@@ -161,6 +161,7 @@ get_cached_stack (size_t *sizep, void **memp)
/* Cancellation handling is back to the default. */
result->cancelhandling = 0;
result->cancelstate = PTHREAD_CANCEL_ENABLE;
+ result->canceltype = PTHREAD_CANCEL_DEFERRED;
result->cleanup = NULL;
result->setup_failed = 0;
@@ -31,31 +31,19 @@ int
__pthread_enable_asynccancel (void)
{
struct pthread *self = THREAD_SELF;
- int oldval = THREAD_GETMEM (self, cancelhandling);
- while (1)
- {
- int newval = oldval | CANCELTYPE_BITMASK;
-
- if (newval == oldval)
- break;
-
- int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
- oldval);
- if (__glibc_likely (curval == oldval))
- {
- if (self->cancelstate == PTHREAD_CANCEL_ENABLE
- && CANCEL_CANCELED_AND_ASYNCHRONOUS (newval))
- {
- THREAD_SETMEM (self, result, PTHREAD_CANCELED);
- __do_cancel ();
- }
+ int oldval = THREAD_GETMEM (self, canceltype);
+ THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_ASYNCHRONOUS);
- break;
- }
+ int ch = THREAD_GETMEM (self, cancelhandling);
- /* Prepare the next round. */
- oldval = curval;
+ if (self->cancelstate == PTHREAD_CANCEL_ENABLE
+ && (ch & CANCELED_BITMASK)
+ && !(ch & EXITING_BITMASK)
+ && !(ch & TERMINATED_BITMASK))
+ {
+ THREAD_SETMEM (self, result, PTHREAD_CANCELED);
+ __do_cancel ();
}
return oldval;
@@ -69,25 +57,10 @@ __pthread_disable_asynccancel (int oldtype)
{
/* If asynchronous cancellation was enabled before we do not have
anything to do. */
- if (oldtype & CANCELTYPE_BITMASK)
+ if (oldtype == PTHREAD_CANCEL_ASYNCHRONOUS)
return;
struct pthread *self = THREAD_SELF;
- int newval;
-
- int oldval = THREAD_GETMEM (self, cancelhandling);
-
- while (1)
- {
- newval = oldval & ~CANCELTYPE_BITMASK;
-
- int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
- oldval);
- if (__glibc_likely (curval == oldval))
- break;
-
- /* Prepare the next round. */
- oldval = curval;
- }
+ self->canceltype = PTHREAD_CANCEL_DEFERRED;
}
libc_hidden_def (__pthread_disable_asynccancel)
@@ -31,27 +31,9 @@ ___pthread_register_cancel_defer (__pthread_unwind_buf_t *buf)
ibuf->priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
ibuf->priv.data.cleanup = THREAD_GETMEM (self, cleanup);
- int cancelhandling = THREAD_GETMEM (self, cancelhandling);
-
/* Disable asynchronous cancellation for now. */
- if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
- while (1)
- {
- int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
- cancelhandling
- & ~CANCELTYPE_BITMASK,
- cancelhandling);
- if (__glibc_likely (curval == cancelhandling))
- /* Successfully replaced the value. */
- break;
-
- /* Prepare for the next round. */
- cancelhandling = curval;
- }
-
- ibuf->priv.data.canceltype = (cancelhandling & CANCELTYPE_BITMASK
- ? PTHREAD_CANCEL_ASYNCHRONOUS
- : PTHREAD_CANCEL_DEFERRED);
+ ibuf->priv.data.canceltype = THREAD_GETMEM (self, canceltype);
+ THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_DEFERRED);
/* Store the new cleanup handler info. */
THREAD_SETMEM (self, cleanup_jmp_buf, (struct pthread_unwind_buf *) buf);
@@ -73,27 +55,9 @@ ___pthread_unregister_cancel_restore (__pthread_unwind_buf_t *buf)
THREAD_SETMEM (self, cleanup_jmp_buf, ibuf->priv.data.prev);
- int cancelhandling;
- if (ibuf->priv.data.canceltype != PTHREAD_CANCEL_DEFERRED
- && ((cancelhandling = THREAD_GETMEM (self, cancelhandling))
- & CANCELTYPE_BITMASK) == 0)
- {
- while (1)
- {
- int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
- cancelhandling
- | CANCELTYPE_BITMASK,
- cancelhandling);
- if (__glibc_likely (curval == cancelhandling))
- /* Successfully replaced the value. */
- break;
-
- /* Prepare for the next round. */
- cancelhandling = curval;
- }
-
- __pthread_testcancel ();
- }
+ THREAD_SETMEM (self, canceltype, ibuf->priv.data.canceltype);
+ if (ibuf->priv.data.canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
+ __pthread_testcancel ();
}
versioned_symbol (libc, ___pthread_unregister_cancel_restore,
__pthread_unregister_cancel_restore, GLIBC_2_34);
@@ -277,9 +277,6 @@ struct pthread
/* Flags determining processing of cancellation. */
int cancelhandling;
- /* Bit set if asynchronous cancellation mode is selected. */
-#define CANCELTYPE_BIT 1
-#define CANCELTYPE_BITMASK (0x01 << CANCELTYPE_BIT)
/* Bit set if canceled. */
#define CANCELED_BIT 3
#define CANCELED_BITMASK (0x01 << CANCELED_BIT)
@@ -292,13 +289,6 @@ struct pthread
