#include <linux/interrupt.h>#include <linux/kernel.h>#include <linux/slab.h>#include <linux/cpu.h> static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,				int cpus_per_vec){	const struct cpumask *siblmsk;	int cpu, sibl; 	for ( ; cpus_per_vec > 0; ) {		cpu = cpumask_first(nmsk); 		/* Should not happen, but I'm too lazy to think about it */		if (cpu >= nr_cpu_ids)			return; 		cpumask_clear_cpu(cpu, nmsk);		cpumask_set_cpu(cpu, irqmsk);		cpus_per_vec--; 		/* If the cpu has siblings, use them first */		siblmsk = topology_sibling_cpumask(cpu);		for (sibl = -1; cpus_per_vec > 0; ) {			sibl = cpumask_next(sibl, siblmsk);			if (sibl >= nr_cpu_ids)				break;			if (!cpumask_test_and_clear_cpu(sibl, nmsk))				continue;			cpumask_set_cpu(sibl, irqmsk);			cpus_per_vec--;		}	}} static int get_nodes_in_cpumask(const struct cpumask *mask, nodemask_t *nodemsk){	int n, nodes = 0; 	/* Calculate the number of nodes in the supplied affinity mask */	for_each_online_node(n) {		if (cpumask_intersects(mask, cpumask_of_node(n))) {			node_set(n, *nodemsk);			nodes++;		}	}	return nodes;} /** * irq_create_affinity_masks - Create affinity masks for multiqueue spreading * @nvecs:	The total number of vectors * @affd:	Description of the affinity requirements * * Returns the masks pointer or NULL if allocation failed. */struct cpumask *irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd){	int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec;	int affv = nvecs - affd->pre_vectors - affd->post_vectors;	int last_affv = affv + affd->pre_vectors;	nodemask_t nodemsk = NODE_MASK_NONE;	struct cpumask *masks;	cpumask_var_t nmsk; 	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))		return NULL; 	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);	if (!masks)		goto out; 	/* Fill out vectors at the beginning that don't need affinity */	for (curvec = 0; curvec < affd->pre_vectors; curvec++)		cpumask_copy(masks + curvec, irq_default_affinity); 	/* Stabilize the cpumasks */	get_online_cpus();	nodes = get_nodes_in_cpumask(cpu_online_mask, &nodemsk); 	/*	 * If the number of nodes in the mask is greater than or equal the	 * number of vectors we just spread the vectors across the nodes.	 */	if (affv <= nodes) {		for_each_node_mask(n, nodemsk) {			cpumask_copy(masks + curvec, cpumask_of_node(n));			if (++curvec == last_affv)				break;		}		goto done;	} 	/* Spread the vectors per node */	vecs_per_node = affv / nodes;	/* Account for rounding errors */	extra_vecs = affv - (nodes * vecs_per_node); 	for_each_node_mask(n, nodemsk) {		int ncpus, v, vecs_to_assign = vecs_per_node; 		/* Get the cpus on this node which are in the mask */		cpumask_and(nmsk, cpu_online_mask, cpumask_of_node(n)); 		/* Calculate the number of cpus per vector */		ncpus = cpumask_weight(nmsk); 		for (v = 0; curvec < last_affv && v < vecs_to_assign;		     curvec++, v++) {			cpus_per_vec = ncpus / vecs_to_assign; 			/* Account for extra vectors to compensate rounding errors */			if (extra_vecs) {				cpus_per_vec++;				if (!--extra_vecs)					vecs_per_node++;			}			irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);		} 		if (curvec >= last_affv)			break;	} done:	put_online_cpus(); 	/* Fill out vectors at the end that don't need affinity */	for (; curvec < nvecs; curvec++)		cpumask_copy(masks + curvec, irq_default_affinity);out:	free_cpumask_var(nmsk);	return masks;} /** * irq_calc_affinity_vectors - Calculate the optimal number of vectors * @maxvec:	The maximum number of vectors available * @affd:	Description of the affinity requirements */int irq_calc_affinity_vectors(int maxvec, const struct irq_affinity *affd){	int resv = affd->pre_vectors + affd->post_vectors;	int vecs = maxvec - resv;	int cpus; 	/* Stabilize the cpumasks */	get_online_cpus();	cpus = cpumask_weight(cpu_online_mask);	put_online_cpus(); 	return min(cpus, vecs) + resv;}