[PATCH 12/16] pcmcia: delay re-scanning and re-querying of PCMCIA bus

Dominik Brodowski linux at dominikbrodowski.net
Mon Jan 18 03:36:32 EST 2010


After a CIS update -- or the finalization of the resource database --,
proceed with the re-scanning or re-querying of PCMCIA cards only in
a separate thread to avoid deadlocks.

Signed-off-by: Dominik Brodowski <linux at dominikbrodowski.net>
---
 drivers/pcmcia/cistpl.c       |   13 ++----
 drivers/pcmcia/cs_internal.h  |    1 -
 drivers/pcmcia/ds.c           |   90 ++++++++++++++++++++++++++---------------
 drivers/pcmcia/socket_sysfs.c |   17 +++-----
 include/pcmcia/ss.h           |    9 ++++-
 5 files changed, 77 insertions(+), 53 deletions(-)

diff --git a/drivers/pcmcia/cistpl.c b/drivers/pcmcia/cistpl.c
index 14de287..79db80f 100644
--- a/drivers/pcmcia/cistpl.c
+++ b/drivers/pcmcia/cistpl.c
@@ -1670,15 +1670,12 @@ static ssize_t pccard_store_cis(struct kobject *kobj,
 	if (error)
 		return -EIO;
 
-	mutex_lock(&s->skt_mutex);
-	if ((s->callback) && (s->state & SOCKET_PRESENT) &&
-	    !(s->state & SOCKET_CARDBUS)) {
-		if (try_module_get(s->callback->owner)) {
-			s->callback->requery(s, 1);
-			module_put(s->callback->owner);
-		}
+	mutex_lock(&s->ops_mutex);
+	if (!s->pcmcia_state.requery_pending) {
+		schedule_work(&s->requery);
+		s->pcmcia_state.requery_pending = 1;
 	}
-	mutex_unlock(&s->skt_mutex);
+	mutex_unlock(&s->ops_mutex);
 
 	return count;
 }
diff --git a/drivers/pcmcia/cs_internal.h b/drivers/pcmcia/cs_internal.h
index 9625bf2..c07041e 100644
--- a/drivers/pcmcia/cs_internal.h
+++ b/drivers/pcmcia/cs_internal.h
@@ -116,7 +116,6 @@ struct pcmcia_callback{
 	struct module	*owner;
 	int		(*event) (struct pcmcia_socket *s,
 				  event_t event, int priority);
-	void		(*requery) (struct pcmcia_socket *s, int new_cis);
 	int		(*validate) (struct pcmcia_socket *s, unsigned int *i);
 	int		(*suspend) (struct pcmcia_socket *s);
 	int		(*resume) (struct pcmcia_socket *s);
diff --git a/drivers/pcmcia/ds.c b/drivers/pcmcia/ds.c
index 253d9ac..d61f3f1 100644
--- a/drivers/pcmcia/ds.c
+++ b/drivers/pcmcia/ds.c
@@ -432,16 +432,20 @@ static int pcmcia_device_query(struct pcmcia_device *p_dev)
 
 	if (!pccard_read_tuple(p_dev->socket, BIND_FN_ALL,
 			       CISTPL_MANFID, &manf_id)) {
+		mutex_lock(&p_dev->socket->ops_mutex);
 		p_dev->manf_id = manf_id.manf;
 		p_dev->card_id = manf_id.card;
 		p_dev->has_manf_id = 1;
 		p_dev->has_card_id = 1;
+		mutex_unlock(&p_dev->socket->ops_mutex);
 	}
 
 	if (!pccard_read_tuple(p_dev->socket, p_dev->func,
 			       CISTPL_FUNCID, &func_id)) {
+		mutex_lock(&p_dev->socket->ops_mutex);
 		p_dev->func_id = func_id.func;
 		p_dev->has_func_id = 1;
+		mutex_unlock(&p_dev->socket->ops_mutex);
 	} else {
 		/* rule of thumb: cards with no FUNCID, but with
 		 * common memory device geometry information, are
@@ -458,14 +462,17 @@ static int pcmcia_device_query(struct pcmcia_device *p_dev)
 			dev_dbg(&p_dev->dev,
 				   "mem device geometry probably means "
 				   "FUNCID_MEMORY\n");
+			mutex_lock(&p_dev->socket->ops_mutex);
 			p_dev->func_id = CISTPL_FUNCID_MEMORY;
 			p_dev->has_func_id = 1;
+			mutex_unlock(&p_dev->socket->ops_mutex);
 		}
 		kfree(devgeo);
 	}
 
