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author | Hariprasad S <hariprasad@chelsio.com> | 2016-05-06 22:18:09 +0530 |
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committer | Doug Ledford <dledford@redhat.com> | 2016-05-13 19:38:10 -0400 |
commit | 093108cb3640844cfdabb0f506fa6b592b64272d (patch) | |
tree | b32dc0e0118d8740a09a90b496c5566ace2bf112 | |
parent | 4a4dd8db9dc15579edc62631326f37c43fda0942 (diff) | |
download | op-kernel-dev-093108cb3640844cfdabb0f506fa6b592b64272d.zip op-kernel-dev-093108cb3640844cfdabb0f506fa6b592b64272d.tar.gz |
RDMA/iw_cxgb4: Always wake up waiter in c4iw_peer_abort_intr()
Currently c4iw_peer_abort_intr() does not wake up the waiter if the
endpoint state indicates we're using MPAv2 and we're currently trying to
connect. This was introduced with commit 7c0a33d61187a ("RDMA/cxgb4:
Don't wakeup threads for MPAv2")
However, this original fix is flawed because it introduces a race that
can cause a deadlock of the iwarp stack. Here is the race:
->local side sets up an active offload connection.
->local side sends MPA_START request.
->peer sends MPA_START response.
->local side ingress cpl thread begins processing the MPA_START response,
but before it changes the state from MPA_REQ_SENT to FPDU_MODE:
->peer sends a RST which results in a ABORT_REQ_RSS. This triggers
peer_abort_intr() which sees the state in MPA_REQ_SENT and since mpa_rev
is 2, it will avoid waking up the endpoint with -ECONNRESET, assuming the
stack will re-attempt the connection using MPAv1.
->Meanwhile, the cpl thread moves the state to FPDU_MODE and calls
c4iw_modify_rc_qp() which calls rdma_init() which sends a RI_WR/INIT WR
to firmware. But since HW sent an abort, FW correctly drops the RI_WR/INIT
WR.
->So the cpl thread is stuck waiting for a reply and cannot process the
ABORT_REQ_RSS cpl sitting in its input queue. Thus everything comes to a
halt because no more ingress cpls are processed by the stack...
The correct fix for the issue is to always do the wake up in
c4iw_abort_intr() but reinitialize the wait object in c4iw_reconnect().
Fixes: 7c0a33d61187a ("RDMA/cxgb4: Don't wakeup threads for MPAv2")
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
-rw-r--r-- | drivers/infiniband/hw/cxgb4/cm.c | 12 |
1 files changed, 2 insertions, 10 deletions
diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c index 0502fac..4f8afa2 100644 --- a/drivers/infiniband/hw/cxgb4/cm.c +++ b/drivers/infiniband/hw/cxgb4/cm.c @@ -2136,6 +2136,7 @@ static int c4iw_reconnect(struct c4iw_ep *ep) PDBG("%s qp %p cm_id %p\n", __func__, ep->com.qp, ep->com.cm_id); init_timer(&ep->timer); + c4iw_init_wr_wait(&ep->com.wr_wait); /* * Allocate an active TID to initiate a TCP connection. @@ -4239,16 +4240,7 @@ static int peer_abort_intr(struct c4iw_dev *dev, struct sk_buff *skb) PDBG("%s ep %p tid %u state %u\n", __func__, ep, ep->hwtid, ep->com.state); - /* - * Wake up any threads in rdma_init() or rdma_fini(). - * However, if we are on MPAv2 and want to retry with MPAv1 - * then, don't wake up yet. - */ - if (mpa_rev == 2 && !ep->tried_with_mpa_v1) { - if (ep->com.state != MPA_REQ_SENT) - c4iw_wake_up(&ep->com.wr_wait, -ECONNRESET); - } else - c4iw_wake_up(&ep->com.wr_wait, -ECONNRESET); + c4iw_wake_up(&ep->com.wr_wait, -ECONNRESET); out: sched(dev, skb); return 0; |