Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index f4f29b9..4d89ad4 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -7,9 +7,10 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/cpu.h>
+#include <linux/sort.h>
 
 static void irq_spread_init_one(struct cpumask *irqmsk, struct cpumask *nmsk,
-				int cpus_per_vec)
+				unsigned int cpus_per_vec)
 {
 	const struct cpumask *siblmsk;
 	int cpu, sibl;
@@ -94,17 +95,168 @@
 	return nodes;
 }
 
-static int irq_build_affinity_masks(const struct irq_affinity *affd,
-				    int startvec, int numvecs,
-				    cpumask_var_t *node_to_cpumask,
-				    const struct cpumask *cpu_mask,
-				    struct cpumask *nmsk,
-				    struct cpumask *masks)
+struct node_vectors {
+	unsigned id;
+
+	union {
+		unsigned nvectors;
+		unsigned ncpus;
+	};
+};
+
+static int ncpus_cmp_func(const void *l, const void *r)
 {
-	int n, nodes, cpus_per_vec, extra_vecs, done = 0;
-	int last_affv = affd->pre_vectors + numvecs;
-	int curvec = startvec;
+	const struct node_vectors *ln = l;
+	const struct node_vectors *rn = r;
+
+	return ln->ncpus - rn->ncpus;
+}
+
+/*
+ * Allocate vector number for each node, so that for each node:
+ *
+ * 1) the allocated number is >= 1
+ *
+ * 2) the allocated numbver is <= active CPU number of this node
+ *
+ * The actual allocated total vectors may be less than @numvecs when
+ * active total CPU number is less than @numvecs.
+ *
+ * Active CPUs means the CPUs in '@cpu_mask AND @node_to_cpumask[]'
+ * for each node.
+ */
+static void alloc_nodes_vectors(unsigned int numvecs,
+				cpumask_var_t *node_to_cpumask,
+				const struct cpumask *cpu_mask,
+				const nodemask_t nodemsk,
+				struct cpumask *nmsk,
+				struct node_vectors *node_vectors)
+{
+	unsigned n, remaining_ncpus = 0;
+
+	for (n = 0; n < nr_node_ids; n++) {
+		node_vectors[n].id = n;
+		node_vectors[n].ncpus = UINT_MAX;
+	}
+
+	for_each_node_mask(n, nodemsk) {
+		unsigned ncpus;
+
+		cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
+		ncpus = cpumask_weight(nmsk);
+
+		if (!ncpus)
+			continue;
+		remaining_ncpus += ncpus;
+		node_vectors[n].ncpus = ncpus;
+	}
+
+	numvecs = min_t(unsigned, remaining_ncpus, numvecs);
+
+	sort(node_vectors, nr_node_ids, sizeof(node_vectors[0]),
+	     ncpus_cmp_func, NULL);
+
+	/*
+	 * Allocate vectors for each node according to the ratio of this
+	 * node's nr_cpus to remaining un-assigned ncpus. 'numvecs' is
+	 * bigger than number of active numa nodes. Always start the
+	 * allocation from the node with minimized nr_cpus.
+	 *
+	 * This way guarantees that each active node gets allocated at
+	 * least one vector, and the theory is simple: over-allocation
+	 * is only done when this node is assigned by one vector, so
+	 * other nodes will be allocated >= 1 vector, since 'numvecs' is
+	 * bigger than number of numa nodes.
+	 *
+	 * One perfect invariant is that number of allocated vectors for
+	 * each node is <= CPU count of this node:
+	 *
+	 * 1) suppose there are two nodes: A and B
+	 * 	ncpu(X) is CPU count of node X
+	 * 	vecs(X) is the vector count allocated to node X via this
+	 * 	algorithm
+	 *
+	 * 	ncpu(A) <= ncpu(B)
+	 * 	ncpu(A) + ncpu(B) = N
+	 * 	vecs(A) + vecs(B) = V
+	 *
+	 * 	vecs(A) = max(1, round_down(V * ncpu(A) / N))
+	 * 	vecs(B) = V - vecs(A)
+	 *
+	 * 	both N and V are integer, and 2 <= V <= N, suppose
+	 * 	V = N - delta, and 0 <= delta <= N - 2
+	 *
+	 * 2) obviously vecs(A) <= ncpu(A) because:
+	 *
+	 * 	if vecs(A) is 1, then vecs(A) <= ncpu(A) given
+	 * 	ncpu(A) >= 1
+	 *
+	 * 	otherwise,
+	 * 		vecs(A) <= V * ncpu(A) / N <= ncpu(A), given V <= N
+	 *
+	 * 3) prove how vecs(B) <= ncpu(B):
+	 *
+	 * 	if round_down(V * ncpu(A) / N) == 0, vecs(B) won't be
+	 * 	over-allocated, so vecs(B) <= ncpu(B),
+	 *
+	 * 	otherwise:
+	 *
+	 * 	vecs(A) =
+	 * 		round_down(V * ncpu(A) / N) =
+	 * 		round_down((N - delta) * ncpu(A) / N) =
+	 * 		round_down((N * ncpu(A) - delta * ncpu(A)) / N)	 >=
+	 * 		round_down((N * ncpu(A) - delta * N) / N)	 =
+	 * 		cpu(A) - delta
+	 *
+	 * 	then:
+	 *
+	 * 	vecs(A) - V >= ncpu(A) - delta - V
+	 * 	=>
+	 * 	V - vecs(A) <= V + delta - ncpu(A)
+	 * 	=>
+	 * 	vecs(B) <= N - ncpu(A)
+	 * 	=>
+	 * 	vecs(B) <= cpu(B)
+	 *
+	 * For nodes >= 3, it can be thought as one node and another big
+	 * node given that is exactly what this algorithm is implemented,
+	 * and we always re-calculate 'remaining_ncpus' & 'numvecs', and
+	 * finally for each node X: vecs(X) <= ncpu(X).
+	 *
+	 */
+	for (n = 0; n < nr_node_ids; n++) {
+		unsigned nvectors, ncpus;
+
+		if (node_vectors[n].ncpus == UINT_MAX)
+			continue;
+
+		WARN_ON_ONCE(numvecs == 0);
+
+		ncpus = node_vectors[n].ncpus;
+		nvectors = max_t(unsigned, 1,
+				 numvecs * ncpus / remaining_ncpus);
+		WARN_ON_ONCE(nvectors > ncpus);
+
+		node_vectors[n].nvectors = nvectors;
+
+		remaining_ncpus -= ncpus;
+		numvecs -= nvectors;
+	}
+}
+
+static int __irq_build_affinity_masks(unsigned int startvec,
+				      unsigned int numvecs,
+				      unsigned int firstvec,
+				      cpumask_var_t *node_to_cpumask,
+				      const struct cpumask *cpu_mask,
+				      struct cpumask *nmsk,
+				      struct irq_affinity_desc *masks)
+{
+	unsigned int i, n, nodes, cpus_per_vec, extra_vecs, done = 0;
+	unsigned int last_affv = firstvec + numvecs;
+	unsigned int curvec = startvec;
 	nodemask_t nodemsk = NODE_MASK_NONE;
+	struct node_vectors *node_vectors;
 
