[PATCH 11/14] irq: add support for allocating (and affinitizing) sets of IRQs

[Jens Axboe]

A driver may have a need to allocate multiple sets of MSI/MSI-X
interrupts, and have them appropriately affinitized. Add support for
defining a number of sets in the irq_affinity structure, of varying
sizes, and get each set affinitized correctly across the machine.

Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux-ker...@vger.kernel.org
Reviewed-by: Hannes Reinecke <h...@suse.com>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
 include/linux/interrupt.h |  4 ++++
 kernel/irq/affinity.c     | 40 ++++++++++++++++++++++++++++++---------
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 1d6711c28271..ca397ff40836 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -247,10 +247,14 @@ struct irq_affinity_notify {
  *                     the MSI(-X) vector space
  * @post_vectors:      Don't apply affinity to @post_vectors at end of
  *                     the MSI(-X) vector space
+ * @nr_sets:           Length of passed in *sets array
+ * @sets:              Number of affinitized sets
  */
 struct irq_affinity {
        int     pre_vectors;
        int     post_vectors;
+       int     nr_sets;
+       int     *sets;
 };
 
 #if defined(CONFIG_SMP)
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;
+       }
 
        /*
         * 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);
 }
-- 
2.17.1