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authorMike Crowe <mac@mcrowe.com>2019-06-21 14:53:40 +0000
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2019-07-12 13:36:23 +0000
commit99d01ffcc386d1bfb681fb0684fcf6a6a996beb3 (patch)
tree166e14d240825fdab7863e955dcbc9c8413c5781 /sysdeps/unix/sysv/linux/lowlevellock-futex.h
parenta008c76b56e4f958cf5a0d6f67d29fade89421b7 (diff)
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nptl: Add clockid parameter to futex timed wait calls
In preparation for adding POSIX clockwait variants of timedwait functions,
add a clockid_t parameter to futex_abstimed_wait functions and pass
CLOCK_REALTIME from all callers for the time being.

Replace lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset
which takes a clockid_t parameter rather than the magic clockbit.

	* sysdeps/nptl/lowlevellock-futex.h,
	sysdeps/unix/sysv/linux/lowlevellock-futex.h: Replace
	lll_futex_timed_wait_bitset with lll_futex_clock_wait_bitset that
	takes a clockid rather than a special clockbit.
	* sysdeps/nptl/lowlevellock-futex.h: Add
	lll_futex_supported_clockid so that client functions can check
	whether their clockid parameter is valid even if they don't
	ultimately end up calling lll_futex_clock_wait_bitset.
	* sysdeps/nptl/futex-internal.h,
	sysdeps/unix/sysv/linux/futex-internal.h
	(futex_abstimed_wait, futex_abstimed_wait_cancelable): Add
	clockid_t parameter to indicate which clock the absolute time
	passed should be measured against. Pass that clockid onto
	lll_futex_clock_wait_bitset. Add invalid clock as reason for
	returning -EINVAL.
	* sysdeps/nptl/futex-internal.h,
	sysdeps/unix/sysv/linux/futex-internal.h: Introduce
	futex_abstimed_supported_clockid so that client functions can check
	whether their clockid parameter is valid even if they don't
	ultimately end up calling futex_abstimed_wait.
	* nptl/pthread_cond_wait.c (__pthread_cond_wait_common): Remove
	code to calculate relative timeout for
	__PTHREAD_COND_CLOCK_MONOTONIC_MASK and just pass CLOCK_MONOTONIC
	or CLOCK_REALTIME as required to futex_abstimed_wait_cancelable.
	* nptl/pthread_rwlock_common (__pthread_rwlock_rdlock_full)
	(__pthread_wrlock_full), nptl/sem_waitcommon (do_futex_wait): Pass
	additional CLOCK_REALTIME to futex_abstimed_wait_cancelable.
	* nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock):
	Switch to lll_futex_clock_wait_bitset and pass CLOCK_REALTIME

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/unix/sysv/linux/lowlevellock-futex.h')
-rw-r--r--sysdeps/unix/sysv/linux/lowlevellock-futex.h32
1 files changed, 26 insertions, 6 deletions
diff --git a/sysdeps/unix/sysv/linux/lowlevellock-futex.h b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
index 030a14b8dc..cfa796be2b 100644
--- a/sysdeps/unix/sysv/linux/lowlevellock-futex.h
+++ b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
@@ -82,12 +82,32 @@
 		     __lll_private_flag (FUTEX_WAIT, private),  \
 		     val, timeout)
 
-#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
-  lll_futex_syscall (6, futexp,                                         \
-		     __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \
-					 private),                      \
-		     val, timeout, NULL /* Unused.  */,                 \
-		     FUTEX_BITSET_MATCH_ANY)
+/* Verify whether the supplied clockid is supported by
+   lll_futex_clock_wait_bitset.  */
+#define lll_futex_supported_clockid(clockid)			\
+  ((clockid) == CLOCK_REALTIME || (clockid) == CLOCK_MONOTONIC)
+
+/* The kernel currently only supports CLOCK_MONOTONIC or
+   CLOCK_REALTIME timeouts for FUTEX_WAIT_BITSET.  We could attempt to
+   convert others here but currently do not.  */
+#define lll_futex_clock_wait_bitset(futexp, val, clockid, timeout, private) \
+  ({									\
+    long int __ret;							\
+    if (lll_futex_supported_clockid (clockid))                          \
+      {                                                                 \
+        const unsigned int clockbit =                                   \
+          (clockid == CLOCK_REALTIME) ? FUTEX_CLOCK_REALTIME : 0;       \
+        const int op =                                                  \
+          __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private);   \
+                                                                        \
+        __ret = lll_futex_syscall (6, futexp, op, val,                  \
+                                   timeout, NULL /* Unused.  */,	\
+                                   FUTEX_BITSET_MATCH_ANY);		\
+      }                                                                 \
+    else                                                                \
+      __ret = -EINVAL;							\
+    __ret;								\
+  })
 
 #define lll_futex_wake(futexp, nr, private)                             \
   lll_futex_syscall (4, futexp,                                         \