 	if (!cpumask_weight(cpu_mask))
 		return 0;
@@ -117,103 +269,102 @@
 	 */
 	if (numvecs <= nodes) {
 		for_each_node_mask(n, nodemsk) {
-			cpumask_copy(masks + curvec, node_to_cpumask[n]);
-			if (++done == numvecs)
-				break;
+			cpumask_or(&masks[curvec].mask, &masks[curvec].mask,
+				   node_to_cpumask[n]);
 			if (++curvec == last_affv)
-				curvec = affd->pre_vectors;
+				curvec = firstvec;
 		}
-		goto out;
+		return numvecs;
 	}
 
-	for_each_node_mask(n, nodemsk) {
-		int ncpus, v, vecs_to_assign, vecs_per_node;
+	node_vectors = kcalloc(nr_node_ids,
+			       sizeof(struct node_vectors),
+			       GFP_KERNEL);
+	if (!node_vectors)
+		return -ENOMEM;
 
-		/* Spread the vectors per node */
-		vecs_per_node = (numvecs - (curvec - affd->pre_vectors)) / nodes;
+	/* allocate vector number for each node */
+	alloc_nodes_vectors(numvecs, node_to_cpumask, cpu_mask,
+			    nodemsk, nmsk, node_vectors);
+
+	for (i = 0; i < nr_node_ids; i++) {
+		unsigned int ncpus, v;
+		struct node_vectors *nv = &node_vectors[i];
+
+		if (nv->nvectors == UINT_MAX)
+			continue;
 
 		/* Get the cpus on this node which are in the mask */
-		cpumask_and(nmsk, cpu_mask, node_to_cpumask[n]);
-
-		/* Calculate the number of cpus per vector */
+		cpumask_and(nmsk, cpu_mask, node_to_cpumask[nv->id]);
 		ncpus = cpumask_weight(nmsk);
-		vecs_to_assign = min(vecs_per_node, ncpus);
+		if (!ncpus)
+			continue;
+
+		WARN_ON_ONCE(nv->nvectors > ncpus);
 
