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214 lines
6.5 KiB
214 lines
6.5 KiB
/* |
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* Copyright(c) 2016 Intel Corporation. |
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* |
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* This file is provided under a dual BSD/GPLv2 license. When using or |
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* redistributing this file, you may do so under either license. |
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* |
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* GPL LICENSE SUMMARY |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of version 2 of the GNU General Public License as |
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* published by the Free Software Foundation. |
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* |
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* This program is distributed in the hope that it will be useful, but |
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* WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* General Public License for more details. |
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* |
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* BSD LICENSE |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* - Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* - Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* - Neither the name of Intel Corporation nor the names of its |
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* contributors may be used to endorse or promote products derived |
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* from this software without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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* |
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*/ |
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#include <rdma/rdmavt_qp.h> |
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#include <rdma/ib_hdrs.h> |
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/* |
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* Convert the AETH credit code into the number of credits. |
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*/ |
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static const u16 credit_table[31] = { |
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0, /* 0 */ |
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1, /* 1 */ |
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2, /* 2 */ |
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3, /* 3 */ |
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4, /* 4 */ |
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6, /* 5 */ |
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8, /* 6 */ |
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12, /* 7 */ |
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16, /* 8 */ |
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24, /* 9 */ |
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32, /* A */ |
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48, /* B */ |
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64, /* C */ |
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96, /* D */ |
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128, /* E */ |
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192, /* F */ |
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256, /* 10 */ |
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384, /* 11 */ |
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512, /* 12 */ |
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768, /* 13 */ |
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1024, /* 14 */ |
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1536, /* 15 */ |
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2048, /* 16 */ |
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3072, /* 17 */ |
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4096, /* 18 */ |
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6144, /* 19 */ |
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8192, /* 1A */ |
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12288, /* 1B */ |
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16384, /* 1C */ |
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24576, /* 1D */ |
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32768 /* 1E */ |
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}; |
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/** |
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* rvt_compute_aeth - compute the AETH (syndrome + MSN) |
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* @qp: the queue pair to compute the AETH for |
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* |
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* Returns the AETH. |
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*/ |
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__be32 rvt_compute_aeth(struct rvt_qp *qp) |
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{ |
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u32 aeth = qp->r_msn & IB_MSN_MASK; |
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if (qp->ibqp.srq) { |
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/* |
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* Shared receive queues don't generate credits. |
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* Set the credit field to the invalid value. |
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*/ |
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aeth |= IB_AETH_CREDIT_INVAL << IB_AETH_CREDIT_SHIFT; |
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} else { |
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u32 min, max, x; |
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u32 credits; |
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u32 head; |
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u32 tail; |
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credits = READ_ONCE(qp->r_rq.kwq->count); |
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if (credits == 0) { |
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/* sanity check pointers before trusting them */ |
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if (qp->ip) { |
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head = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->head); |
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tail = RDMA_READ_UAPI_ATOMIC(qp->r_rq.wq->tail); |
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} else { |
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head = READ_ONCE(qp->r_rq.kwq->head); |
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tail = READ_ONCE(qp->r_rq.kwq->tail); |
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} |
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if (head >= qp->r_rq.size) |
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head = 0; |
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if (tail >= qp->r_rq.size) |
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tail = 0; |
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/* |
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* Compute the number of credits available (RWQEs). |
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* There is a small chance that the pair of reads are |
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* not atomic, which is OK, since the fuzziness is |
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* resolved as further ACKs go out. |
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*/ |
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credits = rvt_get_rq_count(&qp->r_rq, head, tail); |
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} |
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/* |
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* Binary search the credit table to find the code to |
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* use. |
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*/ |
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min = 0; |
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max = 31; |
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for (;;) { |
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x = (min + max) / 2; |
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if (credit_table[x] == credits) |
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break; |
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if (credit_table[x] > credits) { |
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max = x; |
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} else { |
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if (min == x) |
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break; |
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min = x; |
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} |
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} |
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aeth |= x << IB_AETH_CREDIT_SHIFT; |
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} |
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return cpu_to_be32(aeth); |
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} |
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EXPORT_SYMBOL(rvt_compute_aeth); |
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/** |
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* rvt_get_credit - flush the send work queue of a QP |
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* @qp: the qp who's send work queue to flush |
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* @aeth: the Acknowledge Extended Transport Header |
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* |
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* The QP s_lock should be held. |
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*/ |
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void rvt_get_credit(struct rvt_qp *qp, u32 aeth) |
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{ |
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struct rvt_dev_info *rdi = ib_to_rvt(qp->ibqp.device); |
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u32 credit = (aeth >> IB_AETH_CREDIT_SHIFT) & IB_AETH_CREDIT_MASK; |
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lockdep_assert_held(&qp->s_lock); |
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/* |
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* If the credit is invalid, we can send |
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* as many packets as we like. Otherwise, we have to |
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* honor the credit field. |
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*/ |
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if (credit == IB_AETH_CREDIT_INVAL) { |
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if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) { |
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qp->s_flags |= RVT_S_UNLIMITED_CREDIT; |
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if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) { |
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qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT; |
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rdi->driver_f.schedule_send(qp); |
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} |
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} |
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} else if (!(qp->s_flags & RVT_S_UNLIMITED_CREDIT)) { |
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/* Compute new LSN (i.e., MSN + credit) */ |
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credit = (aeth + credit_table[credit]) & IB_MSN_MASK; |
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if (rvt_cmp_msn(credit, qp->s_lsn) > 0) { |
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qp->s_lsn = credit; |
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if (qp->s_flags & RVT_S_WAIT_SSN_CREDIT) { |
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qp->s_flags &= ~RVT_S_WAIT_SSN_CREDIT; |
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rdi->driver_f.schedule_send(qp); |
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} |
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} |
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} |
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} |
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EXPORT_SYMBOL(rvt_get_credit); |
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/** |
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* rvt_restart_sge - rewind the sge state for a wqe |
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* @ss: the sge state pointer |
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* @wqe: the wqe to rewind |
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* @len: the data length from the start of the wqe in bytes |
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* |
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* Returns the remaining data length. |
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*/ |
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u32 rvt_restart_sge(struct rvt_sge_state *ss, struct rvt_swqe *wqe, u32 len) |
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{ |
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ss->sge = wqe->sg_list[0]; |
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ss->sg_list = wqe->sg_list + 1; |
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ss->num_sge = wqe->wr.num_sge; |
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ss->total_len = wqe->length; |
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rvt_skip_sge(ss, len, false); |
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return wqe->length - len; |
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} |
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EXPORT_SYMBOL(rvt_restart_sge); |
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