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path: root/drivers/s390/crypto/ap_bus.c
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Diffstat (limited to 'drivers/s390/crypto/ap_bus.c')
-rw-r--r--drivers/s390/crypto/ap_bus.c59
1 files changed, 37 insertions, 22 deletions
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index f9f682f19415..60cea6c24349 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -107,6 +107,7 @@ debug_info_t *ap_dbf_info;
static bool ap_scan_bus(void);
static bool ap_scan_bus_result; /* result of last ap_scan_bus() */
static DEFINE_MUTEX(ap_scan_bus_mutex); /* mutex ap_scan_bus() invocations */
+static struct task_struct *ap_scan_bus_task; /* thread holding the scan mutex */
static atomic64_t ap_scan_bus_count; /* counter ap_scan_bus() invocations */
static int ap_scan_bus_time = AP_CONFIG_TIME;
static struct timer_list ap_scan_bus_timer;
@@ -733,7 +734,7 @@ static void ap_check_bindings_complete(void)
if (!completion_done(&ap_apqn_bindings_complete)) {
complete_all(&ap_apqn_bindings_complete);
ap_send_bindings_complete_uevent();
- pr_debug("%s all apqn bindings complete\n", __func__);
+ pr_debug("all apqn bindings complete\n");
}
}
}
@@ -768,7 +769,7 @@ int ap_wait_apqn_bindings_complete(unsigned long timeout)
else if (l == 0 && timeout)
rc = -ETIME;
- pr_debug("%s rc=%d\n", __func__, rc);
+ pr_debug("rc=%d\n", rc);
return rc;
}
EXPORT_SYMBOL(ap_wait_apqn_bindings_complete);
@@ -795,8 +796,7 @@ static int __ap_revise_reserved(struct device *dev, void *dummy)
drvres = to_ap_drv(dev->driver)->flags
& AP_DRIVER_FLAG_DEFAULT;
if (!!devres != !!drvres) {
- pr_debug("%s reprobing queue=%02x.%04x\n",
- __func__, card, queue);
+ pr_debug("reprobing queue=%02x.%04x\n", card, queue);
rc = device_reprobe(dev);
if (rc)
AP_DBF_WARN("%s reprobing queue=%02x.%04x failed\n",
@@ -1000,17 +1000,31 @@ bool ap_bus_force_rescan(void)
unsigned long scan_counter = atomic64_read(&ap_scan_bus_count);
bool rc = false;
- pr_debug(">%s scan counter=%lu\n", __func__, scan_counter);
+ pr_debug("> scan counter=%lu\n", scan_counter);
/* Only trigger AP bus scans after the initial scan is done */
if (scan_counter <= 0)
goto out;
+ /*
+ * There is one unlikely but nevertheless valid scenario where the
+ * thread holding the mutex may try to send some crypto load but
+ * all cards are offline so a rescan is triggered which causes
+ * a recursive call of ap_bus_force_rescan(). A simple return if
+ * the mutex is already locked by this thread solves this.
+ */
+ if (mutex_is_locked(&ap_scan_bus_mutex)) {
+ if (ap_scan_bus_task == current)
+ goto out;
+ }
+
/* Try to acquire the AP scan bus mutex */
if (mutex_trylock(&ap_scan_bus_mutex)) {
/* mutex acquired, run the AP bus scan */
+ ap_scan_bus_task = current;
ap_scan_bus_result = ap_scan_bus();
rc = ap_scan_bus_result;
+ ap_scan_bus_task = NULL;
mutex_unlock(&ap_scan_bus_mutex);
goto out;
}
@@ -1029,7 +1043,7 @@ bool ap_bus_force_rescan(void)
mutex_unlock(&ap_scan_bus_mutex);
out:
- pr_debug("%s rc=%d\n", __func__, rc);
+ pr_debug("rc=%d\n", rc);
return rc;
}
EXPORT_SYMBOL(ap_bus_force_rescan);
@@ -1043,7 +1057,7 @@ static int ap_bus_cfg_chg(struct notifier_block *nb,
if (action != CHSC_NOTIFY_AP_CFG)
return NOTIFY_DONE;
- pr_debug("%s config change, forcing bus rescan\n", __func__);
