pcmcia: simplify locking

replace pcmcia_socket->lock and pcmcia_dev_list_lock by using the
per-socket "ops_mutex", as we do neither need different locks
nor a spinlock here.

Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

drivers/pcmcia/cs.c

@@ -175,8 +175,6 @@ int pcmcia_register_socket(struct pcmcia_socket *socket)
 
 	dev_dbg(&socket->dev, "pcmcia_register_socket(0x%p)\n", socket->ops);
 
-	spin_lock_init(&socket->lock);
-
 	/* try to obtain a socket number [yes, it gets ugly if we
 	 * register more than 2^sizeof(unsigned int) pcmcia
 	 * sockets... but the socket number is deprecated

drivers/pcmcia/cs_internal.h

@@ -182,8 +182,6 @@ int pccard_get_tuple_data(struct pcmcia_socket *s, tuple_t *tuple);
 
 #ifdef CONFIG_PCMCIA_IOCTL
 /* ds.c */
-extern spinlock_t pcmcia_dev_list_lock;
-
 extern struct pcmcia_device *pcmcia_get_dev(struct pcmcia_device *p_dev);
 extern void pcmcia_put_dev(struct pcmcia_device *p_dev);
 

drivers/pcmcia/ds.c

@@ -42,8 +42,6 @@ MODULE_DESCRIPTION("PCMCIA Driver Services");
 MODULE_LICENSE("GPL");
 
 
-spinlock_t pcmcia_dev_list_lock;
-
 /*====================================================================*/
 
 static void pcmcia_check_driver(struct pcmcia_driver *p_drv)
@@ -265,7 +263,6 @@ static int pcmcia_device_probe(struct device *dev)
 	struct pcmcia_device_id *did;
 	struct pcmcia_socket *s;
 	cistpl_config_t cis_config;
-	unsigned long flags;
 	int ret = 0;
 
 	dev = get_device(dev);
@@ -316,11 +313,11 @@ static int pcmcia_device_probe(struct device *dev)
 		goto put_module;
 	}
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	if (did && (did->match_flags & PCMCIA_DEV_ID_MATCH_DEVICE_NO) &&
 	    (p_dev->socket->device_count == 1) && (p_dev->device_no == 0))
 		pcmcia_add_device_later(p_dev->socket, 0);
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 put_module:
 	if (ret)
@@ -339,28 +336,27 @@ static void pcmcia_card_remove(struct pcmcia_socket *s, struct pcmcia_device *le
 {
 	struct pcmcia_device	*p_dev;
 	struct pcmcia_device	*tmp;
-	unsigned long		flags;
 
 	dev_dbg(leftover ? &leftover->dev : &s->dev,
 		   "pcmcia_card_remove(%d) %s\n", s->sock,
 		   leftover ? leftover->devname : "");
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	if (!leftover)
 		s->device_count = 0;
 	else
 		s->device_count = 1;
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	/* unregister all pcmcia_devices registered with this socket, except leftover */
 	list_for_each_entry_safe(p_dev, tmp, &s->devices_list, socket_device_list) {
 		if (p_dev == leftover)
 			continue;
 
-		spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+		mutex_lock(&s->ops_mutex);
 		list_del(&p_dev->socket_device_list);
 		p_dev->_removed = 1;
-		spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+		mutex_unlock(&s->ops_mutex);
 
 		dev_dbg(&p_dev->dev, "unregistering device\n");
 		device_unregister(&p_dev->dev);
@@ -507,7 +503,6 @@ static DEFINE_MUTEX(device_add_lock);
 struct pcmcia_device *pcmcia_device_add(struct pcmcia_socket *s, unsigned int function)
 {
 	struct pcmcia_device *p_dev, *tmp_dev;
-	unsigned long flags;
 
 	s = pcmcia_get_socket(s);
 	if (!s)
@@ -521,9 +516,9 @@ struct pcmcia_device *pcmcia_device_add(struct pcmcia_socket *s, unsigned int fu
 	if (!p_dev)
 		goto err_put;
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	p_dev->device_no = (s->device_count++);
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	/* max of 4 devices per card */
 	if (p_dev->device_no >= 4)
@@ -546,7 +541,7 @@ struct pcmcia_device *pcmcia_device_add(struct pcmcia_socket *s, unsigned int fu
 		goto err_free;
 	dev_dbg(&p_dev->dev, "devname is %s\n", p_dev->devname);
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 
 	/*
 	 * p_dev->function_config must be the same for all card functions.
@@ -564,7 +559,7 @@ struct pcmcia_device *pcmcia_device_add(struct pcmcia_socket *s, unsigned int fu
 	/* Add to the list in pcmcia_bus_socket */
 	list_add(&p_dev->socket_device_list, &s->devices_list);
 
