This is both more and less complicated than our expansion
using __builtin_choose_expr and __builtin_types_compatible_p.
The expansion through QEMU_MAKE_LOCKABLE_ doesn't work because
we're not emumerating all of the types within the same _Generic,
which results in errors about unhandled cases. We must also
handle void* explicitly, so that the NULL constant can be used.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210614233143.1221879-7-richard.henderson@linaro.org>
- __COUNTER__ doesn't work with ## concat
- replaced ## with glue() macro so __COUNTER__ is evaluated
Fixes: 3284c3ddc4
Signed-off-by: Daniel Brodsky <dnbrdsky@gmail.com>
Message-id: 20200404042108.389635-2-dnbrdsky@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The polymorphic locking macros don't support QemuRecMutex yet. Add it
so that lock guards can be used with QemuRecMutex.
Convert TCG plugins functions that benefit from these macros. Manual
qemu_rec_mutex_lock/unlock() callers are left unmodified in cases where
clarity would not improve by switching to the macros.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch introduces two lock guard macros that automatically unlock a
lock object (QemuMutex and others):
void f(void) {
QEMU_LOCK_GUARD(&mutex);
if (!may_fail()) {
return; /* automatically unlocks mutex */
}
...
}
and:
WITH_QEMU_LOCK_GUARD(&mutex) {
if (!may_fail()) {
return; /* automatically unlocks mutex */
}
}
/* automatically unlocks mutex here */
...
Convert qemu-timer.c functions that benefit from these macros as an
example. Manual qemu_mutex_lock/unlock() callers are left unmodified in
cases where clarity would not improve by switching to the macros.
Many other QemuMutex users remain in the codebase that might benefit
from lock guards. Over time they can be converted, if that is
desirable.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
[Use QEMU_MAKE_LOCKABLE_NONNULL. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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 <pbonzini@redhat.com>
Current GCC has an optimization bug when compiling with ASAN.
See also GCC bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84307
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180215212552.26997-3-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
