From 65d8013cbdc661f9cb7645148de1facfe3d0c88a Mon Sep 17 00:00:00 2001
From: Stefan Raspl <raspl@linux.vnet.ibm.com>
Date: Sun, 7 Apr 2013 22:19:27 +0000
Subject: [PATCH] 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 <raspl@linux.vnet.ibm.com>
Signed-off-by: Frank Blaschka <blaschka@linux.vnet.ibm.com>
Reviewed-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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 8c0622399fcd6..6ccb7457746b2 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 0d73a999983d9..451f92020599e 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 d690166efeaff..155b101bd7309 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 8710337dab3ec..1f7edf1b26c33 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;
--
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