diff options
| author | Tom Tucker <tom@opengridcomputing.com> | 2008-08-13 11:05:41 -0500 |
|---|---|---|
| committer | J. Bruce Fields <bfields@citi.umich.edu> | 2008-08-13 16:57:31 -0400 |
| commit | 24b8b44780a2c53ecb738f4a1c08d114f5eda27c (patch) | |
| tree | f772e59438783c6230158ea65bd5aeb3f84f4202 /net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | |
| parent | 30a2f3c60a84092c8084dfe788b710f8d0768cd4 (diff) | |
| download | linux-24b8b44780a2c53ecb738f4a1c08d114f5eda27c.tar.gz | |
svcrdma: Fix race between svc_rdma_recvfrom thread and the dto_tasklet
RDMA_READ completions are kept on a separate queue from the general I/O request queue. Since a separate lock is used to protect the RDMA_READ completion queue, a race exists between the dto_tasklet and the svc_rdma_recvfrom thread where the dto_tasklet sets the XPT_DATA bit and adds I/O to the read-completion queue. Concurrently, the recvfrom thread checks the generic queue, finds it empty and resets the XPT_DATA bit. A subsequent svc_xprt_enqueue will fail to enqueue the transport for I/O and cause the transport to "stall". The fix is to protect both lists with the same lock and set the XPT_DATA bit with this lock held. Signed-off-by: Tom Tucker <tom@opengridcomputing.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Diffstat (limited to 'net/sunrpc/xprtrdma/svc_rdma_recvfrom.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index b4b17f44cb29..74de31a06616 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -443,18 +443,18 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) dprintk("svcrdma: rqstp=%p\n", rqstp); - spin_lock_bh(&rdma_xprt->sc_read_complete_lock); + spin_lock_bh(&rdma_xprt->sc_rq_dto_lock); if (!list_empty(&rdma_xprt->sc_read_complete_q)) { ctxt = list_entry(rdma_xprt->sc_read_complete_q.next, struct svc_rdma_op_ctxt, dto_q); list_del_init(&ctxt->dto_q); } - spin_unlock_bh(&rdma_xprt->sc_read_complete_lock); - if (ctxt) + if (ctxt) { + spin_unlock_bh(&rdma_xprt->sc_rq_dto_lock); return rdma_read_complete(rqstp, ctxt); + } - spin_lock_bh(&rdma_xprt->sc_rq_dto_lock); if (!list_empty(&rdma_xprt->sc_rq_dto_q)) { ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next, struct svc_rdma_op_ctxt, |