From 65d8013cbdc661f9cb7645148de1facfe3d0c88a Mon Sep 17 00:00:00 2001 From: Stefan Raspl Date: Sun, 7 Apr 2013 22:19:27 +0000 Subject: 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: Stefan Raspl Signed-off-by: Frank Blaschka Reviewed-by: Ursula Braun Signed-off-by: David S. Miller --- drivers/s390/net/qeth_core.h | 3 +++ drivers/s390/net/qeth_core_main.c | 19 +++++++++++++++++++ drivers/s390/net/qeth_l2_main.c | 2 ++ drivers/s390/net/qeth_l3_main.c | 2 ++ 4 files changed, 26 insertions(+) diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h index 8c0622399fcd..6ccb7457746b 100644 --- a/drivers/s390/net/qeth_core.h +++ b/drivers/s390/net/qeth_core.h @@ -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); diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 0d73a999983d..451f92020599 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -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); } diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index d690166efeaf..155b101bd730 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -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; diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index 8710337dab3e..1f7edf1b26c3 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -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; -- cgit v1.2.3