Commit d7ffde35 authored Jun 26, 2012 by Jens Freimann Committed by David S. Miller Jun 26, 2012

vhost: use USER_DS in vhost_worker thread



On some architectures address spaces are set up in a way that this is
not necessary to work properly but on some others (like s390) it is.
Make sure we operate on the user address space to allow copy_xxx_user()
from the vhost_worker() thread by setting it explicitly before calling
use_mm() and revert it after unuse_mm().

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 57efd44c

drivers/vhost/vhost.c

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -191,7 +191,9 @@ static int vhost_worker(void *data)
	struct vhost_dev *dev = data;		struct vhost_dev *dev = data;
	struct vhost_work *work = NULL;		struct vhost_work *work = NULL;
	unsigned uninitialized_var(seq);		unsigned uninitialized_var(seq);
			mm_segment_t oldfs = get_fs();

			set_fs(USER_DS);
	use_mm(dev->mm);		use_mm(dev->mm);

	for (;;) {		for (;;) {
	@@ -229,6 +231,7 @@ static int vhost_worker(void *data)

	}		}
	unuse_mm(dev->mm);		unuse_mm(dev->mm);
			set_fs(oldfs);
	return 0;		return 0;
	}		}