[PATCH 3/5] genirq/affinity: introduce irq_build_affinity()

Ming Lei
2019-01-25T09:54:32Z

Drivers may use this API to build customized irq affinity, one example
is NVMe, which needs to build multiple irq sets, on each of which all
CPUs are spread.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
include/linux/interrupt.h | 12 ++++++++++++
kernel/irq/affinity.c | 27 +++++++++++++++++++++++++++
2 files changed, 39 insertions(+)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index f6cea778cf50..b820b07f3b55 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -323,6 +323,10 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
struct irq_affinity_desc *
irq_create_affinity_masks(int nvec, const struct irq_affinity *affd);

+int irq_build_affinity(const struct irq_affinity *affd, int startvec,
+ int numvecs, int firstvec,
+ struct irq_affinity_desc *masks, int nmasks);
+
int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd);

#else /* CONFIG_SMP */
@@ -368,6 +372,14 @@ irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *aff
return maxvec;
}

+static inline int
+irq_build_affinity(const struct irq_affinity *affd, int startvec,
+ int numvecs, int firstvec,
+ struct irq_affinity_desc *masks, int nmasks)
+{
+ return 0;
+}
+
#endif /* CONFIG_SMP */

/*
diff --git a/kernel/irq/affinity.c b/kernel/irq/affinity.c
index 7b77cbdf739c..524fdcda9f85 100644
--- a/kernel/irq/affinity.c
+++ b/kernel/irq/affinity.c
@@ -232,6 +232,33 @@ static int irq_build_affinity_masks(const struct irq_affinity *affd,
}

/**
+ * irq_build_affinity - build affinity masks for multiqueue spreading
+ * @affd: Description of the affinity requirements
+ * @startvec: The start vector for building affinity masks
+ * @numvec: The number of vectors is needed for building affinity
+ * @firstvec: It is the IRQ vector which we jump to for continue spread
+ * after the last vector(@startvec + @numvec - 1) is built.
+ * @masks: The mask array for storing the affinity masks
+ * @nmasks: The total number of @masks
+ *
+ * Both @startvec and @firstvec are relative to the 1st irq vectorc
+ * allocated to the device.
+ *
+ * Returns 0 if affinty masks is built successfully.
+ */
+int irq_build_affinity(const struct irq_affinity *affd, int startvec,
+ int numvecs, int firstvec,
+ struct irq_affinity_desc *masks, int nmasks)
+{
+ if (startvec >= nmasks || firstvec >= nmasks || numvecs > nmasks)
+ return -EINVAL;
+
+ return irq_build_affinity_masks(affd, startvec, numvecs, firstvec,
+ masks);
+}
+EXPORT_SYMBOL_GPL(irq_build_affinity);
+
+/**
* irq_create_affinity_masks - Create affinity masks for multiqueue spreading
* @nvecs: The total number of vectors
* @affd: Description of the affinity requirements
--
2.9.5