diff options
| author | Ralph Campbell <ralph.campbell@qlogic.com> | 2007-05-03 12:43:03 -0700 |
|---|---|---|
| committer | Roland Dreier <rolandd@cisco.com> | 2007-05-06 21:18:11 -0700 |
| commit | 154257f3626ea6dd96781fac0896c3f27fe2b0a1 (patch) | |
| tree | ab91781594c064b9b7af781f8271000298ddf32b /drivers/infiniband/hw | |
| parent | 6ed89b9574776d4178f1ad754d20e4f1e5a4b6c8 (diff) | |
| download | talos-obmc-linux-154257f3626ea6dd96781fac0896c3f27fe2b0a1.tar.gz talos-obmc-linux-154257f3626ea6dd96781fac0896c3f27fe2b0a1.zip | |
IB/ipath: Fix a race condition when generating ACKs
Fix a problem where simple ACKs can be sent ahead of RDMA read
responses thus implicitly NAKing the RDMA read.
Signed-off-by: Ralph Campbell <ralph.cambpell@qlogic.com>
Signed-off-by: Robert Walsh <robert.walsh@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/infiniband/hw')
| -rw-r--r-- | drivers/infiniband/hw/ipath/ipath_rc.c | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_rc.c b/drivers/infiniband/hw/ipath/ipath_rc.c index f4d729d5dd1a..1915771fd038 100644 --- a/drivers/infiniband/hw/ipath/ipath_rc.c +++ b/drivers/infiniband/hw/ipath/ipath_rc.c @@ -98,13 +98,21 @@ static int ipath_make_rc_ack(struct ipath_qp *qp, case OP(RDMA_READ_RESPONSE_LAST): case OP(RDMA_READ_RESPONSE_ONLY): case OP(ATOMIC_ACKNOWLEDGE): - qp->s_ack_state = OP(ACKNOWLEDGE); + /* + * We can increment the tail pointer now that the last + * response has been sent instead of only being + * constructed. + */ + if (++qp->s_tail_ack_queue > IPATH_MAX_RDMA_ATOMIC) + qp->s_tail_ack_queue = 0; /* FALLTHROUGH */ + case OP(SEND_ONLY): case OP(ACKNOWLEDGE): /* Check for no next entry in the queue. */ if (qp->r_head_ack_queue == qp->s_tail_ack_queue) { if (qp->s_flags & IPATH_S_ACK_PENDING) goto normal; + qp->s_ack_state = OP(ACKNOWLEDGE); goto bail; } @@ -117,12 +125,8 @@ static int ipath_make_rc_ack(struct ipath_qp *qp, if (len > pmtu) { len = pmtu; qp->s_ack_state = OP(RDMA_READ_RESPONSE_FIRST); - } else { + } else qp->s_ack_state = OP(RDMA_READ_RESPONSE_ONLY); - if (++qp->s_tail_ack_queue > - IPATH_MAX_RDMA_ATOMIC) - qp->s_tail_ack_queue = 0; - } ohdr->u.aeth = ipath_compute_aeth(qp); hwords++; qp->s_ack_rdma_psn = e->psn; @@ -139,8 +143,6 @@ static int ipath_make_rc_ack(struct ipath_qp *qp, cpu_to_be32(e->atomic_data); hwords += sizeof(ohdr->u.at) / sizeof(u32); bth2 = e->psn; - if (++qp->s_tail_ack_queue > IPATH_MAX_RDMA_ATOMIC) - qp->s_tail_ack_queue = 0; } bth0 = qp->s_ack_state << 24; break; @@ -156,8 +158,6 @@ static int ipath_make_rc_ack(struct ipath_qp *qp, ohdr->u.aeth = ipath_compute_aeth(qp); hwords++; qp->s_ack_state = OP(RDMA_READ_RESPONSE_LAST); - if (++qp->s_tail_ack_queue > IPATH_MAX_RDMA_ATOMIC) - qp->s_tail_ack_queue = 0; } bth0 = qp->s_ack_state << 24; bth2 = qp->s_ack_rdma_psn++ & IPATH_PSN_MASK; @@ -171,7 +171,7 @@ static int ipath_make_rc_ack(struct ipath_qp *qp, * the ACK before setting s_ack_state to ACKNOWLEDGE * (see above). */ - qp->s_ack_state = OP(ATOMIC_ACKNOWLEDGE); + qp->s_ack_state = OP(SEND_ONLY); qp->s_flags &= ~IPATH_S_ACK_PENDING; qp->s_cur_sge = NULL; if (qp->s_nak_state) @@ -223,7 +223,7 @@ int ipath_make_rc_req(struct ipath_qp *qp, /* Sending responses has higher priority over sending requests. */ if ((qp->r_head_ack_queue != qp->s_tail_ack_queue || (qp->s_flags & IPATH_S_ACK_PENDING) || - qp->s_ack_state != IB_OPCODE_RC_ACKNOWLEDGE) && + qp->s_ack_state != OP(ACKNOWLEDGE)) && ipath_make_rc_ack(qp, ohdr, pmtu, bth0p, bth2p)) goto done; @@ -585,7 +585,9 @@ static void send_rc_ack(struct ipath_qp *qp) unsigned long flags; /* Don't send ACK or NAK if a RDMA read or atomic is pending. */ - if (qp->r_head_ack_queue != qp->s_tail_ack_queue) + if (qp->r_head_ack_queue != qp->s_tail_ack_queue || + (qp->s_flags & IPATH_S_ACK_PENDING) || + qp->s_ack_state != OP(ACKNOWLEDGE)) goto queue_ack; /* Construct the header. */ |
