diff options
| author | Jeff Layton <jlayton@poochiereds.net> | 2015-06-03 16:14:28 -0400 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-06-10 18:26:24 -0400 |
| commit | d6e971d8ecafee18ff9cc1ac646eb0817ab8b143 (patch) | |
| tree | d1a2a975cee7cbe10258081e2a2a781a95d15a8f /net | |
| parent | 264d1df3b34804a7d440d77771020f616a573528 (diff) | |
sunrpc: lock xprt before trying to set memalloc on the sockets
It's possible that we could race with a call to xs_reset_transport, in
which case the xprt->inet pointer could be zeroed out while we're
accessing it. Lock the xprt before we try to set memalloc on it.
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sunrpc/xprtsock.c | 35 |
1 files changed, 27 insertions, 8 deletions
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 31b856a2935c..e0efd8514886 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1959,11 +1959,22 @@ 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. + */ static void xs_set_memalloc(struct rpc_xprt *xprt) { struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt); + /* + * If there's no sock, then we have nothing to set. The + * reconnecting process will get it for us. + */ + if (!transport->inet) + return; if (atomic_read(&xprt->swapper)) sk_set_memalloc(transport->inet); } @@ -1978,11 +1989,15 @@ static void xs_set_memalloc(struct rpc_xprt *xprt) int xs_swapper_enable(struct rpc_xprt *xprt) { - struct sock_xprt *transport = container_of(xprt, struct sock_xprt, - xprt); + struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt); - if (atomic_inc_return(&xprt->swapper) == 1) - sk_set_memalloc(transport->inet); + 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) + sk_set_memalloc(xs->inet); + xprt_release_xprt(xprt, NULL); return 0; } @@ -1996,11 +2011,15 @@ xs_swapper_enable(struct rpc_xprt *xprt) void xs_swapper_disable(struct rpc_xprt *xprt) { - struct sock_xprt *transport = container_of(xprt, struct sock_xprt, - xprt); + struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt); - if (atomic_dec_and_test(&xprt->swapper)) - sk_clear_memalloc(transport->inet); + if (!atomic_dec_and_test(&xprt->swapper)) + return; + if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE)) + return; + if (xs->inet) + sk_clear_memalloc(xs->inet); + xprt_release_xprt(xprt, NULL); } #else static void xs_set_memalloc(struct rpc_xprt *xprt) |