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	if (!p_dev->function_config) {
 		dev_dbg(&p_dev->dev, "creating config_t\n");
@@ -589,14 +584,14 @@ struct pcmcia_device *pcmcia_device_add(struct pcmcia_socket *s, unsigned int fu
 	return p_dev;
 
  err_unreg:
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	list_del(&p_dev->socket_device_list);
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
  err_free:
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	s->device_count--;
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	kfree(p_dev->devname);
 	kfree(p_dev);
@@ -650,13 +645,12 @@ static void pcmcia_delayed_add_device(struct work_struct *work)
 	struct pcmcia_socket *s =
 		container_of(work, struct pcmcia_socket, device_add);
 	u8 mfc_pfc;
-	unsigned long flags;
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	mfc_pfc = s->pcmcia_state.mfc_pfc;
 	s->pcmcia_state.device_add_pending = 0;
 	s->pcmcia_state.mfc_pfc = 0;
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	dev_dbg(&s->dev, "adding additional device to %d\n", s->sock);
 	pcmcia_device_add(s, mfc_pfc);
@@ -677,15 +671,14 @@ static void pcmcia_bus_rescan(struct pcmcia_socket *skt, int new_cis)
 {
 	int no_devices = 0;
 	int ret = 0;
-	unsigned long flags;
 
 	/* must be called with skt_mutex held */
 	dev_dbg(&skt->dev, "re-scanning socket %d\n", skt->sock);
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&skt->ops_mutex);
 	if (list_empty(&skt->devices_list))
 		no_devices = 1;
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&skt->ops_mutex);
 
 	/* If this is because of a CIS override, start over */
 	if (new_cis && !no_devices)
@@ -769,11 +762,9 @@ static int pcmcia_load_firmware(struct pcmcia_device *dev, char * filename)
 		if (old_funcs > no_funcs)
 			pcmcia_card_remove(s, dev);
 		else if (no_funcs > old_funcs) {
-			unsigned long flags;
-
-			spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+			mutex_lock(&s->ops_mutex);
 			pcmcia_add_device_later(s, 1);
-			spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+			mutex_unlock(&s->ops_mutex);
 		}
 	}
  release:
@@ -1248,7 +1239,6 @@ static int pcmcia_bus_suspend(struct pcmcia_socket *skt)
 static int ds_event(struct pcmcia_socket *skt, event_t event, int priority)
 {
 	struct pcmcia_socket *s = pcmcia_get_socket(skt);
-	unsigned long flags;
 
 	if (!s) {
 		dev_printk(KERN_ERR, &skt->dev,
@@ -1262,9 +1252,9 @@ static int ds_event(struct pcmcia_socket *skt, event_t event, int priority)
 
 	switch (event) {
 	case CS_EVENT_CARD_REMOVAL:
-		spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+		mutex_lock(&s->ops_mutex);
 		s->pcmcia_state.present = 0;
-		spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+		mutex_unlock(&s->ops_mutex);
 		pcmcia_card_remove(skt, NULL);
 		handle_event(skt, event);
 		mutex_lock(&s->ops_mutex);
@@ -1273,10 +1263,8 @@ static int ds_event(struct pcmcia_socket *skt, event_t event, int priority)
 		break;
 
 	case CS_EVENT_CARD_INSERTION:
-		spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
-		s->pcmcia_state.present = 1;
-		spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
 		mutex_lock(&s->ops_mutex);
+		s->pcmcia_state.present = 1;
 		destroy_cis_cache(s); /* to be on the safe side... */
 		mutex_unlock(&s->ops_mutex);
 		pcmcia_card_add(skt);
@@ -1321,13 +1309,12 @@ struct pcmcia_device *pcmcia_dev_present(struct pcmcia_device *_p_dev)
 {
 	struct pcmcia_device *p_dev;
 	struct pcmcia_device *ret = NULL;
-	unsigned long flags;
 
 	p_dev = pcmcia_get_dev(_p_dev);
 	if (!p_dev)
 		return NULL;
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&p_dev->socket->ops_mutex);
 	if (!p_dev->socket->pcmcia_state.present)
 		goto out;
 
