| 1 | /* elision-unlock.c: Commit an elided pthread lock. |
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| 2 | Copyright (C) 2015-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include "pthreadP.h" |
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| 20 | #include "lowlevellock.h" |
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| 21 | #include "htm.h" |
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| 22 | |
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| 23 | int |
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| 24 | __lll_unlock_elision (int *lock, short *adapt_count, int pshared) |
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| 25 | { |
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| 26 | /* When the lock was free we're in a transaction. */ |
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| 27 | if (*lock == 0) |
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| 28 | __libc_tend (0); |
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| 29 | else |
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| 30 | { |
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| 31 | /* Update adapt_count in the critical section to prevent a |
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| 32 | write-after-destroy error as mentioned in BZ 20822. The |
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| 33 | following update of adapt_count has to be contained within |
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| 34 | the critical region of the fall-back lock in order to not violate |
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| 35 | the mutex destruction requirements. */ |
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| 36 | short __tmp = atomic_load_relaxed (adapt_count); |
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| 37 | if (__tmp > 0) |
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| 38 | atomic_store_relaxed (adapt_count, __tmp - 1); |
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| 39 | |
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| 40 | lll_unlock ((*lock), pshared); |
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| 41 | } |
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| 42 | return 0; |
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| 43 | } |
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| 44 | libc_hidden_def (__lll_unlock_elision) |
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| 45 | |
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