 	if (!pccard_read_tuple(p_dev->socket, BIND_FN_ALL, CISTPL_VERS_1,
 			       vers1)) {
+		mutex_lock(&p_dev->socket->ops_mutex);
 		for (i = 0; i < min_t(unsigned int, 4, vers1->ns); i++) {
 			char *tmp;
 			unsigned int length;
@@ -484,6 +491,7 @@ static int pcmcia_device_query(struct pcmcia_device *p_dev)
 			p_dev->prod_id[i] = strncpy(p_dev->prod_id[i],
 						    tmp, length);
 		}
+		mutex_unlock(&p_dev->socket->ops_mutex);
 	}
 
 	kfree(vers1);
@@ -667,44 +675,57 @@ static int pcmcia_requery(struct device *dev, void * _data)
 	return 0;
 }
 
-static void pcmcia_bus_rescan(struct pcmcia_socket *skt, int new_cis)
+static void pcmcia_delayed_requery(struct work_struct *work)
 {
-	int no_devices = 0;
-	int ret = 0;
+	int old_funcs;
 
-	/* must be called with skt_mutex held */
-	dev_dbg(&skt->dev, "re-scanning socket %d\n", skt->sock);
+	struct pcmcia_socket *s =
+		container_of(work, struct pcmcia_socket, requery);
 
-	mutex_lock(&skt->ops_mutex);
-	if (list_empty(&skt->devices_list))
-		no_devices = 1;
-	mutex_unlock(&skt->ops_mutex);
+	mutex_lock(&s->skt_mutex);
 
-	/* If this is because of a CIS override, start over */
-	if (new_cis && !no_devices)
-		pcmcia_card_remove(skt, NULL);
-
-	/* if no devices were added for this socket yet because of
-	 * missing resource information or other trouble, we need to
-	 * do this now. */
-	if (no_devices || new_cis) {
-		ret = pcmcia_card_add(skt);
-		if (ret)
-			return;
-	}
+	/* does this cis override add or remove functions? */
+	old_funcs = s->functions;
 
 	/* some device information might have changed because of a CIS
 	 * update or because we can finally read it correctly... so
 	 * determine it again, overwriting old values if necessary. */
 	bus_for_each_dev(&pcmcia_bus_type, NULL, NULL, pcmcia_requery);
 
-	/* we re-scan all devices, not just the ones connected to this
-	 * socket. This does not matter, though. */
-	ret = bus_rescan_devices(&pcmcia_bus_type);
-	if (ret)
-		printk(KERN_INFO "pcmcia: bus_rescan_devices failed\n");
+	if (old_funcs == 0)
+		pcmcia_card_add(s);
+	else {
+		cistpl_longlink_mfc_t mfc;
+		int no_funcs;
+		int ret;
+
+		if (!pccard_read_tuple(s, BIND_FN_ALL, CISTPL_LONGLINK_MFC,
+					&mfc))
+			no_funcs = mfc.nfn;
+		else
+			no_funcs = 1;
+		s->functions = no_funcs;
+
+		if (old_funcs > no_funcs) {
+			pcmcia_card_remove(s, NULL);
+			pcmcia_card_add(s);
+		} else if (no_funcs > old_funcs)
+			pcmcia_device_add(s, 1);
+
+		/* we re-scan all devices, not just the ones connected to this
+		 * socket. This does not matter, though. */
+		ret = bus_rescan_devices(&pcmcia_bus_type);
+		if (ret)
+			dev_warn(&s->dev, "rescanning the bus failed\n");
+	}
+	mutex_lock(&s->ops_mutex);
+	s->pcmcia_state.requery_pending = 0;
+	mutex_unlock(&s->ops_mutex);
+
+	mutex_unlock(&s->skt_mutex);
 }
 
+
 #ifdef CONFIG_PCMCIA_LOAD_CIS
 
 /**
@@ -1081,20 +1102,18 @@ static ssize_t pcmcia_store_allow_func_id_match(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct pcmcia_device *p_dev = to_pcmcia_dev(dev);
-	int ret;
 
 	if (!count)
 		return -EINVAL;
 
 	mutex_lock(&p_dev->socket->ops_mutex);
 	p_dev->allow_func_id_match = 1;
+	if (!p_dev->socket->pcmcia_state.requery_pending) {
+		schedule_work(&p_dev->socket->requery);
+		p_dev->socket->pcmcia_state.requery_pending = 1;
+	}
 	mutex_unlock(&p_dev->socket->ops_mutex);
 
