From 8834dcf47e8543b92e072706d3a5621762bfa106 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 17 Mar 2020 15:17:20 +0100 Subject: [PATCH] lockable: add QEMU_MAKE_LOCKABLE_NONNULL This will be needed for lock guards, because if the lock is NULL the dummy for loop of the lock guard never runs. This can cause confusion and dummy warnings in the compiler, but even if it did not, aborting with a NULL pointer dereference is a less surprising behavior. Signed-off-by: Paolo Bonzini --- include/qemu/lockable.h | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/include/qemu/lockable.h b/include/qemu/lockable.h index 84ea794bcf..313d4d9b73 100644 --- a/include/qemu/lockable.h +++ b/include/qemu/lockable.h @@ -65,7 +65,7 @@ qemu_make_lockable(void *x, QemuLockable *lockable) * In C++ it would be different, but then C++ wouldn't need QemuLockable * either... */ -#define QEMU_MAKE_LOCKABLE_(x) qemu_make_lockable((x), &(QemuLockable) { \ +#define QEMU_MAKE_LOCKABLE_(x) (&(QemuLockable) { \ .object = (x), \ .lock = QEMU_LOCK_FUNC(x), \ .unlock = QEMU_UNLOCK_FUNC(x), \ @@ -76,9 +76,22 @@ qemu_make_lockable(void *x, QemuLockable *lockable) * @x: a lock object (currently one of QemuMutex, CoMutex, QemuSpin). * * Returns a QemuLockable object that can be passed around - * to a function that can operate with locks of any kind. + * to a function that can operate with locks of any kind, or + * NULL if @x is %NULL. */ #define QEMU_MAKE_LOCKABLE(x) \ + QEMU_GENERIC(x, \ + (QemuLockable *, (x)), \ + qemu_make_lockable((x), QEMU_MAKE_LOCKABLE_(x))) + +/* QEMU_MAKE_LOCKABLE_NONNULL - Make a polymorphic QemuLockable + * + * @x: a lock object (currently one of QemuMutex, CoMutex, QemuSpin). + * + * Returns a QemuLockable object that can be passed around + * to a function that can operate with locks of any kind. + */ +#define QEMU_MAKE_LOCKABLE_NONNULL(x) \ QEMU_GENERIC(x, \ (QemuLockable *, (x)), \ QEMU_MAKE_LOCKABLE_(x)) -- 2.39.2