pcmcia: protect s->device_count

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

1 files changed, 18 insertions, 7 deletions

diff --git a/drivers/pcmcia/ds.c b/drivers/pcmcia/ds.c
index 4f7308df22c8..bcb9ef103427 100644
--- a/drivers/pcmcia/ds.c
+++ b/drivers/pcmcia/ds.c
@@ -265,6 +265,7 @@ 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);
@@ -315,9 +316,11 @@ static int pcmcia_device_probe(struct device *dev)
                 goto put_module;
         }
 
+        spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
         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);
 
 put_module:
         if (ret)
@@ -342,10 +345,12 @@ static void pcmcia_card_remove(struct pcmcia_socket *s, struct pcmcia_device *le
                    "pcmcia_card_remove(%d) %s\n", s->sock,
                    leftover ? leftover->devname : "");
 
+        spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
         if (!leftover)
                 s->device_count = 0;
         else
                 s->device_count = 1;
+        spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
 
         /* unregister all pcmcia_devices registered with this socket, except leftover */
         list_for_each_entry_safe(p_dev, tmp, &s->devices_list, socket_device_list) {
@@ -382,7 +387,7 @@ static int pcmcia_device_remove(struct device *dev)
          */
         did = dev_get_drvdata(&p_dev->dev);
         if (did && (did->match_flags & PCMCIA_DEV_ID_MATCH_DEVICE_NO) &&
-            (p_dev->socket->device_count != 0) &&
+            (p_dev->socket->device_count > 0) &&
             (p_dev->device_no == 0))
                 pcmcia_card_remove(p_dev->socket, p_dev);
 
@@ -512,16 +517,19 @@ struct pcmcia_device *pcmcia_device_add(struct pcmcia_socket *s, unsigned int fu
 
         pr_debug("adding device to %d, function %d\n", s->sock, function);
 
-        /* max of 4 devices per card */
-        if (s->device_count == 4)
-                goto err_put;
-
         p_dev = kzalloc(sizeof(struct pcmcia_device), GFP_KERNEL);
         if (!p_dev)
                 goto err_put;
 
-        p_dev->socket = s;
+        spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
         p_dev->device_no = (s->device_count++);
+        spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+
+        /* max of 4 devices per card */
+        if (p_dev->device_no >= 4)
+                goto err_free;
+
+        p_dev->socket = s;
         p_dev->func   = function;
 
         p_dev->dev.bus = &pcmcia_bus_type;
@@ -586,9 +594,12 @@ struct pcmcia_device *pcmcia_device_add(struct pcmcia_socket *s, unsigned int fu
         spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
 
  err_free:
+        spin_lock_irqsave(&pcmcia_dev_list_lock, flags);
+        s->device_count--;
+        spin_unlock_irqrestore(&pcmcia_dev_list_lock, flags);
+
         kfree(p_dev->devname);
         kfree(p_dev);
-        s->device_count--;
  err_put:
         mutex_unlock(&device_add_lock);
         pcmcia_put_socket(s);