Comment 19 for bug 1910866

OK, the fix will be in next 5.8 update:
commit f62ddacc4cb141b86ed647f9dd9eeb7653b0cc43
Author: Keith Busch <email address hidden>
Date: Fri Oct 30 10:28:54 2020 -0700

    Revert "nvme-pci: remove last_sq_tail"

    BugLink: https://bugs.launchpad.net/bugs/1908555

    [ Upstream commit 38210800bf66d7302da1bb5b624ad68638da1562 ]

    Multiple CPUs may be mapped to the same hctx, allowing mulitple
    submission contexts to attempt commit_rqs(). We need to verify we're
    not writing the same doorbell value multiple times since that's a spec
    violation.

    Revert commit 54b2fcee1db041a83b52b51752dade6090cf952f.

    Link: https://bugzilla.redhat.com/show_bug.cgi?id=1878596
    Reported-by: "B.L. Jones" <email address hidden>
    Signed-off-by: Keith Busch <email address hidden>
    Signed-off-by: Sasha Levin <email address hidden>
    Signed-off-by: Kamal Mostafa <email address hidden>
    Signed-off-by: Ian May <email address hidden>