[PATCH v2 7/9] virtio-mem: factor out hotplug specifics from virtio_mem_probe() into virtio_mem_init_hotplug()

[David Hildenbrand <david@xxxxxxxxxx>]

Let's prepare for a new virtio-mem kdump mode in which we don't actually
hot(un)plug any memory but only observe the state of device blocks.

Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
 drivers/virtio/virtio_mem.c | 87 +++++++++++++++++++------------------
 1 file changed, 45 insertions(+), 42 deletions(-)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 2ba7e8d6ba8d..1be3ee7f684d 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -260,6 +260,8 @@ static void virtio_mem_fake_offline_going_offline(unsigned 
long pfn,
 static void virtio_mem_fake_offline_cancel_offline(unsigned long pfn,
                                                   unsigned long nr_pages);
 static void virtio_mem_retry(struct virtio_mem *vm);
+static int virtio_mem_create_resource(struct virtio_mem *vm);
+static void virtio_mem_delete_resource(struct virtio_mem *vm);
 
 /*
  * Register a virtio-mem device so it will be considered for the online_page
@@ -2395,7 +2397,8 @@ static int virtio_mem_init_vq(struct virtio_mem *vm)
 static int virtio_mem_init_hotplug(struct virtio_mem *vm)
 {
        const struct range pluggable_range = mhp_get_pluggable_range(true);
-       uint64_t sb_size, addr;
+       uint64_t unit_pages, sb_size, addr;
+       int rc;
 
        /* bad device setup - warn only */
        if (!IS_ALIGNED(vm->addr, memory_block_size_bytes()))
@@ -2474,7 +2477,48 @@ static int virtio_mem_init_hotplug(struct virtio_mem *vm)
                dev_info(&vm->vdev->dev, "big block size: 0x%llx",
                         (unsigned long long)vm->bbm.bb_size);
 
+       /* create the parent resource for all memory */
+       rc = virtio_mem_create_resource(vm);
+       if (rc)
+               return rc;
+
+       /* use a single dynamic memory group to cover the whole memory device */
+       if (vm->in_sbm)
+               unit_pages = PHYS_PFN(memory_block_size_bytes());
+       else
+               unit_pages = PHYS_PFN(vm->bbm.bb_size);
+       rc = memory_group_register_dynamic(vm->nid, unit_pages);
+       if (rc < 0)
+               goto out_del_resource;
+       vm->mgid = rc;
+
+       /*
+        * If we still have memory plugged, we have to unplug all memory first.
+        * Registering our parent resource makes sure that this memory isn't
+        * actually in use (e.g., trying to reload the driver).
+        */
+       if (vm->plugged_size) {
+               vm->unplug_all_required = true;
+               dev_info(&vm->vdev->dev, "unplugging all memory is required\n");
+       }
+
+       /* register callbacks */
+       vm->memory_notifier.notifier_call = virtio_mem_memory_notifier_cb;
+       rc = register_memory_notifier(&vm->memory_notifier);
+       if (rc)
+               goto out_unreg_group;
+       rc = register_virtio_mem_device(vm);
+       if (rc)
+               goto out_unreg_mem;
+
        return 0;
+out_unreg_mem:
+       unregister_memory_notifier(&vm->memory_notifier);
+out_unreg_group:
+       memory_group_unregister(vm->mgid);
+out_del_resource:
+       virtio_mem_delete_resource(vm);
+       return rc;
 }
 
 static int virtio_mem_init(struct virtio_mem *vm)
@@ -2578,7 +2622,6 @@ static bool virtio_mem_has_memory_added(struct virtio_mem 
*vm)
 static int virtio_mem_probe(struct virtio_device *vdev)
 {
        struct virtio_mem *vm;
-       uint64_t unit_pages;
        int rc;
 
        BUILD_BUG_ON(sizeof(struct virtio_mem_req) != 24);
@@ -2608,40 +2651,6 @@ static int virtio_mem_probe(struct virtio_device *vdev)
        if (rc)
                goto out_del_vq;
 
-       /* create the parent resource for all memory */
-       rc = virtio_mem_create_resource(vm);
-       if (rc)
-               goto out_del_vq;
-
-       /* use a single dynamic memory group to cover the whole memory device */
-       if (vm->in_sbm)
-               unit_pages = PHYS_PFN(memory_block_size_bytes());
-       else
-               unit_pages = PHYS_PFN(vm->bbm.bb_size);
-       rc = memory_group_register_dynamic(vm->nid, unit_pages);
-       if (rc < 0)
-               goto out_del_resource;
-       vm->mgid = rc;
-
-       /*
-        * If we still have memory plugged, we have to unplug all memory first.
-        * Registering our parent resource makes sure that this memory isn't
-        * actually in use (e.g., trying to reload the driver).
-        */
-       if (vm->plugged_size) {
-               vm->unplug_all_required = true;
-               dev_info(&vm->vdev->dev, "unplugging all memory is required\n");
-       }
-
-       /* register callbacks */
-       vm->memory_notifier.notifier_call = virtio_mem_memory_notifier_cb;
-       rc = register_memory_notifier(&vm->memory_notifier);
-       if (rc)
-               goto out_unreg_group;
-       rc = register_virtio_mem_device(vm);
-       if (rc)
-               goto out_unreg_mem;
-
        virtio_device_ready(vdev);
 
        /* trigger a config update to start processing the requested_size */
@@ -2649,12 +2658,6 @@ static int virtio_mem_probe(struct virtio_device *vdev)
        queue_work(system_freezable_wq, &vm->wq);
 
        return 0;
-out_unreg_mem:
-       unregister_memory_notifier(&vm->memory_notifier);
-out_unreg_group:
-       memory_group_unregister(vm->mgid);
-out_del_resource:
-       virtio_mem_delete_resource(vm);
 out_del_vq:
        vdev->config->del_vqs(vdev);
 out_free_vm:
-- 
2.31.1