Finally add ioctl to allow userspace to create additional workers
For now only allow to increase the number of workers
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@xxxxxxxxxxxxx>
---
drivers/vhost/vhost.c | 32 +++++++++++++++++++++++++++++++-
include/uapi/linux/vhost.h | 9 +++++++++
2 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 219ad453ca27..09e3c4b1bd05 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -648,6 +648,25 @@ static int vhost_add_worker(struct vhost_dev *dev)
return err;
}
+static int vhost_set_workers(struct vhost_dev *dev, int n)
+{
+ int i, ret;
+
+ if (n > dev->nvqs)
+ n = dev->nvqs;
+
+ if (n > VHOST_MAX_WORKERS)
+ n = VHOST_MAX_WORKERS;
+
+ for (i = 0; i < n - dev->nworkers ; i++) {
+ ret = vhost_add_worker(dev);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
/* Caller should have device mutex */
long vhost_dev_set_owner(struct vhost_dev *dev)
{
@@ -1821,7 +1840,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
struct eventfd_ctx *ctx;
u64 p;
long r;
- int i, fd;
+ int i, fd, n;
/* If you are not the owner, you can become one */
if (ioctl == VHOST_SET_OWNER) {
@@ -1878,6 +1897,17 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
if (ctx)
eventfd_ctx_put(ctx);
break;
+ case VHOST_SET_NWORKERS:
+ r = get_user(n, (int __user *)argp);
+ if (r < 0)
+ break;
+ if (n < d->nworkers) {
+ r = -EINVAL;
+ break;
+ }
+
+ r = vhost_set_workers(d, n);
+ break;
default:
r = -ENOIOCTLCMD;
break;
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index 56a709e31709..f78cec410460 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -71,6 +71,15 @@
#define VHOST_SET_VRING_ENDIAN _IOW(VHOST_VIRTIO, 0x13, struct vhost_vring_state)
#define VHOST_GET_VRING_ENDIAN _IOW(VHOST_VIRTIO, 0x14, struct vhost_vring_state)
+/* Set number of vhost workers
+ * Currently nuber of vhost workers can only be increased.
+ * All workers are freed upon reset.
+ * If the value is too big it is silently truncated to the maximum number of
+ * supported vhost workers
+ * Even if the error is returned it is possible that some workers were created
+ */
+#define VHOST_SET_NWORKERS _IOW(VHOST_VIRTIO, 0x1F, int)
+
/* The following ioctls use eventfd file descriptors to signal and poll
* for events. */
--
2.31.1
