[PATCH v4 7/9] vdpa_sim: use kthread worker

[Stefano Garzarella <sgarzare@xxxxxxxxxx>]

Let's use our own kthread to run device jobs.
This allows us more flexibility, especially we can attach the kthread
to the user address space when vDPA uses user's VA.

Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---

Notes:
    v3:
    - fix `dev` not initialized in the error path [Simon Horman]

 drivers/vdpa/vdpa_sim/vdpa_sim.h |  3 ++-
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 19 +++++++++++++------
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index acee20faaf6a..ce83f9130a5d 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -57,7 +57,8 @@ struct vdpasim_dev_attr {
 struct vdpasim {
 	struct vdpa_device vdpa;
 	struct vdpasim_virtqueue *vqs;
-	struct work_struct work;
+	struct kthread_worker *worker;
+	struct kthread_work work;
 	struct vdpasim_dev_attr dev_attr;
 	/* spinlock to synchronize virtqueue state */
 	spinlock_t lock;
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 2df5227e0b62..bd9f9054de94 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -11,8 +11,8 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/kthread.h>
 #include <linux/slab.h>
-#include <linux/sched.h>
 #include <linux/dma-map-ops.h>
 #include <linux/vringh.h>
 #include <linux/vdpa.h>
@@ -127,7 +127,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
 static const struct vdpa_config_ops vdpasim_config_ops;
 static const struct vdpa_config_ops vdpasim_batch_config_ops;
 
-static void vdpasim_work_fn(struct work_struct *work)
+static void vdpasim_work_fn(struct kthread_work *work)
 {
 	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
 
@@ -170,11 +170,17 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
 
 	vdpasim = vdpa_to_sim(vdpa);
 	vdpasim->dev_attr = *dev_attr;
-	INIT_WORK(&vdpasim->work, vdpasim_work_fn);
+	dev = &vdpasim->vdpa.dev;
+
+	kthread_init_work(&vdpasim->work, vdpasim_work_fn);
+	vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s",
+						dev_attr->name);
+	if (IS_ERR(vdpasim->worker))
+		goto err_iommu;
+
 	spin_lock_init(&vdpasim->lock);
 	spin_lock_init(&vdpasim->iommu_lock);
 
-	dev = &vdpasim->vdpa.dev;
 	dev->dma_mask = &dev->coherent_dma_mask;
 	if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)))
 		goto err_iommu;
@@ -223,7 +229,7 @@ EXPORT_SYMBOL_GPL(vdpasim_create);
 
 void vdpasim_schedule_work(struct vdpasim *vdpasim)
 {
-	schedule_work(&vdpasim->work);
+	kthread_queue_work(vdpasim->worker, &vdpasim->work);
 }
 EXPORT_SYMBOL_GPL(vdpasim_schedule_work);
 
@@ -623,7 +629,8 @@ static void vdpasim_free(struct vdpa_device *vdpa)
 	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 	int i;
 
-	cancel_work_sync(&vdpasim->work);
+	kthread_cancel_work_sync(&vdpasim->work);
+	kthread_destroy_worker(vdpasim->worker);
 
 	for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
 		vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov);
-- 
2.39.2