 		/* Account for rounding errors */
-		extra_vecs = ncpus - vecs_to_assign * (ncpus / vecs_to_assign);
+		extra_vecs = ncpus - nv->nvectors * (ncpus / nv->nvectors);
 
-		for (v = 0; curvec < last_affv && v < vecs_to_assign;
-		     curvec++, v++) {
-			cpus_per_vec = ncpus / vecs_to_assign;
+		/* Spread allocated vectors on CPUs of the current node */
+		for (v = 0; v < nv->nvectors; v++, curvec++) {
+			cpus_per_vec = ncpus / nv->nvectors;
 
 			/* Account for extra vectors to compensate rounding errors */
 			if (extra_vecs) {
 				cpus_per_vec++;
 				--extra_vecs;
 			}
-			irq_spread_init_one(masks + curvec, nmsk, cpus_per_vec);
+
+			/*
+			 * wrapping has to be considered given 'startvec'
+			 * may start anywhere
+			 */
+			if (curvec >= last_affv)
+				curvec = firstvec;
+			irq_spread_init_one(&masks[curvec].mask, nmsk,
+						cpus_per_vec);
 		}
-
-		done += v;
-		if (done >= numvecs)
-			break;
-		if (curvec >= last_affv)
-			curvec = affd->pre_vectors;
-		--nodes;
+		done += nv->nvectors;
 	}
-
-out:
+	kfree(node_vectors);
 	return done;
 }
 
-/**
- * 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.
+/*
+ * build affinity in two stages:
+ *	1) spread present CPU on these vectors
+ *	2) spread other possible CPUs on these vectors
  */
-struct cpumask *
-irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd)
+static int irq_build_affinity_masks(unsigned int startvec, unsigned int numvecs,
+				    unsigned int firstvec,
+				    struct irq_affinity_desc *masks)
 {
-	int affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
-	int curvec, usedvecs;
-	cpumask_var_t nmsk, npresmsk, *node_to_cpumask;
-	struct cpumask *masks = NULL;
-
-	/*
-	 * If there aren't any vectors left after applying the pre/post
-	 * vectors don't bother with assigning affinity.
-	 */
-	if (nvecs == affd->pre_vectors + affd->post_vectors)
-		return NULL;
+	unsigned int curvec = startvec, nr_present = 0, nr_others = 0;
+	cpumask_var_t *node_to_cpumask;
+	cpumask_var_t nmsk, npresmsk;
+	int ret = -ENOMEM;
 
 	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
-		return NULL;
+		return ret;
 
 	if (!zalloc_cpumask_var(&npresmsk, GFP_KERNEL))
-		goto outcpumsk;
+		goto fail_nmsk;
 
 	node_to_cpumask = alloc_node_to_cpumask();
 	if (!node_to_cpumask)
-		goto outnpresmsk;
-
-	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
-	if (!masks)
-		goto outnodemsk;
-
-	/* 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);
+		goto fail_npresmsk;
 
 	/* Stabilize the cpumasks */
 	get_online_cpus();
 	build_node_to_cpumask(node_to_cpumask);
 
 	/* Spread on present CPUs starting from affd->pre_vectors */
-	usedvecs = irq_build_affinity_masks(affd, curvec, affvecs,
-					    node_to_cpumask, cpu_present_mask,
-					    nmsk, masks);
+	ret = __irq_build_affinity_masks(curvec, numvecs, firstvec,
+					 node_to_cpumask, cpu_present_mask,
+					 nmsk, masks);
+	if (ret < 0)
+		goto fail_build_affinity;
+	nr_present = ret;
 
 	/*
 	 * Spread on non present CPUs starting from the next vector to be
@@ -221,30 +372,118 @@
 	 * vector space, assign the non present CPUs to the already spread
 	 * out vectors.
 	 */
-	if (usedvecs >= affvecs)
-		curvec = affd->pre_vectors;
+	if (nr_present >= numvecs)
+		curvec = firstvec;
 	else
-		curvec = affd->pre_vectors + usedvecs;
+		curvec = firstvec + nr_present;
 	cpumask_andnot(npresmsk, cpu_possible_mask, cpu_present_mask);
-	usedvecs += irq_build_affinity_masks(affd, curvec, affvecs,
-					     node_to_cpumask, npresmsk,
-					     nmsk, masks);
+	ret = __irq_build_affinity_masks(curvec, numvecs, firstvec,
+					 node_to_cpumask, npresmsk, nmsk,
+					 masks);
+	if (ret >= 0)
+		nr_others = ret;
+
+ fail_build_affinity:
 	put_online_cpus();
 
