From: Ming Lei <redacted>

blk_mq_pci_map_queues and blk_mq_virtio_map_queues will create a CPU to
hardware queue mapping based on affinity information. These two
function share code which only differs on how the affinity information
is retrieved. Also there is the hisi_sas which open codes the same loop.

Thus introduce a new helper function for creating these mappings which
takes an callback function for fetching the affinity mask. Also
introduce common helper function for PCI and virtio devices to retrieve
affinity masks.

Signed-off-by: Ming Lei <redacted>
[dwagner: - removed fallback mapping
          - added affintity helpers
	  - updated commit message]
Signed-off-by: Daniel Wagner <redacted>
---
 block/blk-mq-cpumap.c         | 35 +++++++++++++++++++++++++++++++++++
 block/blk-mq-pci.c            | 18 ++++++++++++++++++
 block/blk-mq-virtio.c         | 19 +++++++++++++++++++
 include/linux/blk-mq-pci.h    |  2 ++
 include/linux/blk-mq-virtio.h |  3 +++
 include/linux/blk-mq.h        |  5 +++++
 6 files changed, 82 insertions(+)

diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
index 9638b25fd521..7037a2dc485f 100644
--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c

@@ -54,3 +54,38 @@ int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
 
 	return NUMA_NO_NODE;
 }
+
+/**
+ * blk_mq_dev_map_queues - Create CPU to hardware queue mapping
+ * @qmap:	CPU to hardware queue map.
+ * @dev_off:	Offset to use for the device.
+ * @dev_data:	Device data passed to get_queue_affinity().
+ * @get_queue_affinity:	Callback to retrieve queue affinity.
+ *
+ * Create a CPU to hardware queue mapping in @qmap. For each queue
+ * @get_queue_affinity will be called to retrieve the affinity for given
+ * queue.
+ */
+void blk_mq_dev_map_queues(struct blk_mq_queue_map *qmap,
+			   void *dev_data, int dev_off,
+			   get_queue_affinty_fn *get_queue_affinity)
+{
+	const struct cpumask *mask;
+	unsigned int queue, cpu;
+
+	for (queue = 0; queue < qmap->nr_queues; queue++) {
+		mask = get_queue_affinity(dev_data, dev_off, queue);
+		if (!mask)
+			goto fallback;
+
+		for_each_cpu(cpu, mask)
+			qmap->mq_map[cpu] = qmap->queue_offset + queue;
+	}
+
+	return;
+
+fallback:
+	WARN_ON_ONCE(qmap->nr_queues > 1);
+	blk_mq_clear_mq_map(qmap);
+}
+EXPORT_SYMBOL_GPL(blk_mq_dev_map_queues);

diff --git a/block/blk-mq-pci.c b/block/blk-mq-pci.c
index d47b5c73c9eb..71a73238aeb2 100644
--- a/block/blk-mq-pci.c
+++ b/block/blk-mq-pci.c

@@ -44,3 +44,21 @@ void blk_mq_pci_map_queues(struct blk_mq_queue_map *qmap, struct pci_dev *pdev,
 	blk_mq_clear_mq_map(qmap);
 }
 EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);
+
+/**
+ * blk_mq_pci_get_queue_affinity - get affinity mask queue mapping for PCI device
+ * @dev_data:	Pointer to struct pci_dev.
+ * @offset:	Offset to use for the pci irq vector
+ * @queue:	Queue index
+ *
+ * This function returns for a queue the affinity mask for a PCI device.
+ * It is usually used as callback for blk_mq_dev_map_queues().
+ */
+const struct cpumask *blk_mq_pci_get_queue_affinity(void *dev_data, int offset,
+						    int queue)
+{
+	struct pci_dev *pdev = dev_data;
+
+	return pci_irq_get_affinity(pdev, offset + queue);
+}
+EXPORT_SYMBOL_GPL(blk_mq_pci_get_queue_affinity);

diff --git a/block/blk-mq-virtio.c b/block/blk-mq-virtio.c
index 68d0945c0b08..d3d33f8d69ce 100644
--- a/block/blk-mq-virtio.c
+++ b/block/blk-mq-virtio.c

@@ -44,3 +44,22 @@ void blk_mq_virtio_map_queues(struct blk_mq_queue_map *qmap,
 	blk_mq_map_queues(qmap);
 }
 EXPORT_SYMBOL_GPL(blk_mq_virtio_map_queues);
+
+/**
+ * blk_mq_virtio_get_queue_affinity - get affinity mask queue mapping for virtio device