lockable: add QemuLockable

QemuLockable is a polymorphic lock type that takes an object and
knows which function to use for locking and unlocking.  The
implementation could use C11 _Generic, but since the support is
not very widespread I am instead using __builtin_choose_expr and
__builtin_types_compatible_p, which are already used by
include/qemu/atomic.h.

QemuLockable can be used to implement lock guards, or to pass around
a lock in such a way that a function can release it and re-acquire it.
The next patch will do this for CoQueue.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20180203153935.8056-3-pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index 9bd7a834ba..5923849cdd 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -19,6 +19,7 @@ typedef struct BusClass BusClass;
 typedef struct BusState BusState;
 typedef struct Chardev Chardev;
 typedef struct CompatProperty CompatProperty;
+typedef struct CoMutex CoMutex;
 typedef struct CPUAddressSpace CPUAddressSpace;
 typedef struct CPUState CPUState;
 typedef struct DeviceListener DeviceListener;
@@ -86,9 +87,12 @@ typedef struct QEMUBH QEMUBH;
 typedef struct QemuConsole QemuConsole;
 typedef struct QemuDmaBuf QemuDmaBuf;
 typedef struct QEMUFile QEMUFile;
+typedef struct QemuLockable QemuLockable;
+typedef struct QemuMutex QemuMutex;
 typedef struct QemuOpt QemuOpt;
 typedef struct QemuOpts QemuOpts;
 typedef struct QemuOptsList QemuOptsList;
+typedef struct QemuSpin QemuSpin;
 typedef struct QEMUSGList QEMUSGList;
 typedef struct QEMUTimer QEMUTimer;
 typedef struct QEMUTimerListGroup QEMUTimerListGroup;