lpfc: Fix breakage on big endian kernels
[linux-2.6/btrfs-unstable.git] / lib / cpumask.c
blob830dd5dec40f1697b2bf2e40a294e05284ded89c
1 #include <linux/slab.h>
2 #include <linux/kernel.h>
3 #include <linux/bitops.h>
4 #include <linux/cpumask.h>
5 #include <linux/export.h>
6 #include <linux/bootmem.h>
8 /**
9 * cpumask_next_and - get the next cpu in *src1p & *src2p
10 * @n: the cpu prior to the place to search (ie. return will be > @n)
11 * @src1p: the first cpumask pointer
12 * @src2p: the second cpumask pointer
14 * Returns >= nr_cpu_ids if no further cpus set in both.
16 int cpumask_next_and(int n, const struct cpumask *src1p,
17 const struct cpumask *src2p)
19 struct cpumask tmp;
21 if (cpumask_and(&tmp, src1p, src2p))
22 return cpumask_next(n, &tmp);
23 return nr_cpu_ids;
25 EXPORT_SYMBOL(cpumask_next_and);
27 /**
28 * cpumask_any_but - return a "random" in a cpumask, but not this one.
29 * @mask: the cpumask to search
30 * @cpu: the cpu to ignore.
32 * Often used to find any cpu but smp_processor_id() in a mask.
33 * Returns >= nr_cpu_ids if no cpus set.
35 int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
37 unsigned int i;
39 cpumask_check(cpu);
40 for_each_cpu(i, mask)
41 if (i != cpu)
42 break;
43 return i;
46 /* These are not inline because of header tangles. */
47 #ifdef CONFIG_CPUMASK_OFFSTACK
48 /**
49 * alloc_cpumask_var_node - allocate a struct cpumask on a given node
50 * @mask: pointer to cpumask_var_t where the cpumask is returned
51 * @flags: GFP_ flags
53 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
54 * a nop returning a constant 1 (in <linux/cpumask.h>)
55 * Returns TRUE if memory allocation succeeded, FALSE otherwise.
57 * In addition, mask will be NULL if this fails. Note that gcc is
58 * usually smart enough to know that mask can never be NULL if
59 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
60 * too.
62 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
64 *mask = kmalloc_node(cpumask_size(), flags, node);
66 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
67 if (!*mask) {
68 printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
69 dump_stack();
71 #endif
73 return *mask != NULL;
75 EXPORT_SYMBOL(alloc_cpumask_var_node);
77 bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
79 return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
81 EXPORT_SYMBOL(zalloc_cpumask_var_node);
83 /**
84 * alloc_cpumask_var - allocate a struct cpumask
85 * @mask: pointer to cpumask_var_t where the cpumask is returned
86 * @flags: GFP_ flags
88 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
89 * a nop returning a constant 1 (in <linux/cpumask.h>).
91 * See alloc_cpumask_var_node.
93 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
95 return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
97 EXPORT_SYMBOL(alloc_cpumask_var);
99 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
101 return alloc_cpumask_var(mask, flags | __GFP_ZERO);
103 EXPORT_SYMBOL(zalloc_cpumask_var);
106 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
107 * @mask: pointer to cpumask_var_t where the cpumask is returned
109 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
110 * a nop (in <linux/cpumask.h>).
111 * Either returns an allocated (zero-filled) cpumask, or causes the
112 * system to panic.
114 void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
116 *mask = memblock_virt_alloc(cpumask_size(), 0);
120 * free_cpumask_var - frees memory allocated for a struct cpumask.
121 * @mask: cpumask to free
123 * This is safe on a NULL mask.
125 void free_cpumask_var(cpumask_var_t mask)
127 kfree(mask);
129 EXPORT_SYMBOL(free_cpumask_var);
132 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
133 * @mask: cpumask to free
135 void __init free_bootmem_cpumask_var(cpumask_var_t mask)
137 memblock_free_early(__pa(mask), cpumask_size());
139 #endif
142 * cpumask_set_cpu_local_first - set i'th cpu with local numa cpu's first
144 * @i: index number
145 * @numa_node: local numa_node
146 * @dstp: cpumask with the relevant cpu bit set according to the policy
148 * This function sets the cpumask according to a numa aware policy.
149 * cpumask could be used as an affinity hint for the IRQ related to a
150 * queue. When the policy is to spread queues across cores - local cores
151 * first.
153 * Returns 0 on success, -ENOMEM for no memory, and -EAGAIN when failed to set
154 * the cpu bit and need to re-call the function.
156 int cpumask_set_cpu_local_first(int i, int numa_node, cpumask_t *dstp)
158 cpumask_var_t mask;
159 int cpu;
160 int ret = 0;
162 if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
163 return -ENOMEM;
165 i %= num_online_cpus();
167 if (numa_node == -1 || !cpumask_of_node(numa_node)) {
168 /* Use all online cpu's for non numa aware system */
169 cpumask_copy(mask, cpu_online_mask);
170 } else {
171 int n;
173 cpumask_and(mask,
174 cpumask_of_node(numa_node), cpu_online_mask);
176 n = cpumask_weight(mask);
177 if (i >= n) {
178 i -= n;
180 /* If index > number of local cpu's, mask out local
181 * cpu's
183 cpumask_andnot(mask, cpu_online_mask, mask);
187 for_each_cpu(cpu, mask) {
188 if (--i < 0)
189 goto out;
192 ret = -EAGAIN;
194 out:
195 free_cpumask_var(mask);
197 if (!ret)
198 cpumask_set_cpu(cpu, dstp);
200 return ret;
202 EXPORT_SYMBOL(cpumask_set_cpu_local_first);