From 729749bb8da186e68d97d1b0439f0b1e0059c41d Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 13 Aug 2017 10:03:59 -0400 Subject: [PATCH] SUNRPC: Don't hold the transport lock across socket copy operations Instead add a mechanism to ensure that the request doesn't disappear from underneath us while copying from the socket. We do this by preventing xprt_release() from freeing the XDR buffers until the flag RPC_TASK_MSG_RECV has been cleared from the request. Signed-off-by: Trond Myklebust Reviewed-by: Chuck Lever --- include/linux/sunrpc/sched.h | 2 ++ include/linux/sunrpc/xprt.h | 2 ++ net/sunrpc/xprt.c | 43 ++++++++++++++++++++++++++++++++++++ net/sunrpc/xprtsock.c | 23 ++++++++++++++----- 4 files changed, 65 insertions(+), 5 deletions(-) diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h index 50a99a117da7..c1768f9d993b 100644 --- a/include/linux/sunrpc/sched.h +++ b/include/linux/sunrpc/sched.h @@ -139,6 +139,8 @@ struct rpc_task_setup { #define RPC_TASK_RUNNING 0 #define RPC_TASK_QUEUED 1 #define RPC_TASK_ACTIVE 2 +#define RPC_TASK_MSG_RECV 3 +#define RPC_TASK_MSG_RECV_WAIT 4 #define RPC_IS_RUNNING(t) test_bit(RPC_TASK_RUNNING, &(t)->tk_runstate) #define rpc_set_running(t) set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index eab1c749e192..65b9e0224753 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -372,6 +372,8 @@ void xprt_write_space(struct rpc_xprt *xprt); void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result); struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid); void xprt_complete_rqst(struct rpc_task *task, int copied); +void xprt_pin_rqst(struct rpc_rqst *req); +void xprt_unpin_rqst(struct rpc_rqst *req); void xprt_release_rqst_cong(struct rpc_task *task); void xprt_disconnect_done(struct rpc_xprt *xprt); void xprt_force_disconnect(struct rpc_xprt *xprt); diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 4654a9934269..3eb9ec16eec4 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -844,6 +844,48 @@ struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid) } EXPORT_SYMBOL_GPL(xprt_lookup_rqst); +/** + * xprt_pin_rqst - Pin a request on the transport receive list + * @req: Request to pin + * + * Caller must ensure this is atomic with the call to xprt_lookup_rqst() + * so should be holding the xprt transport lock. + */ +void xprt_pin_rqst(struct rpc_rqst *req) +{ + set_bit(RPC_TASK_MSG_RECV, &req->rq_task->tk_runstate); +} + +/** + * xprt_unpin_rqst - Unpin a request on the transport receive list + * @req: Request to pin + * + * Caller should be holding the xprt transport lock. + */ +void xprt_unpin_rqst(struct rpc_rqst *req) +{ + struct rpc_task *task = req->rq_task; + + clear_bit(RPC_TASK_MSG_RECV, &task->tk_runstate); + if (test_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate)) + wake_up_bit(&task->tk_runstate, RPC_TASK_MSG_RECV); +} + +static void xprt_wait_on_pinned_rqst(struct rpc_rqst *req) +__must_hold(&req->rq_xprt->transport_lock) +{ + struct rpc_task *task = req->rq_task; + + if (task && test_bit(RPC_TASK_MSG_RECV, &task->tk_runstate)) { + spin_unlock_bh(&req->rq_xprt->transport_lock); + set_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate); + wait_on_bit(&task->tk_runstate, RPC_TASK_MSG_RECV, + TASK_UNINTERRUPTIBLE); + clear_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate); + spin_lock_bh(&req->rq_xprt->transport_lock); + } +} + static void xprt_update_rtt(struct rpc_task *task) { struct rpc_rqst *req = task->tk_rqstp; @@ -1295,6 +1337,7 @@ void xprt_release(struct rpc_task *task) list_del(&req->rq_list); xprt->last_used = jiffies; xprt_schedule_autodisconnect(xprt); + xprt_wait_on_pinned_rqst(req); spin_unlock_bh(&xprt->transport_lock); if (req->rq_buffer) xprt->ops->buf_free(task); diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 4f154d388748..04dbc7027712 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -973,6 +973,8 @@ static void xs_local_data_read_skb(struct rpc_xprt *xprt, rovr = xprt_lookup_rqst(xprt, *xp); if (!rovr) goto out_unlock; + xprt_pin_rqst(rovr); + spin_unlock_bh(&xprt->transport_lock); task = rovr->rq_task; copied = rovr->rq_private_buf.buflen; @@ -981,11 +983,14 @@ static void xs_local_data_read_skb(struct rpc_xprt *xprt, if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) { dprintk("RPC: sk_buff copy failed\n"); - goto out_unlock; + spin_lock_bh(&xprt->transport_lock); + goto out_unpin; } + spin_lock_bh(&xprt->transport_lock); xprt_complete_rqst(task, copied); - +out_unpin: + xprt_unpin_rqst(rovr); out_unlock: spin_unlock_bh(&xprt->transport_lock); } @@ -1054,6 +1059,8 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt, rovr = xprt_lookup_rqst(xprt, *xp); if (!rovr) goto out_unlock; + xprt_pin_rqst(rovr); + spin_unlock_bh(&xprt->transport_lock); task = rovr->rq_task; if ((copied = rovr->rq_private_buf.buflen) > repsize) @@ -1062,14 +1069,17 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt, /* Suck it into the iovec, verify checksum if not done by hw. */ if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) { __UDPX_INC_STATS(sk, UDP_MIB_INERRORS); - goto out_unlock; + spin_lock_bh(&xprt->transport_lock); + goto out_unpin; } __UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS); + spin_lock_bh(&xprt->transport_lock); xprt_adjust_cwnd(xprt, task, copied); xprt_complete_rqst(task, copied); - +out_unpin: + xprt_unpin_rqst(rovr); out_unlock: spin_unlock_bh(&xprt->transport_lock); } @@ -1351,12 +1361,15 @@ static inline int xs_tcp_read_reply(struct rpc_xprt *xprt, spin_unlock_bh(&xprt->transport_lock); return -1; } + xprt_pin_rqst(req); + spin_unlock_bh(&xprt->transport_lock); xs_tcp_read_common(xprt, desc, req); + spin_lock_bh(&xprt->transport_lock); if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) xprt_complete_rqst(req->rq_task, transport->tcp_copied); - + xprt_unpin_rqst(req); spin_unlock_bh(&xprt->transport_lock); return 0; }