pcmcia: simplify locking
Dominik Brodowski [Sat, 16 Jan 2010 08:14:11 +0000 (09:14 +0100)]
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
drivers/pcmcia/cs_internal.h
drivers/pcmcia/ds.c
drivers/pcmcia/pcmcia_ioctl.c
drivers/pcmcia/rsrc_mgr.c
drivers/pcmcia/socket_sysfs.c
include/pcmcia/ss.h

index cc0ba8a..13277ee 100644 (file)
@@ -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
index 76ac444..bd386d7 100644 (file)
@@ -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);
 
index 0eb242c..4c40db8 100644 (file)
@@ -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);
index f73fd5b..db2e3db 100644 (file)
@@ -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) {
index cdd30c1..b815866 100644 (file)
 
 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;
 }
index 1cba9d3..e8826df 100644 (file)
@@ -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) &&
index e756069..cfaccc2 100644 (file)
@@ -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;