SUNRPC: Don't allow compiler optimisation of svc_xprt_release_slot()

Use READ_ONCE() to tell the compiler to not optimse away the read of
xprt->xpt_flags in svc_xprt_release_slot().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 4eb8fbf2508d..c3af1aaef551 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -363,9 +363,13 @@ static void svc_xprt_release_slot(struct svc_rqst *rqstp)
 
 static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
 {
-        if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
+        unsigned long xpt_flags;
+
+        xpt_flags = READ_ONCE(xprt->xpt_flags);
+
+        if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
                 return true;
-        if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) {
+        if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
                 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
                     svc_xprt_slots_in_range(xprt))
                         return true;