Re: [PATCH 11/14] irq: add support for allocating (and affinitizing) sets of IRQs
From: Keith Busch <hidden>
Date: 2018-10-30 14:28:26
Also in:
linux-scsi, lkml
On Mon, Oct 29, 2018 at 10:37:35AM -0600, Jens Axboe wrote:
quoted hunk ↗ jump to hunk
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c index f4f29b9d90ee..2046a0f0f0f1 100644 --- a/kernel/irq/affinity.c +++ b/kernel/irq/affinity.c@@ -180,6 +180,7 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) int curvec, usedvecs; cpumask_var_t nmsk, npresmsk, *node_to_cpumask; struct cpumask *masks = NULL; + int i, nr_sets; /* * If there aren't any vectors left after applying the pre/post@@ -210,10 +211,23 @@ irq_create_affinity_masks(int nvecs, const struct irq_affinity *affd) 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); + /* + * Spread on present CPUs starting from affd->pre_vectors. If we + * have multiple sets, build each sets affinity mask separately. + */ + nr_sets = affd->nr_sets; + if (!nr_sets) + nr_sets = 1; + + for (i = 0, usedvecs = 0; i < nr_sets; i++) { + int this_vecs = affd->sets ? affd->sets[i] : affvecs; + int nr; + + nr = irq_build_affinity_masks(affd, curvec, this_vecs, + node_to_cpumask, cpu_present_mask, + nmsk, masks + usedvecs); + usedvecs += nr; + }
While the code below returns the appropriate number of possible vectors when a set requested too many, the above code is still using the value from the set, which may exceed 'nvecs' used to kcalloc 'masks', so 'masks + usedvecs' may go out of bounds.
quoted hunk ↗ jump to hunk
/* * Spread on non present CPUs starting from the next vector to be@@ -258,13 +272,21 @@ int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity { int resv = affd->pre_vectors + affd->post_vectors; int vecs = maxvec - resv; - int ret; + 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->nr_sets) { + int i; + + for (i = 0, set_vecs = 0; i < affd->nr_sets; i++) + set_vecs += affd->sets[i]; + } else { + get_online_cpus(); + set_vecs = cpumask_weight(cpu_possible_mask); + put_online_cpus(); + } + + return resv + min(set_vecs, vecs); }