#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; 	/* Calculate the number of nodes in the supplied affinity mask */	for (n = 0, nodes = 0; n < num_online_nodes(); 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 * @affinity:		The affinity mask to spread. If NULL cpu_online_mask *			is used * @nvecs:		The number of vectors * * Returns the masks pointer or NULL if allocation failed. */struct cpumask *irq_create_affinity_masks(const struct cpumask *affinity,					  int nvec){	int n, nodes, vecs_per_node, cpus_per_vec, extra_vecs, curvec = 0;	nodemask_t nodemsk = NODE_MASK_NONE;	struct cpumask *masks;	cpumask_var_t nmsk; 	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))		return NULL; 	masks = kzalloc(nvec * sizeof(*masks), GFP_KERNEL);	if (!masks)		goto out; 	/* Stabilize the cpumasks */	get_online_cpus();	/* If the supplied affinity mask is NULL, use cpu online mask */	if (!affinity)		affinity = cpu_online_mask; 	nodes = get_nodes_in_cpumask(affinity, &nodemsk); 	/*	 * If the number of nodes in the mask is less than or equal the	 * number of vectors we just spread the vectors across the nodes.	 */	if (nvec <= nodes) {		for_each_node_mask(n, nodemsk) {			cpumask_copy(masks + curvec, cpumask_of_node(n));			if (++curvec == nvec)				break;		}		goto outonl;	} 	/* Spread the vectors per node */	vecs_per_node = nvec / nodes;	/* Account for rounding errors */	extra_vecs = nvec - (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, affinity, cpumask_of_node(n)); 		/* Calculate the number of cpus per vector */		ncpus = cpumask_weight(nmsk); 		for (v = 0; curvec < nvec && 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 >= nvec)			break;	} outonl:	put_online_cpus();out:	free_cpumask_var(nmsk);	return masks;} /** * irq_calc_affinity_vectors - Calculate to optimal number of vectors for a given affinity mask * @affinity:		The affinity mask to spread. If NULL cpu_online_mask *			is used * @maxvec:		The maximum number of vectors available */int irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec){	int cpus, ret; 	/* Stabilize the cpumasks */	get_online_cpus();	/* If the supplied affinity mask is NULL, use cpu online mask */	if (!affinity)		affinity = cpu_online_mask; 	cpus = cpumask_weight(affinity);	ret = (cpus < maxvec) ? cpus : maxvec; 	put_online_cpus();	return ret;}