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| author | Chuck Lever | 2016-03-04 17:28:27 +0100 |
|---|---|---|
| committer | Anna Schumaker | 2016-03-14 19:56:01 +0100 |
| commit | 23826c7aeac7e333bfee6f10a3407a23c58b6147 (patch) | |
| tree | eeb5fe145b13b537658bb346e6dd958eaeb5e6d6 /net/sunrpc/xprtrdma/verbs.c | |
| parent | xprtrdma: Properly handle RDMA_ERROR replies (diff) | |
| download | kernel-qcow2-linux-23826c7aeac7e333bfee6f10a3407a23c58b6147.tar.gz kernel-qcow2-linux-23826c7aeac7e333bfee6f10a3407a23c58b6147.tar.xz kernel-qcow2-linux-23826c7aeac7e333bfee6f10a3407a23c58b6147.zip | |
xprtrdma: Serialize credit accounting again
Commit fe97b47cd623 ("xprtrdma: Use workqueue to process RPC/RDMA
replies") replaced the reply tasklet with a workqueue that allows
RPC replies to be processed in parallel. Thus the credit values in
RPC-over-RDMA replies can be applied in a different order than in
which the server sent them.
To fix this, revert commit eba8ff660b2d ("xprtrdma: Move credit
update to RPC reply handler"). Reverting is done by hand to
accommodate code changes that have occurred since then.
Fixes: fe97b47cd623 ("xprtrdma: Use workqueue to process . . .")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net/sunrpc/xprtrdma/verbs.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/verbs.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 878f1bfb1db9..fc1ef5f144b8 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -190,6 +190,28 @@ rpcrdma_receive_worker(struct work_struct *work) rpcrdma_reply_handler(rep); } +/* Perform basic sanity checking to avoid using garbage + * to update the credit grant value. + */ +static void +rpcrdma_update_granted_credits(struct rpcrdma_rep *rep) +{ + struct rpcrdma_msg *rmsgp = rdmab_to_msg(rep->rr_rdmabuf); + struct rpcrdma_buffer *buffer = &rep->rr_rxprt->rx_buf; + u32 credits; + + if (rep->rr_len < RPCRDMA_HDRLEN_ERR) + return; + + credits = be32_to_cpu(rmsgp->rm_credit); + if (credits == 0) + credits = 1; /* don't deadlock */ + else if (credits > buffer->rb_max_requests) + credits = buffer->rb_max_requests; + + atomic_set(&buffer->rb_credits, credits); +} + static void rpcrdma_recvcq_process_wc(struct ib_wc *wc) { @@ -211,7 +233,8 @@ rpcrdma_recvcq_process_wc(struct ib_wc *wc) ib_dma_sync_single_for_cpu(rep->rr_device, rdmab_addr(rep->rr_rdmabuf), rep->rr_len, DMA_FROM_DEVICE); - prefetch(rdmab_to_msg(rep->rr_rdmabuf)); + + rpcrdma_update_granted_credits(rep); out_schedule: queue_work(rpcrdma_receive_wq, &rep->rr_work); @@ -330,6 +353,7 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event) connected: dprintk("RPC: %s: %sconnected\n", __func__, connstate > 0 ? "" : "dis"); + atomic_set(&xprt->rx_buf.rb_credits, 1); ep->rep_connected = connstate; rpcrdma_conn_func(ep); wake_up_all(&ep->rep_connect_wait); @@ -943,6 +967,7 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) buf->rb_max_requests = r_xprt->rx_data.max_requests; buf->rb_bc_srv_max_requests = 0; spin_lock_init(&buf->rb_lock); + atomic_set(&buf->rb_credits, 1); rc = ia->ri_ops->ro_init(r_xprt); if (rc) |