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Commit 65d8013c authored by Stefan Raspl's avatar Stefan Raspl Committed by David S. Miller
Browse files

qeth: fix qeth_wait_for_threads() deadlock for OSN devices 



Any recovery thread will deadlock when calling qeth_wait_for_threads(), most
notably when triggering a recovery on an OSN device.
This patch will store the recovery thread's task pointer on recovery
invocation and check in qeth_wait_for_threads() respectively to avoid
deadlocks.

Signed-off-by: default avatarStefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: default avatarFrank Blaschka <blaschka@linux.vnet.ibm.com>
Reviewed-by: default avatarUrsula Braun <ursula.braun@de.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f9c41a62

drivers/s390/net/qeth_core.h

+3 −0
Original line number Diff line number Diff line
@@ -769,6 +769,7 @@ struct qeth_card { 
	unsigned long thread_start_mask;

	unsigned long thread_allowed_mask;

	unsigned long thread_running_mask;

	struct task_struct *recovery_task;

	spinlock_t ip_lock;

	struct list_head ip_list;

	struct list_head *ip_tbd_list;
@@ -862,6 +863,8 @@ extern struct qeth_card_list_struct qeth_core_card_list; 
extern struct kmem_cache *qeth_core_header_cache;

extern struct qeth_dbf_info qeth_dbf[QETH_DBF_INFOS];



void qeth_set_recovery_task(struct qeth_card *);

void qeth_clear_recovery_task(struct qeth_card *);

void qeth_set_allowed_threads(struct qeth_card *, unsigned long , int);

int qeth_threads_running(struct qeth_card *, unsigned long);

int qeth_wait_for_threads(struct qeth_card *, unsigned long);

drivers/s390/net/qeth_core_main.c

+19 −0
Original line number Diff line number Diff line
@@ -177,6 +177,23 @@ const char *qeth_get_cardname_short(struct qeth_card *card) 
	return "n/a";

}



void qeth_set_recovery_task(struct qeth_card *card)

{

	card->recovery_task = current;

}

EXPORT_SYMBOL_GPL(qeth_set_recovery_task);



void qeth_clear_recovery_task(struct qeth_card *card)

{

	card->recovery_task = NULL;

}

EXPORT_SYMBOL_GPL(qeth_clear_recovery_task);



static bool qeth_is_recovery_task(const struct qeth_card *card)

{

	return card->recovery_task == current;

}



void qeth_set_allowed_threads(struct qeth_card *card, unsigned long threads,

			 int clear_start_mask)

{
@@ -205,6 +222,8 @@ EXPORT_SYMBOL_GPL(qeth_threads_running); 


int qeth_wait_for_threads(struct qeth_card *card, unsigned long threads)

{

	if (qeth_is_recovery_task(card))

		return 0;

	return wait_event_interruptible(card->wait_q,

			qeth_threads_running(card, threads) == 0);

}

drivers/s390/net/qeth_l2_main.c

+2 −0
Original line number Diff line number Diff line
@@ -1143,6 +1143,7 @@ static int qeth_l2_recover(void *ptr) 
	QETH_CARD_TEXT(card, 2, "recover2");

	dev_warn(&card->gdev->dev,

		"A recovery process has been started for the device\n");

	qeth_set_recovery_task(card);

	__qeth_l2_set_offline(card->gdev, 1);

	rc = __qeth_l2_set_online(card->gdev, 1);

	if (!rc)
@@ -1153,6 +1154,7 @@ static int qeth_l2_recover(void *ptr) 
		dev_warn(&card->gdev->dev, "The qeth device driver "

				"failed to recover an error on the device\n");

	}

	qeth_clear_recovery_task(card);

	qeth_clear_thread_start_bit(card, QETH_RECOVER_THREAD);

	qeth_clear_thread_running_bit(card, QETH_RECOVER_THREAD);

	return 0;

drivers/s390/net/qeth_l3_main.c

+2 −0
Original line number Diff line number Diff line
@@ -3515,6 +3515,7 @@ static int qeth_l3_recover(void *ptr) 
	QETH_CARD_TEXT(card, 2, "recover2");

	dev_warn(&card->gdev->dev,

		"A recovery process has been started for the device\n");

	qeth_set_recovery_task(card);

	__qeth_l3_set_offline(card->gdev, 1);

	rc = __qeth_l3_set_online(card->gdev, 1);

	if (!rc)
@@ -3525,6 +3526,7 @@ static int qeth_l3_recover(void *ptr) 
		dev_warn(&card->gdev->dev, "The qeth device driver "

				"failed to recover an error on the device\n");

	}

	qeth_clear_recovery_task(card);

	qeth_clear_thread_start_bit(card, QETH_RECOVER_THREAD);

	qeth_clear_thread_running_bit(card, QETH_RECOVER_THREAD);

	return 0;