commit 78155888b8f44478dd78b9af2f1e0eb255e7dfb4
author Jerome Forissier <jerome@forissier.org> Fri Sep 27 13:33:59 2019 +0200
committer Jérôme Forissier <jerome@forissier.org> Wed Oct 02 17:06:15 2019 +0200
tree 7386af03050a0db495ab04f3f7b7b83af8cb4968
parent a2087649ca68f259e980594f536ea3ff19c4bbe3

core: tadb.c: get rid of atomic reference counting

This commit changes the way the tadb_db global variable is protected
against concurrent access on creation and deletion. Instead of using an
atomic reference counter (struct refcount) and a mutex, only the mutex
is used and taken unconditionally. The reference count becomes a global
integer protected by the same mutex.

Using a struct refcount was apparently an optimization to avoid taking
the lock unless actual creation or deletion of the tadb_db was needed.
Unfortunately this implementation was causing occasional crashes of the
TEE core (easily reproducible on HiKey running 'xtest 1013' in a loop).
The new implementation is simpler and appears to be rock solid with no
measurable difference in performance.

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>