+	if (ret >= 0)
+		WARN_ON(nr_present + nr_others < numvecs);
+
+	free_node_to_cpumask(node_to_cpumask);
+
+ fail_npresmsk:
+	free_cpumask_var(npresmsk);
+
+ fail_nmsk:
+	free_cpumask_var(nmsk);
+	return ret < 0 ? ret : 0;
+}
+
+static void default_calc_sets(struct irq_affinity *affd, unsigned int affvecs)
+{
+	affd->nr_sets = 1;
+	affd->set_size[0] = affvecs;
+}
+
+/**
+ * irq_create_affinity_masks - Create affinity masks for multiqueue spreading
+ * @nvecs:	The total number of vectors
+ * @affd:	Description of the affinity requirements
+ *
+ * Returns the irq_affinity_desc pointer or NULL if allocation failed.
+ */
+struct irq_affinity_desc *
+irq_create_affinity_masks(unsigned int nvecs, struct irq_affinity *affd)
+{
+	unsigned int affvecs, curvec, usedvecs, i;
+	struct irq_affinity_desc *masks = NULL;
+
+	/*
+	 * Determine the number of vectors which need interrupt affinities
+	 * assigned. If the pre/post request exhausts the available vectors
+	 * then nothing to do here except for invoking the calc_sets()
+	 * callback so the device driver can adjust to the situation.
+	 */
+	if (nvecs > affd->pre_vectors + affd->post_vectors)
+		affvecs = nvecs - affd->pre_vectors - affd->post_vectors;
+	else
+		affvecs = 0;
+
+	/*
+	 * Simple invocations do not provide a calc_sets() callback. Install
+	 * the generic one.
+	 */
+	if (!affd->calc_sets)
+		affd->calc_sets = default_calc_sets;
+
+	/* Recalculate the sets */
+	affd->calc_sets(affd, affvecs);
+
+	if (WARN_ON_ONCE(affd->nr_sets > IRQ_AFFINITY_MAX_SETS))
+		return NULL;
+
+	/* Nothing to assign? */
+	if (!affvecs)
+		return NULL;
+
+	masks = kcalloc(nvecs, sizeof(*masks), GFP_KERNEL);
+	if (!masks)
+		return NULL;
+
+	/* Fill out vectors at the beginning that don't need affinity */
+	for (curvec = 0; curvec < affd->pre_vectors; curvec++)
+		cpumask_copy(&masks[curvec].mask, irq_default_affinity);
+
+	/*
+	 * Spread on present CPUs starting from affd->pre_vectors. If we
+	 * have multiple sets, build each sets affinity mask separately.
+	 */
+	for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
+		unsigned int this_vecs = affd->set_size[i];
+		int ret;
+
+		ret = irq_build_affinity_masks(curvec, this_vecs,
+					       curvec, masks);
+		if (ret) {
+			kfree(masks);
+			return NULL;
+		}
+		curvec += this_vecs;
+		usedvecs += this_vecs;
+	}
+
 	/* Fill out vectors at the end that don't need affinity */
 	if (usedvecs >= affvecs)
 		curvec = affd->pre_vectors + affvecs;
 	else
 		curvec = affd->pre_vectors + usedvecs;
 	for (; curvec < nvecs; curvec++)
-		cpumask_copy(masks + curvec, irq_default_affinity);
+		cpumask_copy(&masks[curvec].mask, irq_default_affinity);
 
-outnodemsk:
-	free_node_to_cpumask(node_to_cpumask);
-outnpresmsk:
-	free_cpumask_var(npresmsk);
-outcpumsk:
-	free_cpumask_var(nmsk);
+	/* Mark the managed interrupts */
+	for (i = affd->pre_vectors; i < nvecs - affd->post_vectors; i++)
+		masks[i].is_managed = 1;
+
 	return masks;
 }
 
@@ -254,17 +493,22 @@
  * @maxvec:	The maximum number of vectors available
  * @affd:	Description of the affinity requirements
  */
-int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
+unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
+				       const struct irq_affinity *affd)
 {
-	int resv = affd->pre_vectors + affd->post_vectors;
-	int vecs = maxvec - resv;
-	int ret;
+	unsigned int resv = affd->pre_vectors + affd->post_vectors;
+	unsigned int set_vecs;
 
 	if (resv > minvec)
 		return 0;
 
-	get_online_cpus();
-	ret = min_t(int, cpumask_weight(cpu_possible_mask), vecs) + resv;
-	put_online_cpus();
-	return ret;
+	if (affd->calc_sets) {
+		set_vecs = maxvec - resv;
+	} else {
+		get_online_cpus();
+		set_vecs = cpumask_weight(cpu_possible_mask);
+		put_online_cpus();
+	}
+
+	return resv + min(set_vecs, maxvec - resv);
 }