#ifndef _ASM_GENERIC_BITOPS_ATOMIC_H_ #define _ASM_GENERIC_BITOPS_ATOMIC_H_ #include #include #ifdef CONFIG_SMP #include #include /* we use L1_CACHE_BYTES */ /* Use an array of spinlocks for our atomic_ts. * Hash function to index into a different SPINLOCK. * Since "a" is usually an address, use one spinlock per cacheline. */ # define ATOMIC_HASH_SIZE 4 # define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) a)/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ])) extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned; /* Can't use raw_spin_lock_irq because of #include problems, so * this is the substitute */ #define _atomic_spin_lock_irqsave(l,f) do { \ arch_spinlock_t *s = ATOMIC_HASH(l); \ local_irq_save(f); \ arch_spin_lock(s); \ } while(0) #define _atomic_spin_unlock_irqrestore(l,f) do { \ arch_spinlock_t *s = ATOMIC_HASH(l); \ arch_spin_unlock(s); \ local_irq_restore(f); \ } while(0) #else # define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0) # define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0) #endif /* * NMI events can occur at any time, including when interrupts have been * disabled by *_irqsave(). So you can get NMI events occurring while a * *_bit function is holding a spin lock. If the NMI handler also wants * to do bit manipulation (and they do) then you can get a deadlock * between the original caller of *_bit() and the NMI handler. * * by Keith Owens */ /** * set_bit - Atomically set a bit in memory * @nr: the bit to set * @addr: the address to start counting from * * This function is atomic and may not be reordered. See __set_bit() * if you do not require the atomic guarantees. * * Note: there are no guarantees that this function will not be reordered * on non x86 architectures, so if you are writing portable code, * make sure not to rely on its reordering guarantees. * * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ static inline void set_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long flags; _atomic_spin_lock_irqsave(p, flags); *p |= mask; _atomic_spin_unlock_irqrestore(p, flags); } /** * clear_bit - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from * * clear_bit() is atomic and may not be reordered. However, it does * not contain a memory barrier, so if it is used for locking purposes, * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic() * in order to ensure changes are visible on other processors. */ static inline void clear_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long flags; _atomic_spin_lock_irqsave(p, flags); *p &= ~mask; _atomic_spin_unlock_irqrestore(p, flags); } /** * change_bit - Toggle a bit in memory * @nr: Bit to change * @addr: Address to start counting from * * change_bit() is atomic and may not be reordered. It may be * reordered on other architectures than x86. * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ static inline void change_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long flags; _atomic_spin_lock_irqsave(p, flags); *p ^= mask; _atomic_spin_unlock_irqrestore(p, flags); } /** * test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It may be reordered on other architectures than x86. * It also implies a memory barrier. */ static inline int test_and_set_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long old; unsigned long flags; _atomic_spin_lock_irqsave(p, flags); old = *p; *p = old | mask; _atomic_spin_unlock_irqrestore(p, flags); return (old & mask) != 0; } /** * test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It can be reorderdered on other architectures other than x86. * It also implies a memory barrier. */ static inline int test_and_clear_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long old; unsigned long flags; _atomic_spin_lock_irqsave(p, flags); old = *p; *p = old & ~mask; _atomic_spin_unlock_irqrestore(p, flags); return (old & mask) != 0; } /** * test_and_change_bit - Change a bit and return its old value * @nr: Bit to change * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ static inline int test_and_change_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long old; unsigned long flags; _atomic_spin_lock_irqsave(p, flags); old = *p; *p = old ^ mask; _atomic_spin_unlock_irqrestore(p, flags); return (old & mask) != 0; } #endif /* _ASM_GENERIC_BITOPS_ATOMIC_H */ d>David S. Miller1-2/+4 2017-02-02netfilter: allow logging from non-init namespacesMichal Kubeček2-2/+2 2017-02-02netfilter: add and use nf_ct_set helperFlorian Westphal3-6/+3 2017-02-02skbuff: add and use skb_nfct helperFlorian Westphal4-8/+8 2017-02-02netfilter: reset netfilter state when duplicating packetFlorian Westphal1-1/+1 2017-02-02netfilter: conntrack: no need to pass ctinfo to error handlerFlorian Westphal1-6/+6