/* * Queued read/write locks * * 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. * * (C) Copyright 2013-2014 Hewlett-Packard Development Company, L.P. * * Authors: Waiman Long */ #include #include #include #include #include #include /* * This internal data structure is used for optimizing access to some of * the subfields within the atomic_t cnts. */ struct __qrwlock { union { atomic_t cnts; struct { #ifdef __LITTLE_ENDIAN u8 wmode; /* Writer mode */ u8 rcnts[3]; /* Reader counts */ #else u8 rcnts[3]; /* Reader counts */ u8 wmode; /* Writer mode */ #endif }; }; arch_spinlock_t lock; }; /** * rspin_until_writer_unlock - inc reader count & spin until writer is gone * @lock : Pointer to queue rwlock structure * @writer: Current queue rwlock writer status byte * * In interrupt context or at the head of the queue, the reader will just * increment the reader count & wait until the writer releases the lock. */ static __always_inline void rspin_until_writer_unlock(struct qrwlock *lock, u32 cnts) { while ((cnts & _QW_WMASK) == _QW_LOCKED) { cpu_relax(); cnts = atomic_read_acquire(&lock->cnts); } } /** * queued_read_lock_slowpath - acquire read lock of a queue rwlock * @lock: Pointer to queue rwlock structure * @cnts: Current qrwlock lock value */ void queued_read_lock_slowpath(struct qrwlock *lock, u32 cnts) { /* * Readers come here when they cannot get the lock without waiting */ if (unlikely(in_interrupt())) { /* * Readers in interrupt context will get the lock immediately * if the writer is just waiting (not holding the lock yet). * The rspin_until_writer_unlock() function returns immediately * in this case. Otherwise, they will spin (with ACQUIRE * semantics) until the lock is available without waiting in * the queue. */ rspin_until_writer_unlock(lock, cnts); return; } atomic_sub(_QR_BIAS, &lock->cnts); /* * Put the reader into the wait queue */ arch_spin_lock(&lock->wait_lock); /* * The ACQUIRE semantics of the following spinning code ensure * that accesses can't leak upwards out of our subsequent critical * section in the case that the lock is currently held for write. */ cnts = atomic_fetch_add_acquire(_QR_BIAS, &lock->cnts); rspin_until_writer_unlock(lock, cnts); /* * Signal the next one in queue to become queue head */ arch_spin_unlock(&lock->wait_lock); } EXPORT_SYMBOL(queued_read_lock_slowpath); /** * queued_write_lock_slowpath - acquire write lock of a queue rwlock * @lock : Pointer to queue rwlock structure */ void queued_write_lock_slowpath(struct qrwlock *lock) { u32 cnts; /* Put the writer into the wait queue */ arch_spin_lock(&lock->wait_lock); /* Try to acquire the lock directly if no reader is present */ if (!atomic_read(&lock->cnts) && (atomic_cmpxchg_acquire(&lock->cnts, 0, _QW_LOCKED) == 0)) goto unlock; /* * Set the waiting flag to notify readers that a writer is pending, * or wait for a previous writer to go away. */ for (;;) { struct __qrwlock *l = (struct __qrwlock *)lock; if (!READ_ONCE(l->wmode) && (cmpxchg_relaxed(&l->wmode, 0, _QW_WAITING) == 0)) break; cpu_relax(); } /* When no more readers, set the locked flag */ for (;;) { cnts = atomic_read(&lock->cnts); if ((cnts == _QW_WAITING) && (atomic_cmpxchg_acquire(&lock->cnts, _QW_WAITING, _QW_LOCKED) == _QW_WAITING)) break; cpu_relax(); } unlock: arch_spin_unlock(&lock->wait_lock); } EXPORT_SYMBOL(queued_write_lock_slowpath); submit();'>
Diffstat (limited to 'net/mac80211/cfg.c')
td class='right'>2017-01-17 16:13:52 +0200
committerThomas Gleixner <tglx@linutronix.de>2017-01-18 15:37:28 +0100
commit020eb3daaba2857b32c4cf4c82f503d6a00a67de (patch)
tree329a05b424d783db675a4c711bd7633575e8181b /include/net/ip_fib.h
parent49def1853334396f948dcb4cedb9347abb318df5 (diff)
x86/ioapic: Restore IO-APIC irq_chip retrigger callback
commit d32932d02e18 removed the irq_retrigger callback from the IO-APIC chip and did not add it to the new IO-APIC-IR irq chip. Unfortunately the software resend fallback is not enabled on X86, so edge interrupts which are received during the lazy disabled state of the interrupt line are not retriggered and therefor lost. Restore the callbacks. [ tglx: Massaged changelog ] Fixes: d32932d02e18 ("x86/irq: Convert IOAPIC to use hierarchical irqdomain interfaces") Signed-off-by: Ruslan Ruslichenko <rruslich@cisco.com> Cc: xe-linux-external@cisco.com Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1484662432-13580-1-git-send-email-rruslich@cisco.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/net/ip_fib.h')