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RDMA/rxe: Remove __rxe_do_task()

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The subroutine __rxe_do_task is not thread safe and it has no way to
guarantee that the tasks, which are designed with the assumption that they
are non-reentrant, are not reentered. All of its uses are non-performance
critical.

This patch replaces calls to __rxe_do_task with calls to
rxe_sched_task. It also removes irrelevant or unneeded if tests.

Instead of calling the task machinery a single call to the tasklet
function (rxe_requester, etc.) is sufficient to draing the queues if task
execution has been disabled or stopped.

Together these changes allow the removal of __rxe_do_task.

Link: https://lore.kernel.org/r/20230304174533.11296-7-rpearsonhpe@gmail.com
Signed-off-by: Ian Ziemba <ian.ziemba@hpe.com>
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Bob Pearson
2023-03-04 11:45:32 -06:00
committed by Jason Gunthorpe
parent a246aa2e8a
commit 960ebe97e5
3 changed files with 17 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

56
drivers/infiniband/sw/rxe/rxe_qp.c
View File

@@ -473,29 +473,23 @@ static void rxe_qp_reset(struct rxe_qp *qp)
{
/* stop tasks from running */
rxe_disable_task(&qp->resp.task);
/* stop request/comp */
if (qp->sq.queue) {
if (qp_type(qp) == IB_QPT_RC)
rxe_disable_task(&qp->comp.task);
rxe_disable_task(&qp->req.task);
}
rxe_disable_task(&qp->comp.task);
rxe_disable_task(&qp->req.task);
/* move qp to the reset state */
qp->req.state = QP_STATE_RESET;
qp->comp.state = QP_STATE_RESET;
qp->resp.state = QP_STATE_RESET;
/* let state machines reset themselves drain work and packet queues
* etc.
*/
__rxe_do_task(&qp->resp.task);
/* drain work and packet queuesc */
rxe_requester(qp);
rxe_completer(qp);
rxe_responder(qp);
if (qp->sq.queue) {
__rxe_do_task(&qp->comp.task);
__rxe_do_task(&qp->req.task);
if (qp->rq.queue)
rxe_queue_reset(qp->rq.queue);
if (qp->sq.queue)
rxe_queue_reset(qp->sq.queue);
}
/* cleanup attributes */
atomic_set(&qp->ssn, 0);
@@ -518,13 +512,8 @@ static void rxe_qp_reset(struct rxe_qp *qp)
/* reenable tasks */
rxe_enable_task(&qp->resp.task);
if (qp->sq.queue) {
if (qp_type(qp) == IB_QPT_RC)
rxe_enable_task(&qp->comp.task);
rxe_enable_task(&qp->req.task);
}
rxe_enable_task(&qp->comp.task);
rxe_enable_task(&qp->req.task);
}
/* drain the send queue */
@@ -533,10 +522,7 @@ static void rxe_qp_drain(struct rxe_qp *qp)
if (qp->sq.queue) {
if (qp->req.state != QP_STATE_DRAINED) {
qp->req.state = QP_STATE_DRAIN;
if (qp_type(qp) == IB_QPT_RC)
rxe_sched_task(&qp->comp.task);
else
__rxe_do_task(&qp->comp.task);
rxe_sched_task(&qp->comp.task);
rxe_sched_task(&qp->req.task);
}
}
@@ -552,11 +538,7 @@ void rxe_qp_error(struct rxe_qp *qp)
/* drain work and packet queues */
rxe_sched_task(&qp->resp.task);
if (qp_type(qp) == IB_QPT_RC)
rxe_sched_task(&qp->comp.task);
else
__rxe_do_task(&qp->comp.task);
rxe_sched_task(&qp->comp.task);
rxe_sched_task(&qp->req.task);
}
@@ -773,24 +755,20 @@ static void rxe_qp_do_cleanup(struct work_struct *work)
qp->valid = 0;
qp->qp_timeout_jiffies = 0;
rxe_cleanup_task(&qp->resp.task);
if (qp_type(qp) == IB_QPT_RC) {
del_timer_sync(&qp->retrans_timer);
del_timer_sync(&qp->rnr_nak_timer);
}
rxe_cleanup_task(&qp->resp.task);
rxe_cleanup_task(&qp->req.task);
rxe_cleanup_task(&qp->comp.task);
/* flush out any receive wr's or pending requests */
if (qp->req.task.func)
__rxe_do_task(&qp->req.task);
if (qp->sq.queue) {
__rxe_do_task(&qp->comp.task);
__rxe_do_task(&qp->req.task);
}
rxe_requester(qp);
rxe_completer(qp);
rxe_responder(qp);
if (qp->sq.queue)
rxe_queue_cleanup(qp->sq.queue);

13
drivers/infiniband/sw/rxe/rxe_task.c
View File

@@ -6,19 +6,6 @@
#include "rxe.h"
int __rxe_do_task(struct rxe_task *task)
{
int ret;
while ((ret = task->func(task->qp)) == 0)
;
task->ret = ret;
return ret;
}
/*
* this locking is due to a potential race where
* a second caller finds the task already running

6
drivers/infiniband/sw/rxe/rxe_task.h
View File

@@ -39,12 +39,6 @@ int rxe_init_task(struct rxe_task *task, struct rxe_qp *qp,
/* cleanup task */
void rxe_cleanup_task(struct rxe_task *task);
/*
* raw call to func in loop without any checking
* can call when tasklets are disabled
*/
int __rxe_do_task(struct rxe_task *task);
void rxe_run_task(struct rxe_task *task);
void rxe_sched_task(struct rxe_task *task);