Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8628991f authored by Bart Van Assche's avatar Bart Van Assche Committed by Doug Ledford
Browse files

IB/srpt: Use a mutex to protect the channel list 



In a later patch a function that can block will be called while
iterating over the rch_list. Hence protect that list with a
mutex instead of a spinlock. And since it is not allowed to sleep
while the task state != TASK_RUNNING, convert the list test in
srpt_ch_list_empty() into a lockless test.

Signed-off-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Alex Estrin <alex.estrin@intel.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent c13c90ea

drivers/infiniband/ulp/srpt/ib_srpt.c

+15 −27
Original line number Diff line number Diff line
@@ -1862,12 +1862,11 @@ static void __srpt_close_ch(struct srpt_rdma_ch *ch) 
 */

static void srpt_close_ch(struct srpt_rdma_ch *ch)

{

	struct srpt_device *sdev;

	struct srpt_device *sdev = ch->sport->sdev;



	sdev = ch->sport->sdev;

	spin_lock_irq(&sdev->spinlock);

	mutex_lock(&sdev->mutex);

	__srpt_close_ch(ch);

	spin_unlock_irq(&sdev->spinlock);

	mutex_unlock(&sdev->mutex);

}



/**
@@ -1954,11 +1953,11 @@ static void srpt_release_channel_work(struct work_struct *w) 
			     ch->sport->sdev, ch->rq_size,

			     ch->rsp_size, DMA_TO_DEVICE);



	spin_lock_irq(&sdev->spinlock);

	mutex_lock(&sdev->mutex);

	list_del_init(&ch->list);

	if (ch->release_done)

		complete(ch->release_done);

	spin_unlock_irq(&sdev->spinlock);

	mutex_unlock(&sdev->mutex);



	wake_up(&sdev->ch_releaseQ);
@@ -2039,7 +2038,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id, 
	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {

		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;



		spin_lock_irq(&sdev->spinlock);

		mutex_lock(&sdev->mutex);



		list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) {

			if (!memcmp(ch->i_port_id, req->initiator_port_id, 16)
@@ -2063,7 +2062,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id, 
			}

		}



		spin_unlock_irq(&sdev->spinlock);

		mutex_unlock(&sdev->mutex);



	} else

		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
@@ -2208,9 +2207,9 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id, 
		goto release_channel;

	}



	spin_lock_irq(&sdev->spinlock);

	mutex_lock(&sdev->mutex);

	list_add_tail(&ch->list, &sdev->rch_list);

	spin_unlock_irq(&sdev->spinlock);

	mutex_unlock(&sdev->mutex);



	goto out;
@@ -2653,17 +2652,6 @@ static void srpt_refresh_port_work(struct work_struct *work) 
	srpt_refresh_port(sport);

}



static int srpt_ch_list_empty(struct srpt_device *sdev)

{

	int res;



	spin_lock_irq(&sdev->spinlock);

	res = list_empty(&sdev->rch_list);

	spin_unlock_irq(&sdev->spinlock);



	return res;

}



/**

 * srpt_release_sdev() - Free the channel resources associated with a target.

 */
@@ -2676,13 +2664,13 @@ static int srpt_release_sdev(struct srpt_device *sdev) 


	BUG_ON(!sdev);



	spin_lock_irq(&sdev->spinlock);

	mutex_lock(&sdev->mutex);

	list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list)

		__srpt_close_ch(ch);

	spin_unlock_irq(&sdev->spinlock);

	mutex_unlock(&sdev->mutex);



	res = wait_event_interruptible(sdev->ch_releaseQ,

				       srpt_ch_list_empty(sdev));

				       list_empty_careful(&sdev->rch_list));

	if (res)

		pr_err("%s: interrupted.\n", __func__);
@@ -2743,7 +2731,7 @@ static void srpt_add_one(struct ib_device *device) 
	sdev->device = device;

	INIT_LIST_HEAD(&sdev->rch_list);

	init_waitqueue_head(&sdev->ch_releaseQ);

	spin_lock_init(&sdev->spinlock);

	mutex_init(&sdev->mutex);



	sdev->pd = ib_alloc_pd(device);

	if (IS_ERR(sdev->pd))
@@ -2971,12 +2959,12 @@ static void srpt_close_session(struct se_session *se_sess) 
	pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,

		 ch->state);



	spin_lock_irq(&sdev->spinlock);

	mutex_lock(&sdev->mutex);

	BUG_ON(ch->release_done);

	ch->release_done = &release_done;

	wait = !list_empty(&ch->list);

	__srpt_close_ch(ch);

	spin_unlock_irq(&sdev->spinlock);

	mutex_unlock(&sdev->mutex);



	if (!wait)

		return;

drivers/infiniband/ulp/srpt/ib_srpt.h

+2 −2
Original line number Diff line number Diff line
@@ -342,7 +342,7 @@ struct srpt_port { 
 * @ioctx_ring:    Per-HCA SRQ.

 * @rch_list:      Per-device channel list -- see also srpt_rdma_ch.list.

 * @ch_releaseQ:   Enables waiting for removal from rch_list.

 * @spinlock:      Protects rch_list and tpg.

 * @mutex:         Protects rch_list.

 * @port:          Information about the ports owned by this HCA.

 * @event_handler: Per-HCA asynchronous IB event handler.

 * @list:          Node in srpt_dev_list.
@@ -356,7 +356,7 @@ struct srpt_device { 
	struct srpt_recv_ioctx	**ioctx_ring;

	struct list_head	rch_list;

	wait_queue_head_t	ch_releaseQ;

	spinlock_t		spinlock;

	struct mutex		mutex;

	struct srpt_port	port[2];

	struct ib_event_handler	event_handler;

	struct list_head	list;