86956e7076
It was pointed out during an unrelated patch review that locks should not be open coded - i.e., writing the algorithm of a standard lock in a function instead of using a lock from the standard library. The setting and testing of a busy flag and sleeping on a wait_event is the same thing a lock does. The open coded locks are invisible to lockdep, so potential locking problems are not detected. This patch removes the open coded locks used during VFIO_GROUP_NOTIFY_SET_KVM notification. The busy flag and wait queue were introduced to resolve a possible circular locking dependency reported by lockdep when starting a secure execution guest configured with AP adapters and domains. Reversing the order in which the kvm->lock mutex and matrix_dev->lock mutex are locked resolves the issue reported by lockdep, thus enabling the removal of the open coded locks. Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> Acked-by: Halil Pasic <pasic@linux.ibm.com> Link: https://lore.kernel.org/r/20210823212047.1476436-3-akrowiak@linux.ibm.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.