Pass a cpumask to irq_create_affinity_masks as an additional constraint
to consider when creating the affinity masks. This allows the caller to
exclude specific CPUs, e.g., isolated CPUs (see the 'isolcpus' kernel
command-line parameter).

Signed-off-by: Daniel Wagner <w...@kernel.org>
---
 include/linux/interrupt.h | 16 ++++++++++------
 kernel/irq/affinity.c     | 12 ++++++++++--
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 
51b6484c049345c75816c4a63b4efa813f42f27b..b1a230953514da57e30e601727cd0e94796153d3
 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -284,18 +284,22 @@ struct irq_affinity_notify {
  * @nr_sets:           The number of interrupt sets for which affinity
  *                     spreading is required
  * @set_size:          Array holding the size of each interrupt set
+ * @mask:              cpumask that constrains which CPUs to consider when
+ *                     calculating the number and size of the interrupt sets
  * @calc_sets:         Callback for calculating the number and size
  *                     of interrupt sets
  * @priv:              Private data for usage by @calc_sets, usually a
  *                     pointer to driver/device specific data.
  */
 struct irq_affinity {
-       unsigned int    pre_vectors;
-       unsigned int    post_vectors;
-       unsigned int    nr_sets;
-       unsigned int    set_size[IRQ_AFFINITY_MAX_SETS];
-       void            (*calc_sets)(struct irq_affinity *, unsigned int nvecs);
-       void            *priv;
+       unsigned int            pre_vectors;
+       unsigned int            post_vectors;
+       unsigned int            nr_sets;
+       unsigned int            set_size[IRQ_AFFINITY_MAX_SETS];
+       const struct cpumask    *mask;
+       void                    (*calc_sets)(struct irq_affinity *,
+                                            unsigned int nvecs);
+       void                    *priv;
 };
 
 /**
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 
4013e6ad2b2f1cb91de12bb428b3281105f7d23b..c68156f7847a7920103e39124676d06191304ef6
 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -70,7 +70,13 @@ irq_create_affinity_masks(unsigned int nvecs, struct 
irq_affinity *affd)
         */
        for (i = 0, usedvecs = 0; i < affd->nr_sets; i++) {
                unsigned int nr_masks, this_vecs = affd->set_size[i];
-               struct cpumask *result = group_cpus_evenly(this_vecs, 
&nr_masks);
+               struct cpumask *result;
+
+               if (affd->mask)
+                       result = group_mask_cpus_evenly(this_vecs, affd->mask,
+                                                       &nr_masks);
+               else
+                       result = group_cpus_evenly(this_vecs, &nr_masks);
 
                if (!result) {
                        kfree(masks);
@@ -115,7 +121,9 @@ unsigned int irq_calc_affinity_vectors(unsigned int minvec, 
unsigned int maxvec,
        if (resv > minvec)
                return 0;
 
-       if (affd->calc_sets) {
+       if (affd->mask) {
+               set_vecs = cpumask_weight(affd->mask);
+       } else if (affd->calc_sets) {
                set_vecs = maxvec - resv;
        } else {
                cpus_read_lock();

-- 
2.50.0


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