FreeBSD/Linux Kernel Cross Reference
sys/lib/cpumask.c

     #include <linux/slab.h>
     #include <linux/kernel.h>
     #include <linux/bitops.h>
     #include <linux/cpumask.h>
     #include <linux/export.h>
     #include <linux/bootmem.h>
     
     int __first_cpu(const cpumask_t *srcp)
     {
            return min_t(int, NR_CPUS, find_first_bit(srcp->bits, NR_CPUS));
    }
    EXPORT_SYMBOL(__first_cpu);
    
    int __next_cpu(int n, const cpumask_t *srcp)
    {
            return min_t(int, NR_CPUS, find_next_bit(srcp->bits, NR_CPUS, n+1));
    }
    EXPORT_SYMBOL(__next_cpu);
    
    #if NR_CPUS > 64
    int __next_cpu_nr(int n, const cpumask_t *srcp)
    {
            return min_t(int, nr_cpu_ids,
                                    find_next_bit(srcp->bits, nr_cpu_ids, n+1));
    }
    EXPORT_SYMBOL(__next_cpu_nr);
    #endif
    
    /**
     * cpumask_next_and - get the next cpu in *src1p & *src2p
     * @n: the cpu prior to the place to search (ie. return will be > @n)
     * @src1p: the first cpumask pointer
     * @src2p: the second cpumask pointer
     *
     * Returns >= nr_cpu_ids if no further cpus set in both.
     */
    int cpumask_next_and(int n, const struct cpumask *src1p,
                         const struct cpumask *src2p)
    {
            while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
                    if (cpumask_test_cpu(n, src2p))
                            break;
            return n;
    }
    EXPORT_SYMBOL(cpumask_next_and);
    
    /**
     * cpumask_any_but - return a "random" in a cpumask, but not this one.
     * @mask: the cpumask to search
     * @cpu: the cpu to ignore.
     *
     * Often used to find any cpu but smp_processor_id() in a mask.
     * Returns >= nr_cpu_ids if no cpus set.
     */
    int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
    {
            unsigned int i;
    
            cpumask_check(cpu);
            for_each_cpu(i, mask)
                    if (i != cpu)
                            break;
            return i;
    }
    
    /* These are not inline because of header tangles. */
    #ifdef CONFIG_CPUMASK_OFFSTACK
    /**
     * alloc_cpumask_var_node - allocate a struct cpumask on a given node
     * @mask: pointer to cpumask_var_t where the cpumask is returned
     * @flags: GFP_ flags
     *
     * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
     * a nop returning a constant 1 (in <linux/cpumask.h>)
     * Returns TRUE if memory allocation succeeded, FALSE otherwise.
     *
     * In addition, mask will be NULL if this fails.  Note that gcc is
     * usually smart enough to know that mask can never be NULL if
     * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
     * too.
     */
    bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
    {
            *mask = kmalloc_node(cpumask_size(), flags, node);
    
    #ifdef CONFIG_DEBUG_PER_CPU_MAPS
            if (!*mask) {
                    printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
                    dump_stack();
            }
    #endif
            /* FIXME: Bandaid to save us from old primitives which go to NR_CPUS. */
            if (*mask) {
                    unsigned char *ptr = (unsigned char *)cpumask_bits(*mask);
                    unsigned int tail;
                    tail = BITS_TO_LONGS(NR_CPUS - nr_cpumask_bits) * sizeof(long);
                    memset(ptr + cpumask_size() - tail, 0, tail);
            }
    
           return *mask != NULL;
   }
   EXPORT_SYMBOL(alloc_cpumask_var_node);
   
   bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
   {
           return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
   }
   EXPORT_SYMBOL(zalloc_cpumask_var_node);
   
   /**
    * alloc_cpumask_var - allocate a struct cpumask
    * @mask: pointer to cpumask_var_t where the cpumask is returned
    * @flags: GFP_ flags
    *
    * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
    * a nop returning a constant 1 (in <linux/cpumask.h>).
    *
    * See alloc_cpumask_var_node.
    */
   bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
   {
           return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
   }
   EXPORT_SYMBOL(alloc_cpumask_var);
   
   bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
   {
           return alloc_cpumask_var(mask, flags | __GFP_ZERO);
   }
   EXPORT_SYMBOL(zalloc_cpumask_var);
   
   /**
    * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
    * @mask: pointer to cpumask_var_t where the cpumask is returned
    *
    * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
    * a nop (in <linux/cpumask.h>).
    * Either returns an allocated (zero-filled) cpumask, or causes the
    * system to panic.
    */
   void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
   {
           *mask = alloc_bootmem(cpumask_size());
   }
   
   /**
    * free_cpumask_var - frees memory allocated for a struct cpumask.
    * @mask: cpumask to free
    *
    * This is safe on a NULL mask.
    */
   void free_cpumask_var(cpumask_var_t mask)
   {
           kfree(mask);
   }
   EXPORT_SYMBOL(free_cpumask_var);
   
   /**
    * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
    * @mask: cpumask to free
    */
   void __init free_bootmem_cpumask_var(cpumask_var_t mask)
   {
           free_bootmem(__pa(mask), cpumask_size());
   }
   #endif

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