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authorChristoph Hellwig <hch@lst.de>2016-09-14 16:18:56 +0200
committerJens Axboe <axboe@fb.com>2016-09-15 08:42:03 -0600
commit973c4e372c8f71a15ac39765e657ded70fc87d41 (patch)
tree8076126f76d8d0c68cb81f305c4d575fb61ba07a
parentda695ba236b993f07a540d35c17f271ef08c89f3 (diff)
blk-mq: provide a default queue mapping for PCI device
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--block/Makefile2
-rw-r--r--block/blk-mq-pci.c45
-rw-r--r--include/linux/blk-mq-pci.h9
3 files changed, 55 insertions, 1 deletions
diff --git a/block/Makefile b/block/Makefile
index 9eda2322b2d4..2447a0b1ef9c 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -22,4 +22,4 @@ obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
obj-$(CONFIG_BLOCK_COMPAT) += compat_ioctl.o
obj-$(CONFIG_BLK_CMDLINE_PARSER) += cmdline-parser.o
obj-$(CONFIG_BLK_DEV_INTEGRITY) += bio-integrity.o blk-integrity.o t10-pi.o
-
+obj-$(CONFIG_PCI) += blk-mq-pci.o
diff --git a/block/blk-mq-pci.c b/block/blk-mq-pci.c
new file mode 100644
index 000000000000..33c7bd743c63
--- /dev/null
+++ b/block/blk-mq-pci.c
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2016 Christoph Hellwig.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+#include <linux/blk-mq.h>
+#include <linux/blk-mq-pci.h>
+#include <linux/pci.h>
+#include <linux/module.h>
+
+/**
+ * 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.
+ *
+ * This function assumes the PCI device @pdev has at least as many available
+ * interrupt vetors as @set has queues. It will then queuery the vector
+ * corresponding to each queue for it's affinity mask and built queue mapping
+ * 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)
+{
+ const struct cpumask *mask;
+ unsigned int queue, cpu;
+
+ for (queue = 0; queue < set->nr_hw_queues; queue++) {
+ mask = pci_irq_get_affinity(pdev, queue);
+ if (!mask)
+ return -EINVAL;
+
+ for_each_cpu(cpu, mask)
+ set->mq_map[cpu] = queue;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);
diff --git a/include/linux/blk-mq-pci.h b/include/linux/blk-mq-pci.h
new file mode 100644
index 000000000000..6ab595259112
--- /dev/null
+++ b/include/linux/blk-mq-pci.h
@@ -0,0 +1,9 @@
+#ifndef _LINUX_BLK_MQ_PCI_H
+#define _LINUX_BLK_MQ_PCI_H
+
+struct blk_mq_tag_set;
+struct pci_dev;
+
+int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev);
+
+#endif /* _LINUX_BLK_MQ_PCI_H */