2018-12-17 16:25:07

by Vasily Averin

Subject: [PATCH 2/4] nfs: remove sv_bc_enabled using in svc_is_backchannel()

serv->sv_bc_xprt cannot be used as pointer,
serv is global structure, but sv_bc_xprt is assigned per-netnamespace

The only user of this field is svc_is_backchannel() where it is used
not as pointer but as mark of backchannel-compatible servers.

Convert netns-unsafe xprt pointer to simple boolean mark,
Hope it helps to prevent misuse of sv_bc_xpr in future.

Signed-off-by: Vasily Averin <[email protected]>
---
include/linux/sunrpc/bc_xprt.h | 10 ++++------
include/linux/sunrpc/svc.h | 2 +-
net/sunrpc/svcsock.c | 2 +-
net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 +-
4 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h
index 28721cf73ec3..4e8c773d02be 100644
--- a/include/linux/sunrpc/bc_xprt.h
+++ b/include/linux/sunrpc/bc_xprt.h
@@ -47,11 +47,9 @@ void xprt_free_bc_rqst(struct rpc_rqst *req);
/*
* Determine if a shared backchannel is in use
*/
-static inline int svc_is_backchannel(const struct svc_rqst *rqstp)
+static inline bool svc_is_backchannel(const struct svc_rqst *rqstp)
{
- if (rqstp->rq_server->sv_bc_xprt)
- return 1;
- return 0;
+ return rqstp->rq_server->sv_bc_enabled;
}
#else /* CONFIG_SUNRPC_BACKCHANNEL */
static inline int xprt_setup_backchannel(struct rpc_xprt *xprt,
@@ -60,9 +58,9 @@ static inline int xprt_setup_backchannel(struct rpc_xprt *xprt,
return 0;
}

-static inline int svc_is_backchannel(const struct svc_rqst *rqstp)
+static inline bool svc_is_backchannel(const struct svc_rqst *rqstp)
{
- return 0;
+ return false;
}

static inline void xprt_free_bc_request(struct rpc_rqst *req)
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 73e130a840ce..bf21609160c1 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -109,7 +109,7 @@ struct svc_serv {
spinlock_t sv_cb_lock; /* protects the svc_cb_list */
wait_queue_head_t sv_cb_waitq; /* sleep here if there are no
* entries in the svc_cb_list */
- struct svc_xprt *sv_bc_xprt; /* callback on fore channel */
+ bool sv_bc_enabled; /* server uses backchannel */
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
};

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 986f3ed7d1a2..5a6b3ba555c7 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1623,7 +1623,7 @@ static struct svc_xprt *svc_bc_create_socket(struct svc_serv *serv,
svc_xprt_init(net, &svc_tcp_bc_class, xprt, serv);
set_bit(XPT_CONG_CTRL, &svsk->sk_xprt.xpt_flags);

- serv->sv_bc_xprt = xprt;
+ serv->sv_bc_enabled = true;

return xprt;
}
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 2f7ec8912f49..88694048d5c0 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -136,7 +136,7 @@ static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *serv,

svc_xprt_init(net, &svc_rdma_bc_class, xprt, serv);
set_bit(XPT_CONG_CTRL, &xprt->xpt_flags);
- serv->sv_bc_xprt = xprt;
+ serv->sv_bc_enabled = true;

dprintk("svcrdma: %s(%p)\n", __func__, xprt);
return xprt;
--
2.17.1

2018-12-17 17:52:19

by Jeff Layton

Subject: Re: [PATCH 2/4] nfs: remove sv_bc_enabled using in svc_is_backchannel()

On Mon, 2018-12-17 at 19:25 +0300, Vasily Averin wrote:
> serv->sv_bc_xprt cannot be used as pointer,
> serv is global structure, but sv_bc_xprt is assigned per-netnamespace
>
> The only user of this field is svc_is_backchannel() where it is used
> not as pointer but as mark of backchannel-compatible servers.
>
> Convert netns-unsafe xprt pointer to simple boolean mark,
> Hope it helps to prevent misuse of sv_bc_xpr in future.
>
> Signed-off-by: Vasily Averin <[email protected]>
> ---
> include/linux/sunrpc/bc_xprt.h | 10 ++++------
> include/linux/sunrpc/svc.h | 2 +-
> net/sunrpc/svcsock.c | 2 +-
> net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 +-
> 4 files changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h
> index 28721cf73ec3..4e8c773d02be 100644
> --- a/include/linux/sunrpc/bc_xprt.h
> +++ b/include/linux/sunrpc/bc_xprt.h
> @@ -47,11 +47,9 @@ void xprt_free_bc_rqst(struct rpc_rqst *req);
> /*
> * Determine if a shared backchannel is in use
> */
> -static inline int svc_is_backchannel(const struct svc_rqst *rqstp)
> +static inline bool svc_is_backchannel(const struct svc_rqst *rqstp)
> {
> - if (rqstp->rq_server->sv_bc_xprt)
> - return 1;
> - return 0;
> + return rqstp->rq_server->sv_bc_enabled;
> }
> #else /* CONFIG_SUNRPC_BACKCHANNEL */
> static inline int xprt_setup_backchannel(struct rpc_xprt *xprt,
> @@ -60,9 +58,9 @@ static inline int xprt_setup_backchannel(struct rpc_xprt *xprt,
> return 0;
> }
>
> -static inline int svc_is_backchannel(const struct svc_rqst *rqstp)
> +static inline bool svc_is_backchannel(const struct svc_rqst *rqstp)
> {
> - return 0;
> + return false;
> }
>
> static inline void xprt_free_bc_request(struct rpc_rqst *req)
> diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
> index 73e130a840ce..bf21609160c1 100644
> --- a/include/linux/sunrpc/svc.h
> +++ b/include/linux/sunrpc/svc.h
> @@ -109,7 +109,7 @@ struct svc_serv {
> spinlock_t sv_cb_lock; /* protects the svc_cb_list */
> wait_queue_head_t sv_cb_waitq; /* sleep here if there are no
> * entries in the svc_cb_list */
> - struct svc_xprt *sv_bc_xprt; /* callback on fore channel */
> + bool sv_bc_enabled; /* server uses backchannel */
> #endif /* CONFIG_SUNRPC_BACKCHANNEL */
> };
>
> diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
> index 986f3ed7d1a2..5a6b3ba555c7 100644
> --- a/net/sunrpc/svcsock.c
> +++ b/net/sunrpc/svcsock.c
> @@ -1623,7 +1623,7 @@ static struct svc_xprt *svc_bc_create_socket(struct svc_serv *serv,
> svc_xprt_init(net, &svc_tcp_bc_class, xprt, serv);
> set_bit(XPT_CONG_CTRL, &svsk->sk_xprt.xpt_flags);
>
> - serv->sv_bc_xprt = xprt;
> + serv->sv_bc_enabled = true;
>
> return xprt;
> }
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> index 2f7ec8912f49..88694048d5c0 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
> @@ -136,7 +136,7 @@ static struct svc_xprt *svc_rdma_bc_create(struct svc_serv *serv,
>
> svc_xprt_init(net, &svc_rdma_bc_class, xprt, serv);
> set_bit(XPT_CONG_CTRL, &xprt->xpt_flags);
> - serv->sv_bc_xprt = xprt;
> + serv->sv_bc_enabled = true;
>
> dprintk("svcrdma: %s(%p)\n", __func__, xprt);
> return xprt;

Reviewed-by: Jeff Layton <[email protected]>