/* * Copyright (C) 2010, 2015 Mathieu Desnoyers * * membarrier system call * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include /* * Bitmask made from a "or" of all commands within enum membarrier_cmd, * except MEMBARRIER_CMD_QUERY. */ #define MEMBARRIER_CMD_BITMASK (MEMBARRIER_CMD_SHARED) /** * sys_membarrier - issue memory barriers on a set of threads * @cmd: Takes command values defined in enum membarrier_cmd. * @flags: Currently needs to be 0. For future extensions. * * If this system call is not implemented, -ENOSYS is returned. If the * command specified does not exist, or if the command argument is invalid, * this system call returns -EINVAL. For a given command, with flags argument * set to 0, this system call is guaranteed to always return the same value * until reboot. * * All memory accesses performed in program order from each targeted thread * is guaranteed to be ordered with respect to sys_membarrier(). If we use * the semantic "barrier()" to represent a compiler barrier forcing memory * accesses to be performed in program order across the barrier, and * smp_mb() to represent explicit memory barriers forcing full memory * ordering across the barrier, we have the following ordering table for * each pair of barrier(), sys_membarrier() and smp_mb(): * * The pair ordering is detailed as (O: ordered, X: not ordered): * * barrier() smp_mb() sys_membarrier() * barrier() X X O * smp_mb() X O O * sys_membarrier() O O O */ SYSCALL_DEFINE2(membarrier, int, cmd, int, flags) { if (unlikely(flags)) return -EINVAL; switch (cmd) { case MEMBARRIER_CMD_QUERY: return MEMBARRIER_CMD_BITMASK; case MEMBARRIER_CMD_SHARED: if (num_online_cpus() > 1) synchronize_sched(); return 0; default: return -EINVAL; } } und/isa/cs423x/cs4236.c'>
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authorFeng <fgao@ikuai8.com>2017-01-20 21:40:43 +0800
committerPablo Neira Ayuso <pablo@netfilter.org>2017-02-02 14:30:19 +0100
commit10435c1192d06bdb0bac7666452d8219d7e7c477 (patch)
tree93b76419142fe17b1d162d062c663297a3e8a965 /sound/isa/cs423x/cs4236.c
parent1a28ad74ebd8f9d3c7eae0d781f72a6d30545e17 (diff)
netfilter: nf_tables: Eliminate duplicated code in nf_tables_table_enable()
If something fails in nf_tables_table_enable(), it unregisters the chains. But the rollback code is the same as nf_tables_table_disable() almostly, except there is one counter check. Now create one wrapper function to eliminate the duplicated codes. Signed-off-by: Feng <fgao@ikuai8.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'sound/isa/cs423x/cs4236.c')