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Commit a6018888 authored by Karthikeyan Ramasubramanian's avatar Karthikeyan Ramasubramanian Committed by Gerrit - the friendly Code Review server
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soc: qcom: glink_smd_xprt: Defer channel close ACK operation 



Depending on the timing of two competing transport registration with
G-Link core, a channel gets opened on one transport and then immediately
migrated to another transport. This channel migration happens in the
context of glink_open() operation itself and causes a re-lock attempt
on an already locked mutex.

Defer the channel close ACK operation so that channel migration does not
hit the deadlock.

CRs-Fixed: 1004150
Change-Id: I188846b95369b674830bc01ddeca764ad6d4d391
Signed-off-by: default avatarKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
parent e80f64ee

drivers/soc/qcom/glink_smd_xprt.c

+25 −5
Original line number Diff line number Diff line
@@ -561,6 +561,24 @@ static void ssr_work_func(struct work_struct *work) 
	mutex_unlock(&einfo->in_ssr_lock);

}



/**

 * deferred_close_ack() - Generate a deferred channel close ack

 * @work:	The channel close ack work to generate.

 */

static void deferred_close_ack(struct work_struct *work)

{

	struct channel_work *ch_work;

	struct channel *ch;



	ch_work = container_of(work, struct channel_work, work);

	ch = ch_work->ch;

	mutex_lock(&ch->edge->rx_cmd_lock);

	ch->edge->xprt_if.glink_core_if_ptr->rx_cmd_ch_close_ack(

				&ch->edge->xprt_if, ch->lcid);

	mutex_unlock(&ch->edge->rx_cmd_lock);

	kfree(ch_work);

}



/**

 * process_tx_done() - process a tx done task

 * @work:	The tx done task to process.
@@ -904,6 +922,7 @@ static void smd_data_ch_close(struct channel *ch) 
{

	struct intent_info *intent;

	unsigned long flags;

	struct channel_work *ch_work;



	SMDXPRT_INFO(ch->edge, "%s Closing SMD channel lcid %u\n",

			__func__, ch->lcid);
@@ -924,11 +943,12 @@ static void smd_data_ch_close(struct channel *ch) 
		smd_close(ch->smd_ch);

		ch->smd_ch = NULL;

	} else if (ch->local_legacy) {

		mutex_lock(&ch->edge->rx_cmd_lock);

		ch->edge->xprt_if.glink_core_if_ptr->rx_cmd_ch_close_ack(

							&ch->edge->xprt_if,

							ch->lcid);

		mutex_unlock(&ch->edge->rx_cmd_lock);

		ch_work = kzalloc(sizeof(*ch_work), GFP_KERNEL);

		if (ch_work) {

			ch_work->ch = ch;

			INIT_WORK(&ch_work->work, deferred_close_ack);

			queue_work(ch->wq, &ch_work->work);

		}

	}

	mutex_unlock(&ch->ch_probe_lock);