+ pr_debug("config change, forcing bus rescan\n");
ap_bus_force_rescan();
@@ -1900,8 +1914,8 @@ static inline void ap_scan_domains(struct ap_card *ac)
aq->last_err_rc = AP_RESPONSE_CHECKSTOPPED;
}
spin_unlock_bh(&aq->lock);
- pr_debug("%s(%d,%d) queue dev checkstop on\n",
- __func__, ac->id, dom);
+ pr_debug("(%d,%d) queue dev checkstop on\n",
+ ac->id, dom);
/* 'receive' pending messages with -EAGAIN */
ap_flush_queue(aq);
goto put_dev_and_continue;
@@ -1911,8 +1925,8 @@ static inline void ap_scan_domains(struct ap_card *ac)
if (aq->dev_state > AP_DEV_STATE_UNINITIATED)
_ap_queue_init_state(aq);
spin_unlock_bh(&aq->lock);
- pr_debug("%s(%d,%d) queue dev checkstop off\n",
- __func__, ac->id, dom);
+ pr_debug("(%d,%d) queue dev checkstop off\n",
+ ac->id, dom);
goto put_dev_and_continue;
}
/* config state change */
@@ -1924,8 +1938,8 @@ static inline void ap_scan_domains(struct ap_card *ac)
aq->last_err_rc = AP_RESPONSE_DECONFIGURED;
}
spin_unlock_bh(&aq->lock);
- pr_debug("%s(%d,%d) queue dev config off\n",
- __func__, ac->id, dom);
+ pr_debug("(%d,%d) queue dev config off\n",
+ ac->id, dom);
ap_send_config_uevent(&aq->ap_dev, aq->config);
/* 'receive' pending messages with -EAGAIN */
ap_flush_queue(aq);
@@ -1936,8 +1950,8 @@ static inline void ap_scan_domains(struct ap_card *ac)
if (aq->dev_state > AP_DEV_STATE_UNINITIATED)
_ap_queue_init_state(aq);
spin_unlock_bh(&aq->lock);
- pr_debug("%s(%d,%d) queue dev config on\n",
- __func__, ac->id, dom);
+ pr_debug("(%d,%d) queue dev config on\n",
+ ac->id, dom);
ap_send_config_uevent(&aq->ap_dev, aq->config);
goto put_dev_and_continue;
}
@@ -2009,8 +2023,8 @@ static inline void ap_scan_adapter(int ap)
ap_scan_rm_card_dev_and_queue_devs(ac);
put_device(dev);
} else {
- pr_debug("%s(%d) no type info (no APQN found), ignored\n",
- __func__, ap);
+ pr_debug("(%d) no type info (no APQN found), ignored\n",
+ ap);
}
return;
}
@@ -2022,8 +2036,7 @@ static inline void ap_scan_adapter(int ap)
ap_scan_rm_card_dev_and_queue_devs(ac);
put_device(dev);
} else {
- pr_debug("%s(%d) no valid type (0) info, ignored\n",
- __func__, ap);
+ pr_debug("(%d) no valid type (0) info, ignored\n", ap);
}
return;
}
@@ -2202,7 +2215,7 @@ static bool ap_scan_bus(void)
bool config_changed;
int ap;
- pr_debug(">%s\n", __func__);
+ pr_debug(">\n");
/* (re-)fetch configuration via QCI */
config_changed = ap_get_configuration();
@@ -2243,7 +2256,7 @@ static bool ap_scan_bus(void)
}
if (atomic64_inc_return(&ap_scan_bus_count) == 1) {
- pr_debug("%s init scan complete\n", __func__);
+ pr_debug("init scan complete\n");
ap_send_init_scan_done_uevent();
}
@@ -2251,7 +2264,7 @@ static bool ap_scan_bus(void)
mod_timer(&ap_scan_bus_timer, jiffies + ap_scan_bus_time * HZ);
- pr_debug("<%s config_changed=%d\n", __func__, config_changed);
+ pr_debug("< config_changed=%d\n", config_changed);
return config_changed;
}
@@ -2284,7 +2297,9 @@ static void ap_scan_bus_wq_callback(struct work_struct *unused)
* system_long_wq which invokes this function here again.
*/
if (mutex_trylock(&ap_scan_bus_mutex)) {
+ ap_scan_bus_task = current;
ap_scan_bus_result = ap_scan_bus();
+ ap_scan_bus_task = NULL;
mutex_unlock(&ap_scan_bus_mutex);
}
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-06 00:23:15 +0100