From d7ffde35e31a81100d2d0d2c4013cbf527bb32ea Mon Sep 17 00:00:00 2001 From: Jens Freimann Date: Tue, 26 Jun 2012 00:59:58 +0000 Subject: [PATCH] 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 Signed-off-by: Christian Borntraeger Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/vhost/vhost.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 94dbd25caa30..112156f68afb 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -191,7 +191,9 @@ static int vhost_worker(void *data) struct vhost_dev *dev = data; struct vhost_work *work = NULL; unsigned uninitialized_var(seq); + mm_segment_t oldfs = get_fs(); + set_fs(USER_DS); use_mm(dev->mm); for (;;) { @@ -229,6 +231,7 @@ static int vhost_worker(void *data) } unuse_mm(dev->mm); + set_fs(oldfs); return 0; }