Michael
<michael.haeuptle@hpe.com> wrote:
> This is my first submission... how do I get the fixes reference?

I recommend reading: https://doc.dpdk.org/guides/contributing/patches.html
But let me help you this time.

For the missing Fixes: tag, we want to get the sha1 of the commit that
first exhibited the issue.
For this you must either use git bisect (not always possible) or go
back in the git history and find the culprit commit.
git log -p --follow and git blame can help identify it (just be
cautious and skip purely cosmetic changes if any).

In your case, I *think* the commit is
340b7bb8d583661369a9491ade63fe2407e85267, since it introduced the
vfio_open_group_fd() function and the check on its return value.
I did not see changes between this commit and origin/master wrt to
vfio_open_group_fd() return values.
It might have been older than this, the vfio maintainer can help confirm.
Anatoly, can you double check :-) ?


For the formatting of the Fixes: tag, you have a git macro in
https://doc.dpdk.org/guides/contributing/patches.html#commit-messages-body
Which then gives:
$ git fixline 340b7bb8d58
Fixes: 340b7bb8d583 ("vfio: extend data structure for multi container")

>
> Back porting it to 19.11 would be great. This issue shows up in SPDK 20.01, which uses 19.11.

For the criterias on what should be backported:
https://doc.dpdk.org/guides/contributing/stable.html#what-changes-should-be-backported.

You can annotate a patch with a version, but it will be informational only.
What is important is to Cc: stable@dpdk.org so that stable maintainers
see this fix and consider it for backport in the currently maintained
branches (atm 18.11 and 19.11).
The Fixes: line already gives an idea of which branches are concerned.
The stable maintainers have scripts to catch fixes of interest for
them (+ those scripts also check if a change is a fix of a previous
fix that got backported itself).

Here, if the above Fixes: is correct, it means this backport is a
candidate to backport to 18.11 and 19.11.


-- 
David Marchand