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IB/hfi1: Prevent kernel QP post send hard lockups

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The driver progress routines can call cond_resched() when
a timeslice is exhausted and irqs are enabled.

If the ULP had been holding a spin lock without disabling irqs and
the post send directly called the progress routine, the cond_resched()
could yield allowing another thread from the same ULP to deadlock
on that same lock.

Correct by replacing the current hfi1_do_send() calldown with a unique
one for post send and adding an argument to hfi1_do_send() to indicate
that the send engine is running in a thread.   If the routine is not
running in a thread, avoid calling cond_resched().

CC: <stable@vger.kernel.org> # 4.7.x-
Fixes: Commit 831464ce4b ("IB/hfi1: Don't call cond_resched in atomic mode when sending packets")
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Mike Marciniszyn 2017-04-09 10:16:35 -07:00 committed by Doug Ledford
parent 3d591099a0
commit b6eac931b9
3 changed files with 22 additions and 14 deletions
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26
drivers/infiniband/hw/hfi1/ruc.c
View File

@ -1,5 +1,5 @@
/*
* Copyright(c) 2015, 2016 Intel Corporation.
* Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
@ -784,23 +784,29 @@ void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
/* when sending, force a reschedule every one of these periods */
#define SEND_RESCHED_TIMEOUT (5 * HZ) /* 5s in jiffies */
void hfi1_do_send_from_rvt(struct rvt_qp *qp)
{
hfi1_do_send(qp, false);
}
void _hfi1_do_send(struct work_struct *work)
{
struct iowait *wait = container_of(work, struct iowait, iowork);
struct rvt_qp *qp = iowait_to_qp(wait);
hfi1_do_send(qp);
hfi1_do_send(qp, true);
}
/**
* hfi1_do_send - perform a send on a QP
* @work: contains a pointer to the QP
* @in_thread: true if in a workqueue thread
*
* Process entries in the send work queue until credit or queue is
* exhausted. Only allow one CPU to send a packet per QP.
* Otherwise, two threads could send packets out of order.
*/
void hfi1_do_send(struct rvt_qp *qp)
void hfi1_do_send(struct rvt_qp *qp, bool in_thread)
{
struct hfi1_pkt_state ps;
struct hfi1_qp_priv *priv = qp->priv;
@ -868,8 +874,10 @@ void hfi1_do_send(struct rvt_qp *qp)
qp->s_hdrwords = 0;
/* allow other tasks to run */
if (unlikely(time_after(jiffies, timeout))) {
if (workqueue_congested(cpu,
ps.ppd->hfi1_wq)) {
if (!in_thread ||
workqueue_congested(
cpu,
ps.ppd->hfi1_wq)) {
spin_lock_irqsave(
&qp->s_lock,
ps.flags);
@ -882,11 +890,9 @@ void hfi1_do_send(struct rvt_qp *qp)
*ps.ppd->dd->send_schedule);
return;
}
if (!irqs_disabled()) {
cond_resched();
this_cpu_inc(
*ps.ppd->dd->send_schedule);
}
cond_resched();
this_cpu_inc(
*ps.ppd->dd->send_schedule);
timeout = jiffies + (timeout_int) / 8;
}
spin_lock_irqsave(&qp->s_lock, ps.flags);

4
drivers/infiniband/hw/hfi1/verbs.c
View File

@ -1,5 +1,5 @@
/*
* Copyright(c) 2015, 2016 Intel Corporation.
* Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
@ -1820,7 +1820,7 @@ int hfi1_register_ib_device(struct hfi1_devdata *dd)
dd->verbs_dev.rdi.driver_f.qp_priv_free = qp_priv_free;
dd->verbs_dev.rdi.driver_f.free_all_qps = free_all_qps;
dd->verbs_dev.rdi.driver_f.notify_qp_reset = notify_qp_reset;
dd->verbs_dev.rdi.driver_f.do_send = hfi1_do_send;
dd->verbs_dev.rdi.driver_f.do_send = hfi1_do_send_from_rvt;
dd->verbs_dev.rdi.driver_f.schedule_send = hfi1_schedule_send;
dd->verbs_dev.rdi.driver_f.schedule_send_no_lock = _hfi1_schedule_send;
dd->verbs_dev.rdi.driver_f.get_pmtu_from_attr = get_pmtu_from_attr;

6
drivers/infiniband/hw/hfi1/verbs.h
View File

@ -1,5 +1,5 @@
/*
* Copyright(c) 2015, 2016 Intel Corporation.
* Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
@ -355,7 +355,9 @@ void hfi1_make_ruc_header(struct rvt_qp *qp, struct ib_other_headers *ohdr,
void _hfi1_do_send(struct work_struct *work);
void hfi1_do_send(struct rvt_qp *qp);
void hfi1_do_send_from_rvt(struct rvt_qp *qp);
void hfi1_do_send(struct rvt_qp *qp, bool in_thread);
void hfi1_send_complete(struct rvt_qp *qp, struct rvt_swqe *wqe,
enum ib_wc_status status);