blk-mq: Allow PCI vector offset for mapping queues

The PCI interrupt vectors intended to be associated with a queue may
not start at 0; a driver may allocate pre_vectors for special use. This
patch adds an offset parameter so blk-mq may find the intended affinity
mask and updates all drivers using this API accordingly.

Cc: Don Brace <don.brace@microsemi.com>
Cc: <qla2xxx-upstream@qlogic.com>
Cc: <linux-scsi@vger.kernel.org>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 4 insertions, 2 deletions

diff --git a/block/blk-mq-pci.c b/block/blk-mq-pci.c
index 76944e3271bf..e233996bb76f 100644
--- a/block/blk-mq-pci.c
+++ b/block/blk-mq-pci.c
@@ -21,6 +21,7 @@
  * blk_mq_pci_map_queues - provide a default queue mapping for PCI device
  * @set:        tagset to provide the mapping for
  * @pdev:       PCI device associated with @set.
+ * @offset:     Offset to use for the pci irq vector
  *
  * This function assumes the PCI device @pdev has at least as many available
  * interrupt vectors as @set has queues.  It will then query the vector
@@ -28,13 +29,14 @@
  * that maps a queue to the CPUs that have irq affinity for the corresponding
  * vector.
  */
-int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev)
+int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev,
+                            int offset)
 {
         const struct cpumask *mask;
         unsigned int queue, cpu;
 
         for (queue = 0; queue < set->nr_hw_queues; queue++) {
-                mask = pci_irq_get_affinity(pdev, queue);
+                mask = pci_irq_get_affinity(pdev, queue + offset);
                 if (!mask)
                         goto fallback;