@@ -1342,7 +1329,7 @@ struct pcmcia_device *pcmcia_dev_present(struct pcmcia_device *_p_dev)
 
 	ret = p_dev;
  out:
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&p_dev->socket->ops_mutex);
 	pcmcia_put_dev(p_dev);
 	return ret;
 }
@@ -1406,14 +1393,13 @@ static void pcmcia_bus_remove_socket(struct device *dev,
 				     struct class_interface *class_intf)
 {
 	struct pcmcia_socket *socket = dev_get_drvdata(dev);
-	unsigned long flags;
 
 	if (!socket)
 		return;
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&socket->ops_mutex);
 	socket->pcmcia_state.dead = 1;
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&socket->ops_mutex);
 
 	pccard_register_pcmcia(socket, NULL);
 
@@ -1455,8 +1441,6 @@ static int __init init_pcmcia_bus(void)
 {
 	int ret;
 
-	spin_lock_init(&pcmcia_dev_list_lock);
-
 	ret = bus_register(&pcmcia_bus_type);
 	if (ret < 0) {
 		printk(KERN_WARNING "pcmcia: bus_register error: %d\n", ret);

drivers/pcmcia/pcmcia_ioctl.c

@@ -62,16 +62,15 @@ static struct pcmcia_device *get_pcmcia_device(struct pcmcia_socket *s,
 						unsigned int function)
 {
 	struct pcmcia_device *p_dev = NULL;
-	unsigned long flags;
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	list_for_each_entry(p_dev, &s->devices_list, socket_device_list) {
 		if (p_dev->func == function) {
-			spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+			mutex_unlock(&s->ops_mutex);
 			return pcmcia_get_dev(p_dev);
 		}
 	}
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 	return NULL;
 }
 
@@ -169,7 +168,6 @@ static int pcmcia_adjust_resource_info(adjust_t *adj)
 {
 	struct pcmcia_socket *s;
 	int ret = -ENOSYS;
-	unsigned long flags;
 
 	down_read(&pcmcia_socket_list_rwsem);
 	list_for_each_entry(s, &pcmcia_socket_list, socket_list) {
@@ -182,14 +180,14 @@ static int pcmcia_adjust_resource_info(adjust_t *adj)
 
 			/* you can't use the old interface if the new
 			 * one was used before */
-			spin_lock_irqsave(&s->lock, flags);
+			mutex_lock(&s->ops_mutex);
 			if ((s->resource_setup_new) &&
 			    !(s->resource_setup_old)) {
-				spin_unlock_irqrestore(&s->lock, flags);
+				mutex_unlock(&s->ops_mutex);
 				continue;
 			} else if (!(s->resource_setup_old))
 				s->resource_setup_old = 1;
-			spin_unlock_irqrestore(&s->lock, flags);
+			mutex_unlock(&s->ops_mutex);
 
 			switch (adj->Resource) {
 			case RES_MEMORY_RANGE:
@@ -208,9 +206,9 @@ static int pcmcia_adjust_resource_info(adjust_t *adj)
 				 * last call to adjust_resource_info, we
 				 * always need to assume this is the latest
 				 * one... */
-				spin_lock_irqsave(&s->lock, flags);
+				mutex_lock(&s->ops_mutex);
 				s->resource_setup_done = 1;
-				spin_unlock_irqrestore(&s->lock, flags);
+				mutex_unlock(&s->ops_mutex);
 			}
 		}
 	}
@@ -470,7 +468,6 @@ static int bind_request(struct pcmcia_socket *s, bind_info_t *bind_info)
 	struct pcmcia_driver *p_drv;
 	struct pcmcia_device *p_dev;
 	int ret = 0;
-	unsigned long flags;
 
