pcmcia: delay re-scanning and re-querying of PCMCIA bus

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.

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

1 files changed, 48 insertions, 32 deletions

diff --git a/drivers/pcmcia/ds.c b/drivers/pcmcia/ds.c
index 76a21638291b..5400e20c664e 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);
@@ -660,7 +668,7 @@ static void pcmcia_delayed_add_device(struct work_struct *work)
         pcmcia_device_add(s, mfc_pfc);
 }
 
-static int pcmcia_requery(struct device *dev, void * _data)
+static int pcmcia_requery_callback(struct device *dev, void * _data)
 {
         struct pcmcia_device *p_dev = to_pcmcia_dev(dev);
         if (!p_dev->dev.driver) {
@@ -671,44 +679,57 @@ 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_requery(struct pcmcia_socket *s)
 {
-        int no_devices = 0;
-        int ret = 0;
-
-        /* must be called with skt_mutex held */
-        dev_dbg(&skt->dev, "re-scanning socket %d\n", skt->sock);
+        int present;
 
-        mutex_lock(&skt->ops_mutex);
-        if (list_empty(&skt->devices_list))
-                no_devices = 1;
-        mutex_unlock(&skt->ops_mutex);
+        mutex_lock(&s->ops_mutex);
+        present = s->pcmcia_state.present;
+        mutex_unlock(&s->ops_mutex);
 
-        /* If this is because of a CIS override, start over */
-        if (new_cis && !no_devices)
-                pcmcia_card_remove(skt, NULL);
+        if (!present)
+                return;
 
-        /* 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;
+        if (s->functions == 0) {
+                pcmcia_card_add(s);
+                return;
         }
 
         /* 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);
+        bus_for_each_dev(&pcmcia_bus_type, NULL, NULL, pcmcia_requery_callback);
+
+        /* if the CIS changed, we need to check whether the number of
+         * functions changed. */
+        if (s->fake_cis) {
+                int old_funcs, new_funcs;
+                cistpl_longlink_mfc_t mfc;
+
+                /* does this cis override add or remove functions? */
+                old_funcs = s->functions;
+
+                if (!pccard_read_tuple(s, BIND_FN_ALL, CISTPL_LONGLINK_MFC,
+                                        &mfc))
+                        new_funcs = mfc.nfn;
+                else
+                        new_funcs = 1;
+                if (old_funcs > new_funcs) {
+                        pcmcia_card_remove(s, NULL);
+                        pcmcia_card_add(s);
+                } else if (new_funcs > old_funcs) {
+                        s->functions = new_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)
-                printk(KERN_INFO "pcmcia: bus_rescan_devices failed\n");
+        if (bus_rescan_devices(&pcmcia_bus_type))
+                dev_warn(&s->dev, "rescanning the bus failed\n");
 }
 
+
 #ifdef CONFIG_PCMCIA_LOAD_CIS
 
 /**
@@ -1085,7 +1106,6 @@ 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;
@@ -1093,11 +1113,7 @@ static ssize_t pcmcia_store_allow_func_id_match(struct device *dev,
         mutex_lock(&p_dev->socket->ops_mutex);
         p_dev->allow_func_id_match = 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");
+        pcmcia_parse_uevents(p_dev->socket, PCMCIA_UEVENT_REQUERY);
 
         return count;
 }
@@ -1359,7 +1375,7 @@ EXPORT_SYMBOL(pcmcia_dev_present);
 static struct pcmcia_callback pcmcia_bus_callback = {
         .owner = THIS_MODULE,
         .event = ds_event,
-        .requery = pcmcia_bus_rescan,
+        .requery = pcmcia_requery,
         .validate = pccard_validate_cis,
         .suspend = pcmcia_bus_suspend,
         .resume = pcmcia_bus_resume,