/* Bit set if thread is supposed to change XID. */
#define SETXID_BIT 6
#define SETXID_BITMASK (0x01 << SETXID_BIT)
- /* Mask for the rest. Helps the compiler to optimize. */
-#define CANCEL_RESTMASK 0xffffff80
-
-#define CANCEL_CANCELED_AND_ASYNCHRONOUS(value) \
- (((value) & (CANCELTYPE_BITMASK | CANCELED_BITMASK \
- | EXITING_BITMASK | CANCEL_RESTMASK | TERMINATED_BITMASK)) \
- == (CANCELTYPE_BITMASK | CANCELED_BITMASK))
/* Flags. Including those copied from the thread attribute. */
int flags;
@@ -405,6 +395,10 @@ struct pthread
PTHREAD_CANCEL_DISABLE). */
unsigned char cancelstate;
+ /* Thread cancel type (PTHREAD_CANCEL_DEFERRED or
+ PTHREAD_CANCEL_ASYNCHRONOUS). */
+ unsigned char canceltype;
+
/* This member must be last. */
char end_padding[];
@@ -27,27 +27,9 @@ __libc_cleanup_push_defer (struct _pthread_cleanup_buffer *buffer)
buffer->__prev = THREAD_GETMEM (self, cleanup);
- int cancelhandling = THREAD_GETMEM (self, cancelhandling);
-
/* Disable asynchronous cancellation for now. */
- if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
- while (1)
- {
- int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
- cancelhandling
- & ~CANCELTYPE_BITMASK,
- cancelhandling);
- if (__glibc_likely (curval == cancelhandling))
- /* Successfully replaced the value. */
- break;
-
- /* Prepare for the next round. */
- cancelhandling = curval;
- }
-
- buffer->__canceltype = (cancelhandling & CANCELTYPE_BITMASK
- ? PTHREAD_CANCEL_ASYNCHRONOUS
- : PTHREAD_CANCEL_DEFERRED);
+ buffer->__canceltype = THREAD_GETMEM (self, canceltype);
+ THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_DEFERRED);
THREAD_SETMEM (self, cleanup, buffer);
}
@@ -60,26 +42,8 @@ __libc_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer)
THREAD_SETMEM (self, cleanup, buffer->__prev);
- int cancelhandling;
- if (__builtin_expect (buffer->__canceltype != PTHREAD_CANCEL_DEFERRED, 0)
- && ((cancelhandling = THREAD_GETMEM (self, cancelhandling))
- & CANCELTYPE_BITMASK) == 0)
- {
- while (1)
- {
- int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
- cancelhandling
- | CANCELTYPE_BITMASK,
- cancelhandling);
- if (__glibc_likely (curval == cancelhandling))
- /* Successfully replaced the value. */
- break;
-
- /* Prepare for the next round. */
- cancelhandling = curval;
- }
-
+ THREAD_SETMEM (self, canceltype, buffer->__canceltype);
+ if (buffer->__canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
__pthread_testcancel ();
- }
}
libc_hidden_def (__libc_cleanup_pop_restore)
@@ -53,7 +53,7 @@ sigcancel_handler (int sig, siginfo_t *si, void *ctx)
/* Set the return value. */
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
/* Make sure asynchronous cancellation is still enabled. */
- if ((ch & CANCELTYPE_BITMASK) != 0)
+ if (self->canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
__do_cancel ();
}
@@ -104,7 +104,7 @@ __pthread_cancel (pthread_t th)
#endif
THREAD_SETMEM (pd, result, PTHREAD_CANCELED);
- if ((oldch & CANCELTYPE_BITMASK) != 0)
+ if (pd->canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
__do_cancel ();
return 0;
}
@@ -29,43 +29,11 @@ __pthread_setcanceltype (int type, int *oldtype)
volatile struct pthread *self = THREAD_SELF;
- int oldval = THREAD_GETMEM (self, cancelhandling);
- while (1)
- {
- int newval = (type == PTHREAD_CANCEL_ASYNCHRONOUS
- ? oldval | CANCELTYPE_BITMASK
- : oldval & ~CANCELTYPE_BITMASK);
-
- /* Store the old value. */
- if (oldtype != NULL)
- *oldtype = ((oldval & CANCELTYPE_BITMASK)
- ? PTHREAD_CANCEL_ASYNCHRONOUS : PTHREAD_CANCEL_DEFERRED);
-
- /* Avoid doing unnecessary work. The atomic operation can
- potentially be expensive if the memory has to be locked and
- remote cache lines have to be invalidated. */
- if (oldval == newval)
- break;
-
- /* Update the cancel handling word. This has to be done
- atomically since other bits could be modified as well. */
- int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
- oldval);
- if (__glibc_likely (curval == oldval))
- {
- if (self->cancelstate == PTHREAD_CANCEL_ENABLE
- && CANCEL_CANCELED_AND_ASYNCHRONOUS (newval))
- {
- THREAD_SETMEM (self, result, PTHREAD_CANCELED);
- __do_cancel ();
- }
-
- break;
- }
-
- /* Prepare for the next round. */
- oldval = curval;
- }
+ if (oldtype != NULL)
+ *oldtype = self->canceltype;
+ self->canceltype = type;
+ if (type == PTHREAD_CANCEL_ASYNCHRONOUS)
+ __pthread_testcancel ();
return 0;
}