 	s = pcmcia_get_socket(s);
 	if (!s)
@@ -490,7 +487,7 @@ static int bind_request(struct pcmcia_socket *s, bind_info_t *bind_info)
 		goto err_put_driver;
 	}
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	list_for_each_entry(p_dev, &s->devices_list, socket_device_list) {
 		if (p_dev->func == bind_info->function) {
 			if ((p_dev->dev.driver == &p_drv->drv)) {
@@ -499,7 +496,7 @@ static int bind_request(struct pcmcia_socket *s, bind_info_t *bind_info)
 					 * registered, and it was registered
 					 * by userspace before, we need to
 					 * return the "instance". */
-					spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+					mutex_unlock(&s->ops_mutex);
 					bind_info->instance = p_dev;
 					ret = -EBUSY;
 					goto err_put_module;
@@ -507,7 +504,7 @@ static int bind_request(struct pcmcia_socket *s, bind_info_t *bind_info)
 					/* the correct driver managed to bind
 					 * itself magically to the correct
 					 * device. */
-					spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+					mutex_unlock(&s->ops_mutex);
 					p_dev->cardmgr = p_drv;
 					ret = 0;
 					goto err_put_module;
@@ -516,12 +513,12 @@ static int bind_request(struct pcmcia_socket *s, bind_info_t *bind_info)
 				/* there's already a device available where
 				 * no device has been bound to yet. So we don't
 				 * need to register a device! */
-				spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+				mutex_unlock(&s->ops_mutex);
 				goto rescan;
 			}
 		}
 	}
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	p_dev = pcmcia_device_add(s, bind_info->function);
 	if (!p_dev) {
@@ -578,7 +575,6 @@ static int get_device_info(struct pcmcia_socket *s, bind_info_t *bind_info, int
 	dev_node_t *node;
 	struct pcmcia_device *p_dev;
 	struct pcmcia_driver *p_drv;
-	unsigned long flags;
 	int ret = 0;
 
 #ifdef CONFIG_CARDBUS
@@ -617,7 +613,7 @@ static int get_device_info(struct pcmcia_socket *s, bind_info_t *bind_info, int
 	}
 #endif
 
-	spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+	mutex_lock(&s->ops_mutex);
 	list_for_each_entry(p_dev, &s->devices_list, socket_device_list) {
 		if (p_dev->func == bind_info->function) {
 			p_dev = pcmcia_get_dev(p_dev);
@@ -626,11 +622,11 @@ static int get_device_info(struct pcmcia_socket *s, bind_info_t *bind_info, int
 			goto found;
 		}
 	}
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 	return -ENODEV;
 
  found:
-	spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	p_drv = to_pcmcia_drv(p_dev->dev.driver);
 	if (p_drv && !p_dev->_locked) {

drivers/pcmcia/rsrc_mgr.c

@@ -23,14 +23,12 @@
 
 static int static_init(struct pcmcia_socket *s)
 {
-	unsigned long flags;
-
 	/* the good thing about SS_CAP_STATIC_MAP sockets is
 	 * that they don't need a resource database */
 
-	spin_lock_irqsave(&s->lock, flags);
+	mutex_lock(&s->ops_mutex);
 	s->resource_setup_done = 1;
-	spin_unlock_irqrestore(&s->lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	return 0;
 }

drivers/pcmcia/socket_sysfs.c

@@ -189,16 +189,15 @@ static ssize_t pccard_store_resource(struct device *dev,
 				     struct device_attribute *attr,
 				     const char *buf, size_t count)
 {
-	unsigned long flags;
 	struct pcmcia_socket *s = to_socket(dev);
 
 	if (!count)
 		return -EINVAL;
 
-	spin_lock_irqsave(&s->lock, flags);
+	mutex_lock(&s->ops_mutex);
 	if (!s->resource_setup_done)
 		s->resource_setup_done = 1;
-	spin_unlock_irqrestore(&s->lock, flags);
+	mutex_unlock(&s->ops_mutex);
 
 	mutex_lock(&s->skt_mutex);
 	if ((s->callback) &&

include/pcmcia/ss.h

@@ -134,7 +134,6 @@ struct pccard_operations {
 
 struct pcmcia_socket {
 	struct module			*owner;
-	spinlock_t			lock;
 	socket_state_t			socket;
 	u_int				state;
 	u_int				suspended_state;	/* state before suspend */
@@ -201,10 +200,12 @@ struct pcmcia_socket {
 	struct task_struct		*thread;
 	struct completion		thread_done;
 	unsigned int			thread_events;
-	/* protects socket h/w state */
+
+	/* For the non-trivial interaction between these locks,
+	 * see Documentation/pcmcia/locking.txt */
 	struct mutex			skt_mutex;
-	/* protects PCMCIA state */
 	struct mutex			ops_mutex;
+
 	/* protects thread_events */
 	spinlock_t			thread_lock;