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>

7 files changed, 51 insertions, 77 deletions

diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
index cc0ba8aef59e..13277eebe46a 100644
--- a/drivers/pcmcia/cs.c
+++ b/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
diff --git a/drivers/pcmcia/cs_internal.h b/drivers/pcmcia/cs_internal.h
index 76ac4444f0e0..bd386d77845e 100644
--- a/drivers/pcmcia/cs_internal.h
+++ b/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);
 
diff --git a/drivers/pcmcia/ds.c b/drivers/pcmcia/ds.c
index 0eb242cbed17..4c40db8889d9 100644
--- a/drivers/pcmcia/ds.c
+++ b/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);
diff --git a/drivers/pcmcia/pcmcia_ioctl.c b/drivers/pcmcia/pcmcia_ioctl.c
index f73fd5beaa37..db2e3db8008b 100644
--- a/drivers/pcmcia/pcmcia_ioctl.c
+++ b/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) {
diff --git a/drivers/pcmcia/rsrc_mgr.c b/drivers/pcmcia/rsrc_mgr.c
index cdd30c180066..b81586622d02 100644
--- a/drivers/pcmcia/rsrc_mgr.c
+++ b/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;
 }
diff --git a/drivers/pcmcia/socket_sysfs.c b/drivers/pcmcia/socket_sysfs.c
index 1cba9d38d813..e8826df00a36 100644
--- a/drivers/pcmcia/socket_sysfs.c
+++ b/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) &&
diff --git a/include/pcmcia/ss.h b/include/pcmcia/ss.h
index e756069859b5..cfaccc224b50 100644
--- a/include/pcmcia/ss.h
+++ b/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;