It is not in general safe to wait for XPRT_LOCKED to clear.
A wakeup is only sent when
- connection completes
- sock close completes
so during normal operations, this can wait indefinitely.
The event we need to protect against is ->inet being set to NULL, and
that happens under the recv_mutex lock.
So drop the handlign of XPRT_LOCKED and use recv_mutex instead.
Signed-off-by: NeilBrown <[email protected]>
---
net/sunrpc/xprtsock.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 61d3293f1d68..7e39f87cde2d 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1936,9 +1936,9 @@ static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
#if IS_ENABLED(CONFIG_SUNRPC_SWAP)
/*
- * Note that this should be called with XPRT_LOCKED held (or when we otherwise
- * know that we have exclusive access to the socket), to guard against
- * races with xs_reset_transport.
+ * Note that this should be called with XPRT_LOCKED held, or recv_mutex
+ * held, or when we otherwise know that we have exclusive access to the
+ * socket, to guard against races with xs_reset_transport.
*/
static void xs_set_memalloc(struct rpc_xprt *xprt)
{
@@ -1967,13 +1967,11 @@ xs_enable_swap(struct rpc_xprt *xprt)
{
struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
- if (atomic_inc_return(&xprt->swapper) != 1)
- return 0;
- if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
- return -ERESTARTSYS;
- if (xs->inet)
+ mutex_lock(&xs->recv_mutex);
+ if (atomic_inc_return(&xprt->swapper) == 1 &&
+ xs->inet)
sk_set_memalloc(xs->inet);
- xprt_release_xprt(xprt, NULL);
+ mutex_unlock(&xs->recv_mutex);
return 0;
}
@@ -1989,13 +1987,11 @@ xs_disable_swap(struct rpc_xprt *xprt)
{
struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
- if (!atomic_dec_and_test(&xprt->swapper))
- return;
- if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))
- return;
- if (xs->inet)
+ mutex_lock(&xs->recv_mutex);
+ if (atomic_dec_and_test(&xprt->swapper) &&
+ xs->inet)
sk_clear_memalloc(xs->inet);
- xprt_release_xprt(xprt, NULL);
+ mutex_unlock(&xs->recv_mutex);
}
#else
static void xs_set_memalloc(struct rpc_xprt *xprt)