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