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gh-154707: Replace PyThread_type_lock with PyMutex in bufferedio.c #154708

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gh-154707: Replace PyThread_type_lock with PyMutex in bufferedio.c #154708

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974d879
Replace `PyThread_type_lock` with `PyMutex` in `bufferedio.c`
ByteFlowing1337 Jul 25, 2026
2b75a5b
Fix the timeout value
ByteFlowing1337 Jul 26, 2026
b1a627e
Fix uninitialized warning
ByteFlowing1337 Jul 26, 2026
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26 changes: 9 additions & 17 deletions Modules/_io/bufferedio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -254,7 +254,7 @@ typedef struct {
isn't ready for writing. */
Py_off_t write_end;

PyThread_type_lock lock;
PyMutex mutex;
volatile unsigned long owner;

Py_ssize_t buffer_size;
Expand Down Expand Up @@ -304,16 +304,18 @@ _enter_buffered_busy(buffered *self)
PyInterpreterState *interp = _PyInterpreterState_GET();
relax_locking = _Py_IsInterpreterFinalizing(interp);
Py_BEGIN_ALLOW_THREADS
if (!relax_locking)
st = PyThread_acquire_lock(self->lock, 1);
if (!relax_locking) {
PyMutex_Lock(&self->mutex);
st = PY_LOCK_ACQUIRED;
}
else {
/* When finalizing, we don't want a deadlock to happen with daemon
* threads abruptly shut down while they owned the lock.
* Therefore, only wait for a grace period (1 s.).
* Note that non-daemon threads have already exited here, so this
* shouldn't affect carefully written threaded I/O code.
*/
st = PyThread_acquire_lock_timed(self->lock, (PY_TIMEOUT_T)1e6, 0);
st = _PyMutex_LockTimed(&self->mutex, (PyTime_t)1e9, 0);
}
Py_END_ALLOW_THREADS
if (relax_locking && st != PY_LOCK_ACQUIRED) {
Expand All @@ -327,14 +329,14 @@ _enter_buffered_busy(buffered *self)
}

#define ENTER_BUFFERED(self) \
( (PyThread_acquire_lock(self->lock, 0) ? \
( (_PyMutex_LockTimed(&self->mutex, (PyTime_t)0, 0) ? \
1 : _enter_buffered_busy(self)) \
&& (self->owner = PyThread_get_thread_ident(), 1) )

#define LEAVE_BUFFERED(self) \
do { \
self->owner = 0; \
PyThread_release_lock(self->lock); \
PyMutex_Unlock(&self->mutex); \
} while(0);

#define CHECK_INITIALIZED(self) \
Expand Down Expand Up @@ -436,10 +438,6 @@ buffered_dealloc(PyObject *op)
PyMem_Free(self->buffer);
self->buffer = NULL;
}
if (self->lock) {
PyThread_free_lock(self->lock);
self->lock = NULL;
}
(void)buffered_clear(op);
tp->tp_free(self);
Py_DECREF(tp);
Expand Down Expand Up @@ -850,13 +848,7 @@ _buffered_init(buffered *self)
PyErr_NoMemory();
return -1;
}
if (self->lock)
PyThread_free_lock(self->lock);
self->lock = PyThread_allocate_lock();
if (self->lock == NULL) {
PyErr_SetString(PyExc_RuntimeError, "can't allocate read lock");
return -1;
}
self->mutex = (PyMutex){0};
self->owner = 0;
/* Find out whether buffer_size is a power of 2 */
/* XXX is this optimization useful? */
Expand Down
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