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 <trond.myklebust@primarydata.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
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@ -139,6 +139,8 @@ struct rpc_task_setup {
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#define RPC_TASK_RUNNING 0
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#define RPC_TASK_QUEUED 1
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#define RPC_TASK_ACTIVE 2
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#define RPC_TASK_MSG_RECV 3
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#define RPC_TASK_MSG_RECV_WAIT 4
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#define RPC_IS_RUNNING(t) test_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
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#define rpc_set_running(t) set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
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@ -372,6 +372,8 @@ void xprt_write_space(struct rpc_xprt *xprt);
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void xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
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struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
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void xprt_complete_rqst(struct rpc_task *task, int copied);
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void xprt_pin_rqst(struct rpc_rqst *req);
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void xprt_unpin_rqst(struct rpc_rqst *req);
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void xprt_release_rqst_cong(struct rpc_task *task);
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void xprt_disconnect_done(struct rpc_xprt *xprt);
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void xprt_force_disconnect(struct rpc_xprt *xprt);
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@ -844,6 +844,48 @@ struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid)
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}
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EXPORT_SYMBOL_GPL(xprt_lookup_rqst);
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/**
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* xprt_pin_rqst - Pin a request on the transport receive list
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* @req: Request to pin
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*
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* Caller must ensure this is atomic with the call to xprt_lookup_rqst()
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* so should be holding the xprt transport lock.
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*/
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void xprt_pin_rqst(struct rpc_rqst *req)
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{
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set_bit(RPC_TASK_MSG_RECV, &req->rq_task->tk_runstate);
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}
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/**
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* xprt_unpin_rqst - Unpin a request on the transport receive list
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* @req: Request to pin
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*
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* Caller should be holding the xprt transport lock.
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*/
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void xprt_unpin_rqst(struct rpc_rqst *req)
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{
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struct rpc_task *task = req->rq_task;
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clear_bit(RPC_TASK_MSG_RECV, &task->tk_runstate);
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if (test_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate))
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wake_up_bit(&task->tk_runstate, RPC_TASK_MSG_RECV);
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}
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static void xprt_wait_on_pinned_rqst(struct rpc_rqst *req)
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__must_hold(&req->rq_xprt->transport_lock)
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{
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struct rpc_task *task = req->rq_task;
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if (task && test_bit(RPC_TASK_MSG_RECV, &task->tk_runstate)) {
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spin_unlock_bh(&req->rq_xprt->transport_lock);
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set_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate);
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wait_on_bit(&task->tk_runstate, RPC_TASK_MSG_RECV,
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TASK_UNINTERRUPTIBLE);
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clear_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate);
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spin_lock_bh(&req->rq_xprt->transport_lock);
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}
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}
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static void xprt_update_rtt(struct rpc_task *task)
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{
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struct rpc_rqst *req = task->tk_rqstp;
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@ -1295,6 +1337,7 @@ void xprt_release(struct rpc_task *task)
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list_del(&req->rq_list);
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xprt->last_used = jiffies;
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xprt_schedule_autodisconnect(xprt);
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xprt_wait_on_pinned_rqst(req);
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spin_unlock_bh(&xprt->transport_lock);
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if (req->rq_buffer)
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xprt->ops->buf_free(task);
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@ -973,6 +973,8 @@ static void xs_local_data_read_skb(struct rpc_xprt *xprt,
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rovr = xprt_lookup_rqst(xprt, *xp);
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if (!rovr)
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goto out_unlock;
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xprt_pin_rqst(rovr);
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spin_unlock_bh(&xprt->transport_lock);
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task = rovr->rq_task;
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copied = rovr->rq_private_buf.buflen;
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@ -981,11 +983,14 @@ static void xs_local_data_read_skb(struct rpc_xprt *xprt,
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if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
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dprintk("RPC: sk_buff copy failed\n");
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goto out_unlock;
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spin_lock_bh(&xprt->transport_lock);
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goto out_unpin;
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}
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spin_lock_bh(&xprt->transport_lock);
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xprt_complete_rqst(task, copied);
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out_unpin:
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xprt_unpin_rqst(rovr);
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out_unlock:
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spin_unlock_bh(&xprt->transport_lock);
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}
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@ -1054,6 +1059,8 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
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rovr = xprt_lookup_rqst(xprt, *xp);
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if (!rovr)
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goto out_unlock;
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xprt_pin_rqst(rovr);
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spin_unlock_bh(&xprt->transport_lock);
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task = rovr->rq_task;
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if ((copied = rovr->rq_private_buf.buflen) > repsize)
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@ -1062,14 +1069,17 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
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/* Suck it into the iovec, verify checksum if not done by hw. */
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if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
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__UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
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goto out_unlock;
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spin_lock_bh(&xprt->transport_lock);
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goto out_unpin;
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}
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__UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
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spin_lock_bh(&xprt->transport_lock);
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xprt_adjust_cwnd(xprt, task, copied);
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xprt_complete_rqst(task, copied);
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out_unpin:
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xprt_unpin_rqst(rovr);
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out_unlock:
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spin_unlock_bh(&xprt->transport_lock);
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}
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@ -1351,12 +1361,15 @@ static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
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spin_unlock_bh(&xprt->transport_lock);
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return -1;
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}
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xprt_pin_rqst(req);
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spin_unlock_bh(&xprt->transport_lock);
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xs_tcp_read_common(xprt, desc, req);
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spin_lock_bh(&xprt->transport_lock);
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if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
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xprt_complete_rqst(req->rq_task, transport->tcp_copied);
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xprt_unpin_rqst(req);
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spin_unlock_bh(&xprt->transport_lock);
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return 0;
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}
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