Commit 935cdee7 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

vhost: avoid backend flush on vring ops 



vring changes already do a flush internally where appropriate, so we do
not need a second flush.

It's currently not very expensive but a follow-up patch makes flush more
heavy-weight, so remove the extra flush here to avoid regressing
performance if call or kick fds are changed on data path.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 4a7d6455

drivers/vhost/net.c

+5 −2
Original line number Original line Diff line number Diff line
@@ -942,7 +942,10 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 
		return vhost_net_reset_owner(n);

		return vhost_net_reset_owner(n);

	default:

	default:

		mutex_lock(&n->dev.mutex);

		mutex_lock(&n->dev.mutex);

		r = vhost_dev_ioctl(&n->dev, ioctl, arg);

		r = vhost_dev_ioctl(&n->dev, ioctl, argp);

		if (r == -ENOIOCTLCMD)

			r = vhost_vring_ioctl(&n->dev, ioctl, argp);

		else

			vhost_net_flush(n);

			vhost_net_flush(n);

		mutex_unlock(&n->dev.mutex);

		mutex_unlock(&n->dev.mutex);

		return r;

		return r;

drivers/vhost/tcm_vhost.c

+4 −1
Original line number Original line Diff line number Diff line
@@ -970,7 +970,10 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl, 
		return vhost_scsi_set_features(vs, features);

		return vhost_scsi_set_features(vs, features);

	default:

	default:

		mutex_lock(&vs->dev.mutex);

		mutex_lock(&vs->dev.mutex);

		r = vhost_dev_ioctl(&vs->dev, ioctl, arg);

		r = vhost_dev_ioctl(&vs->dev, ioctl, argp);

		/* TODO: flush backend after dev ioctl. */

		if (r == -ENOIOCTLCMD)

			r = vhost_vring_ioctl(&vs->dev, ioctl, argp);

		mutex_unlock(&vs->dev.mutex);

		mutex_unlock(&vs->dev.mutex);

		return r;

		return r;

	}

	}

drivers/vhost/vhost.c

+3 −4
Original line number Original line Diff line number Diff line
@@ -607,7 +607,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) 
	return 0;

	return 0;

}

}





static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp)

long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)

{

{

	struct file *eventfp, *filep = NULL;

	struct file *eventfp, *filep = NULL;

	bool pollstart = false, pollstop = false;

	bool pollstart = false, pollstop = false;
@@ -802,9 +802,8 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) 
}

}





/* Caller must have device mutex */

/* Caller must have device mutex */

long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg)

long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)

{

{

	void __user *argp = (void __user *)arg;

	struct file *eventfp, *filep = NULL;

	struct file *eventfp, *filep = NULL;

	struct eventfd_ctx *ctx = NULL;

	struct eventfd_ctx *ctx = NULL;

	u64 p;

	u64 p;
@@ -875,7 +874,7 @@ long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) 
			fput(filep);

			fput(filep);

		break;

		break;

	default:

	default:

		r = vhost_set_vring(d, ioctl, argp);

		r = -ENOIOCTLCMD;

		break;

		break;

	}

	}

done:

done:

drivers/vhost/vhost.h

+2 −1
Original line number Original line Diff line number Diff line
@@ -164,7 +164,8 @@ long vhost_dev_check_owner(struct vhost_dev *); 
long vhost_dev_reset_owner(struct vhost_dev *);

long vhost_dev_reset_owner(struct vhost_dev *);

void vhost_dev_cleanup(struct vhost_dev *, bool locked);

void vhost_dev_cleanup(struct vhost_dev *, bool locked);

void vhost_dev_stop(struct vhost_dev *);

void vhost_dev_stop(struct vhost_dev *);

long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);

long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);

long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);

int vhost_vq_access_ok(struct vhost_virtqueue *vq);

int vhost_vq_access_ok(struct vhost_virtqueue *vq);

int vhost_log_access_ok(struct vhost_dev *);

int vhost_log_access_ok(struct vhost_dev *);

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