virtio_scsi: use virtio IRQ affinity

Use automatic IRQ affinity assignment in the virtio layer if available,
and build the blk-mq queues based on it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index c9c5ea0611e9be5113d2030677e0dd24ccd89b0d..939c47df73fa9756faa94fb7eede86a919f1144a 100644 (file)
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/mempool.h>
+#include <linux/interrupt.h>
 #include <linux/virtio.h>
 #include <linux/virtio_ids.h>
 #include <linux/virtio_config.h>
@@ -29,6 +30,7 @@
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_tcq.h>
 #include <linux/seqlock.h>
+#include <linux/blk-mq-virtio.h>
 
 #define VIRTIO_SCSI_MEMPOOL_SZ 64
 #define VIRTIO_SCSI_EVENT_LEN 8
@@ -108,7 +110,6 @@ struct virtio_scsi {
        bool affinity_hint_set;
 
        struct hlist_node node;
-       struct hlist_node node_dead;
 
        /* Protected by event_vq lock */
        bool stop_events;
@@ -118,7 +119,6 @@ struct virtio_scsi {
        struct virtio_scsi_vq req_vqs[];
 };
 
-static enum cpuhp_state virtioscsi_online;
 static struct kmem_cache *virtscsi_cmd_cache;
 static mempool_t *virtscsi_cmd_pool;
 
@@ -766,6 +766,13 @@ static void virtscsi_target_destroy(struct scsi_target *starget)
        kfree(tgt);
 }
 
+static int virtscsi_map_queues(struct Scsi_Host *shost)
+{
+       struct virtio_scsi *vscsi = shost_priv(shost);
+
+       return blk_mq_virtio_map_queues(&shost->tag_set, vscsi->vdev, 2);
+}
+
 static struct scsi_host_template virtscsi_host_template_single = {
        .module = THIS_MODULE,
        .name = "Virtio SCSI HBA",
@@ -801,6 +808,7 @@ static struct scsi_host_template virtscsi_host_template_multi = {
        .use_clustering = ENABLE_CLUSTERING,
        .target_alloc = virtscsi_target_alloc,
        .target_destroy = virtscsi_target_destroy,
+       .map_queues = virtscsi_map_queues,
        .track_queue_depth = 1,
 };
 
@@ -817,80 +825,6 @@ static struct scsi_host_template virtscsi_host_template_multi = {
                virtio_cwrite(vdev, struct virtio_scsi_config, fld, &__val); \
        } while(0)
 
-static void __virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
-{
-       int i;
-       int cpu;
-
-       /* In multiqueue mode, when the number of cpu is equal
-        * to the number of request queues, we let the qeueues
-        * to be private to one cpu by setting the affinity hint
-        * to eliminate the contention.
-        */
-       if ((vscsi->num_queues == 1 ||
-            vscsi->num_queues != num_online_cpus()) && affinity) {
-               if (vscsi->affinity_hint_set)
-                       affinity = false;
-               else
-                       return;
-       }
-
-       if (affinity) {
-               i = 0;
-               for_each_online_cpu(cpu) {
-                       virtqueue_set_affinity(vscsi->req_vqs[i].vq, cpu);
-                       i++;
-               }
-
-               vscsi->affinity_hint_set = true;
-       } else {
-               for (i = 0; i < vscsi->num_queues; i++) {
-                       if (!vscsi->req_vqs[i].vq)
-                               continue;
-
-                       virtqueue_set_affinity(vscsi->req_vqs[i].vq, -1);
-               }
-
-               vscsi->affinity_hint_set = false;
-       }
-}
-
-static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
-{
-       get_online_cpus();
-       __virtscsi_set_affinity(vscsi, affinity);
-       put_online_cpus();
-}
-
-static int virtscsi_cpu_online(unsigned int cpu, struct hlist_node *node)
-{
-       struct virtio_scsi *vscsi = hlist_entry_safe(node, struct virtio_scsi,
-                                                    node);
-       __virtscsi_set_affinity(vscsi, true);
-       return 0;
-}
-
-static int virtscsi_cpu_notif_add(struct virtio_scsi *vi)
-{
-       int ret;
-
-       ret = cpuhp_state_add_instance(virtioscsi_online, &vi->node);
-       if (ret)
-               return ret;
-
-       ret = cpuhp_state_add_instance(CPUHP_VIRT_SCSI_DEAD, &vi->node_dead);
-       if (ret)
-               cpuhp_state_remove_instance(virtioscsi_online, &vi->node);
-       return ret;
-}
-
-static void virtscsi_cpu_notif_remove(struct virtio_scsi *vi)
-{
-       cpuhp_state_remove_instance_nocalls(virtioscsi_online, &vi->node);
-       cpuhp_state_remove_instance_nocalls(CPUHP_VIRT_SCSI_DEAD,
-                                           &vi->node_dead);
-}
-
 static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
                             struct virtqueue *vq)
 {
@@ -900,14 +834,8 @@ static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
 
 static void virtscsi_remove_vqs(struct virtio_device *vdev)
 {
-       struct Scsi_Host *sh = virtio_scsi_host(vdev);
-       struct virtio_scsi *vscsi = shost_priv(sh);
-
-       virtscsi_set_affinity(vscsi, false);
-
        /* Stop all the virtqueues. */
        vdev->config->reset(vdev);
-
        vdev->config->del_vqs(vdev);
 }
 