-	ret = bus_rescan_devices(&pcmcia_bus_type);
-	if (ret)
-		printk(KERN_INFO "pcmcia: bus_rescan_devices failed after "
-		       "allowing func_id matches\n");
-
 	return count;
 }
 
@@ -1355,7 +1374,6 @@ EXPORT_SYMBOL(pcmcia_dev_present);
 static struct pcmcia_callback pcmcia_bus_callback = {
 	.owner = THIS_MODULE,
 	.event = ds_event,
-	.requery = pcmcia_bus_rescan,
 	.validate = pccard_validate_cis,
 	.suspend = pcmcia_bus_suspend,
 	.resume = pcmcia_bus_resume,
@@ -1392,6 +1410,7 @@ static int __devinit pcmcia_bus_add_socket(struct device *dev,
 #endif
 	INIT_LIST_HEAD(&socket->devices_list);
 	INIT_WORK(&socket->device_add, pcmcia_delayed_add_device);
+	INIT_WORK(&socket->requery, pcmcia_delayed_requery);
 	memset(&socket->pcmcia_state, 0, sizeof(u8));
 	socket->device_count = 0;
 
@@ -1402,6 +1421,10 @@ static int __devinit pcmcia_bus_add_socket(struct device *dev,
 		return ret;
 	}
 
+	mutex_lock(&socket->ops_mutex);
+	socket->pcmcia_state.requery_allowed = 1;
+	mutex_unlock(&socket->ops_mutex);
+
 	return 0;
 }
 
@@ -1415,6 +1438,7 @@ static void pcmcia_bus_remove_socket(struct device *dev,
 
 	mutex_lock(&socket->ops_mutex);
 	socket->pcmcia_state.dead = 1;
+	socket->pcmcia_state.requery_allowed = 0;
 	mutex_unlock(&socket->ops_mutex);
 
 	pccard_register_pcmcia(socket, NULL);
diff --git a/drivers/pcmcia/socket_sysfs.c b/drivers/pcmcia/socket_sysfs.c
index e8826df..aadf83d 100644
--- a/drivers/pcmcia/socket_sysfs.c
+++ b/drivers/pcmcia/socket_sysfs.c
@@ -194,21 +194,18 @@ static ssize_t pccard_store_resource(struct device *dev,
 	if (!count)
 		return -EINVAL;
 
+#if defined(CONFIG_PCMCIA) || defined(CONFIG_PCMCIA_MODULE)
 	mutex_lock(&s->ops_mutex);
 	if (!s->resource_setup_done)
 		s->resource_setup_done = 1;
-	mutex_unlock(&s->ops_mutex);
 
-	mutex_lock(&s->skt_mutex);
-	if ((s->callback) &&
-	    (s->state & SOCKET_PRESENT) &&
-	    !(s->state & SOCKET_CARDBUS)) {
-		if (try_module_get(s->callback->owner)) {
-			s->callback->requery(s, 0);
-			module_put(s->callback->owner);
-		}
+	if ((s->pcmcia_state.requery_allowed) &&
+	    (!s->pcmcia_state.requery_pending)) {
+		schedule_work(&s->requery);
+		s->pcmcia_state.requery_pending = 1;
 	}
-	mutex_unlock(&s->skt_mutex);
+	mutex_unlock(&s->ops_mutex);
+#endif
 
 	return count;
 }
diff --git a/include/pcmcia/ss.h b/include/pcmcia/ss.h
index cfaccc2..e197adb 100644
--- a/include/pcmcia/ss.h
+++ b/include/pcmcia/ss.h
@@ -231,16 +231,23 @@ struct pcmcia_socket {
 		u8			dead:1;
 		/* a multifunction-device add event is pending */
 		u8			device_add_pending:1;
+		/* a requery event is pending */
+		u8			requery_pending:1;
+		/* a requery event is pending */
+		u8			requery_allowed:1;
 		/* the pending event adds a mfc (1) or pfc (0) */
 		u8			mfc_pfc:1;
 
-		u8			reserved:3;
+		u8			reserved:1;
 	} pcmcia_state;
 
 
 	/* for adding further pseudo-multifunction devices */
 	struct work_struct		device_add;
 
+	/* for re-querying devices */
+	struct work_struct		requery;
+
 #ifdef CONFIG_PCMCIA_IOCTL
 	struct user_info_t		*user;
 	wait_queue_head_t		queue;
-- 
1.6.3.3




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