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path: root/drivers/xen/xenbus/xenbus_xs.c
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Diffstat (limited to 'drivers/xen/xenbus/xenbus_xs.c')
-rw-r--r--drivers/xen/xenbus/xenbus_xs.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index ddc18da61834..3a06eb699f33 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -191,8 +191,11 @@ static bool xenbus_ok(void)
static bool test_reply(struct xb_req_data *req)
{
- if (req->state == xb_req_state_got_reply || !xenbus_ok())
+ if (req->state == xb_req_state_got_reply || !xenbus_ok()) {
+ /* read req->state before all other fields */
+ virt_rmb();
return true;
+ }
/* Make sure to reread req->state each time. */
barrier();
@@ -202,7 +205,7 @@ static bool test_reply(struct xb_req_data *req)
static void *read_reply(struct xb_req_data *req)
{
- while (req->state != xb_req_state_got_reply) {
+ do {
wait_event(req->wq, test_reply(req));
if (!xenbus_ok())
@@ -216,7 +219,7 @@ static void *read_reply(struct xb_req_data *req)
if (req->err)
return ERR_PTR(req->err);
- }
+ } while (req->state != xb_req_state_got_reply);
return req->body;
}