1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/slab.h> 3 #include <linux/kernel.h> 4 #include <linux/bitops.h> 5 #include <linux/cpumask.h> 6 #include <linux/export.h> 7 #include <linux/memblock.h> 8 9 /** 10 * cpumask_next - get the next cpu in a cpumask 11 * @n: the cpu prior to the place to search (ie. return will be > @n) 12 * @srcp: the cpumask pointer 13 * 14 * Returns >= nr_cpu_ids if no further cpus set. 15 */ 16 unsigned int cpumask_next(int n, const struct cpumask *srcp) 17 { 18 /* -1 is a legal arg here. */ 19 if (n != -1) 20 cpumask_check(n); 21 return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1); 22 } 23 EXPORT_SYMBOL(cpumask_next); 24 25 /** 26 * cpumask_next_and - get the next cpu in *src1p & *src2p 27 * @n: the cpu prior to the place to search (ie. return will be > @n) 28 * @src1p: the first cpumask pointer 29 * @src2p: the second cpumask pointer 30 * 31 * Returns >= nr_cpu_ids if no further cpus set in both. 32 */ 33 int cpumask_next_and(int n, const struct cpumask *src1p, 34 const struct cpumask *src2p) 35 { 36 /* -1 is a legal arg here. */ 37 if (n != -1) 38 cpumask_check(n); 39 return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p), 40 nr_cpumask_bits, n + 1); 41 } 42 EXPORT_SYMBOL(cpumask_next_and); 43 44 /** 45 * cpumask_any_but - return a "random" in a cpumask, but not this one. 46 * @mask: the cpumask to search 47 * @cpu: the cpu to ignore. 48 * 49 * Often used to find any cpu but smp_processor_id() in a mask. 50 * Returns >= nr_cpu_ids if no cpus set. 51 */ 52 int cpumask_any_but(const struct cpumask *mask, unsigned int cpu) 53 { 54 unsigned int i; 55 56 cpumask_check(cpu); 57 for_each_cpu(i, mask) 58 if (i != cpu) 59 break; 60 return i; 61 } 62 EXPORT_SYMBOL(cpumask_any_but); 63 64 /** 65 * cpumask_next_wrap - helper to implement for_each_cpu_wrap 66 * @n: the cpu prior to the place to search 67 * @mask: the cpumask pointer 68 * @start: the start point of the iteration 69 * @wrap: assume @n crossing @start terminates the iteration 70 * 71 * Returns >= nr_cpu_ids on completion 72 * 73 * Note: the @wrap argument is required for the start condition when 74 * we cannot assume @start is set in @mask. 75 */ 76 int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap) 77 { 78 int next; 79 80 again: 81 next = cpumask_next(n, mask); 82 83 if (wrap && n < start && next >= start) { 84 return nr_cpumask_bits; 85 86 } else if (next >= nr_cpumask_bits) { 87 wrap = true; 88 n = -1; 89 goto again; 90 } 91 92 return next; 93 } 94 EXPORT_SYMBOL(cpumask_next_wrap); 95 96 /* These are not inline because of header tangles. */ 97 #ifdef CONFIG_CPUMASK_OFFSTACK 98 /** 99 * alloc_cpumask_var_node - allocate a struct cpumask on a given node 100 * @mask: pointer to cpumask_var_t where the cpumask is returned 101 * @flags: GFP_ flags 102 * 103 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 104 * a nop returning a constant 1 (in <linux/cpumask.h>) 105 * Returns TRUE if memory allocation succeeded, FALSE otherwise. 106 * 107 * In addition, mask will be NULL if this fails. Note that gcc is 108 * usually smart enough to know that mask can never be NULL if 109 * CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case 110 * too. 111 */ 112 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) 113 { 114 *mask = kmalloc_node(cpumask_size(), flags, node); 115 116 #ifdef CONFIG_DEBUG_PER_CPU_MAPS 117 if (!*mask) { 118 printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); 119 dump_stack(); 120 } 121 #endif 122 123 return *mask != NULL; 124 } 125 EXPORT_SYMBOL(alloc_cpumask_var_node); 126 127 bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) 128 { 129 return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node); 130 } 131 EXPORT_SYMBOL(zalloc_cpumask_var_node); 132 133 /** 134 * alloc_cpumask_var - allocate a struct cpumask 135 * @mask: pointer to cpumask_var_t where the cpumask is returned 136 * @flags: GFP_ flags 137 * 138 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 139 * a nop returning a constant 1 (in <linux/cpumask.h>). 140 * 141 * See alloc_cpumask_var_node. 142 */ 143 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) 144 { 145 return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE); 146 } 147 EXPORT_SYMBOL(alloc_cpumask_var); 148 149 bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags) 150 { 151 return alloc_cpumask_var(mask, flags | __GFP_ZERO); 152 } 153 EXPORT_SYMBOL(zalloc_cpumask_var); 154 155 /** 156 * alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena. 157 * @mask: pointer to cpumask_var_t where the cpumask is returned 158 * 159 * Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is 160 * a nop (in <linux/cpumask.h>). 161 * Either returns an allocated (zero-filled) cpumask, or causes the 162 * system to panic. 163 */ 164 void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) 165 { 166 *mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES); 167 } 168 169 /** 170 * free_cpumask_var - frees memory allocated for a struct cpumask. 171 * @mask: cpumask to free 172 * 173 * This is safe on a NULL mask. 174 */ 175 void free_cpumask_var(cpumask_var_t mask) 176 { 177 kfree(mask); 178 } 179 EXPORT_SYMBOL(free_cpumask_var); 180 181 /** 182 * free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var 183 * @mask: cpumask to free 184 */ 185 void __init free_bootmem_cpumask_var(cpumask_var_t mask) 186 { 187 memblock_free_early(__pa(mask), cpumask_size()); 188 } 189 #endif 190 191 /** 192 * cpumask_local_spread - select the i'th cpu with local numa cpu's first 193 * @i: index number 194 * @node: local numa_node 195 * 196 * This function selects an online CPU according to a numa aware policy; 197 * local cpus are returned first, followed by non-local ones, then it 198 * wraps around. 199 * 200 * It's not very efficient, but useful for setup. 201 */ 202 unsigned int cpumask_local_spread(unsigned int i, int node) 203 { 204 int cpu; 205 206 /* Wrap: we always want a cpu. */ 207 i %= num_online_cpus(); 208 209 if (node == -1) { 210 for_each_cpu(cpu, cpu_online_mask) 211 if (i-- == 0) 212 return cpu; 213 } else { 214 /* NUMA first. */ 215 for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask) 216 if (i-- == 0) 217 return cpu; 218 219 for_each_cpu(cpu, cpu_online_mask) { 220 /* Skip NUMA nodes, done above. */ 221 if (cpumask_test_cpu(cpu, cpumask_of_node(node))) 222 continue; 223 224 if (i-- == 0) 225 return cpu; 226 } 227 } 228 BUG(); 229 } 230 EXPORT_SYMBOL(cpumask_local_spread); 231