@@ -920,6 +848,7 @@ static int virtscsi_init(struct virtio_device *vdev,
        vq_callback_t **callbacks;
        const char **names;
        struct virtqueue **vqs;
+       struct irq_affinity desc = { .pre_vectors = 2 };
 
        num_vqs = vscsi->num_queues + VIRTIO_SCSI_VQ_BASE;
        vqs = kmalloc(num_vqs * sizeof(struct virtqueue *), GFP_KERNEL);
@@ -942,7 +871,7 @@ static int virtscsi_init(struct virtio_device *vdev,
 
        /* Discover virtqueues and write information to configuration.  */
        err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names,
-                       NULL);
+                       &desc);
        if (err)
                goto out;
 
@@ -1008,10 +937,6 @@ static int virtscsi_probe(struct virtio_device *vdev)
        if (err)
                goto virtscsi_init_failed;
 
-       err = virtscsi_cpu_notif_add(vscsi);
-       if (err)
-               goto scsi_add_host_failed;
-
        cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
        shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
        shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
@@ -1066,9 +991,6 @@ static void virtscsi_remove(struct virtio_device *vdev)
                virtscsi_cancel_event_work(vscsi);
 
        scsi_remove_host(shost);
-
-       virtscsi_cpu_notif_remove(vscsi);
-
        virtscsi_remove_vqs(vdev);
        scsi_host_put(shost);
 }
@@ -1076,10 +998,6 @@ static void virtscsi_remove(struct virtio_device *vdev)
 #ifdef CONFIG_PM_SLEEP
 static int virtscsi_freeze(struct virtio_device *vdev)
 {
-       struct Scsi_Host *sh = virtio_scsi_host(vdev);
-       struct virtio_scsi *vscsi = shost_priv(sh);
-
-       virtscsi_cpu_notif_remove(vscsi);
        virtscsi_remove_vqs(vdev);
        return 0;
 }
@@ -1094,11 +1012,6 @@ static int virtscsi_restore(struct virtio_device *vdev)
        if (err)
                return err;
 
-       err = virtscsi_cpu_notif_add(vscsi);
-       if (err) {
-               vdev->config->del_vqs(vdev);
-               return err;
-       }
        virtio_device_ready(vdev);
 
        if (virtio_has_feature(vdev, VIRTIO_SCSI_F_HOTPLUG))
@@ -1153,16 +1066,6 @@ static int __init init(void)
                pr_err("mempool_create() for virtscsi_cmd_pool failed\n");
                goto error;
        }
-       ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
-                                     "scsi/virtio:online",
-                                     virtscsi_cpu_online, NULL);
-       if (ret < 0)
-               goto error;
-       virtioscsi_online = ret;
-       ret = cpuhp_setup_state_multi(CPUHP_VIRT_SCSI_DEAD, "scsi/virtio:dead",
-                                     NULL, virtscsi_cpu_online);
-       if (ret)
-               goto error;
        ret = register_virtio_driver(&virtio_scsi_driver);
        if (ret < 0)
                goto error;
@@ -1178,17 +1081,12 @@ error:
                kmem_cache_destroy(virtscsi_cmd_cache);
                virtscsi_cmd_cache = NULL;
        }
-       if (virtioscsi_online)
-               cpuhp_remove_multi_state(virtioscsi_online);
-       cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);
        return ret;
 }
 
 static void __exit fini(void)
 {
        unregister_virtio_driver(&virtio_scsi_driver);
-       cpuhp_remove_multi_state(virtioscsi_online);
-       cpuhp_remove_multi_state(CPUHP_VIRT_SCSI_DEAD);
        mempool_destroy(virtscsi_cmd_pool);
        kmem_cache_destroy(virtscsi_cmd_cache);
 }

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 921acaaa16017979df0722fb9803b204d77c0be0..01aea80a503e9577efcd8793bbf2b60a6d3a611a 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -26,7 +26,6 @@ enum cpuhp_state {
        CPUHP_ARM_OMAP_WAKE_DEAD,
        CPUHP_IRQ_POLL_DEAD,
        CPUHP_BLOCK_SOFTIRQ_DEAD,
-       CPUHP_VIRT_SCSI_DEAD,
        CPUHP_ACPI_CPUDRV_DEAD,
        CPUHP_S390_PFAULT_DEAD,
        CPUHP_BLK_MQ_DEAD,