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| author | Mike Frysinger <vapier@gentoo.org> | 2015-07-28 02:19:49 -0400 |
|---|---|---|
| committer | Mike Frysinger <vapier@gentoo.org> | 2015-07-28 05:03:27 -0400 |
| commit | 978908245b2c0f759100708a9966649f7b273664 (patch) | |
| tree | a2a8dacbc615d6051fe0d07c4ec3afdd156dec74 | |
| parent | 8a4e5cc6574a419d5724bef6be98d705d58db48d (diff) | |
| download | glibc-978908245b2c0f759100708a9966649f7b273664.tar.gz glibc-978908245b2c0f759100708a9966649f7b273664.tar.xz glibc-978908245b2c0f759100708a9966649f7b273664.zip | |
ia64: atomic.h: fix atomic_exchange_and_add 64bit handling
Way back in 2005 the atomic_exchange_and_add function was cleaned up to avoid the explicit size checking and instead let gcc handle things itself. Unfortunately that change ended up leaving beyond a cast to int, even when the incoming value was a long. This has flown under the radar for a long time due to the function not being heavily used in the tree (especially as a full 64bit field), but a recent change to semaphores made some nptl tests fail reliably. This is due to the code packing two 32bit values into one 64bit variable (where the high 32bits contained the number of waiters), and then the whole variable being atomically updated between threads. On ia64, that meant we never atomically updated the count, so sometimes the sem_post would not wake up the waiters. (cherry picked from commit cf31a2c79957936b60de34ea1e718e892baf669c)
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | sysdeps/ia64/bits/atomic.h | 4 |
2 files changed, 6 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog index 68ee6c3402..61e667158d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2015-07-27 Mike Frysinger <vapier@gentoo.org> + + * sysdeps/ia64/bits/atomic.h (atomic_exchange_and_add): Define + directly in terms of __sync_fetch_and_add and delete (int) cast. + 2015-02-22 Paul Pluzhnikov <ppluzhnikov@google.com> [BZ #17269] diff --git a/sysdeps/ia64/bits/atomic.h b/sysdeps/ia64/bits/atomic.h index 0e9dfc7174..4c2b54094c 100644 --- a/sysdeps/ia64/bits/atomic.h +++ b/sysdeps/ia64/bits/atomic.h @@ -82,9 +82,7 @@ typedef uintmax_t uatomic_max_t; (__sync_synchronize (), __sync_lock_test_and_set (mem, value)) #define atomic_exchange_and_add(mem, value) \ - ({ __typeof (*mem) __result; \ - __result = __sync_fetch_and_add ((mem), (int) (value)); \ - __result; }) + __sync_fetch_and_add ((mem), (value)) #define atomic_decrement_if_positive(mem) \ ({ __typeof (*mem) __oldval, __val; \ |