eeepc-laptop: use a mutex to serialize pci hotplug (resume vs. notify)

Commit d0265f0 "eeepc-laptop: fix hot-unplug on resume" used a workqueue
to protect pci hotplug against multiple simultaneous calls during
resume.  It seems to work, but a mutex would be more appropriate.

This is in preparation to fix the potential pci hotplug race on unload.

Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 13 insertions, 8 deletions

diff --git a/drivers/platform/x86/eeepc-laptop.c b/drivers/platform/x86/eeepc-laptop.c
index 69d73ed2c8ab..179010386981 100644
--- a/drivers/platform/x86/eeepc-laptop.c
+++ b/drivers/platform/x86/eeepc-laptop.c
@@ -143,7 +143,7 @@ struct eeepc_hotk {
         struct rfkill *bluetooth_rfkill;
         struct rfkill *wwan3g_rfkill;
         struct hotplug_slot *hotplug_slot;
-        struct work_struct hotplug_work;
+        struct mutex hotplug_lock;
 };
 
 /* The actual device the driver binds to */
@@ -661,7 +661,7 @@ static int eeepc_get_adapter_status(struct hotplug_slot *hotplug_slot,
         return 0;
 }
 
-static void eeepc_hotplug_work(struct work_struct *work)
+static void eeepc_rfkill_hotplug(void)
 {
         struct pci_dev *dev;
         struct pci_bus *bus;
@@ -669,13 +669,15 @@ static void eeepc_hotplug_work(struct work_struct *work)
 
         rfkill_set_sw_state(ehotk->wlan_rfkill, blocked);
 
+        mutex_lock(&ehotk->hotplug_lock);
+
         if (ehotk->hotplug_slot == NULL)
-                return;
+                goto out_unlock;
 
         bus = pci_find_bus(0, 1);
         if (!bus) {
                 pr_warning("Unable to find PCI bus 1?\n");
-                return;
+                goto out_unlock;
         }
 
         if (!blocked) {
@@ -683,7 +685,7 @@ static void eeepc_hotplug_work(struct work_struct *work)
                 if (dev) {
                         /* Device already present */
                         pci_dev_put(dev);
-                        return;
+                        goto out_unlock;
                 }
                 dev = pci_scan_single_device(bus, 0);
                 if (dev) {
@@ -698,6 +700,9 @@ static void eeepc_hotplug_work(struct work_struct *work)
                         pci_dev_put(dev);
                 }
         }
+
+out_unlock:
+        mutex_unlock(&ehotk->hotplug_lock);
 }
 
 static void eeepc_rfkill_notify(acpi_handle handle, u32 event, void *data)
@@ -705,7 +710,7 @@ static void eeepc_rfkill_notify(acpi_handle handle, u32 event, void *data)
         if (event != ACPI_NOTIFY_BUS_CHECK)
                 return;
 
-        schedule_work(&ehotk->hotplug_work);
+        eeepc_rfkill_hotplug();
 }
 
 static void eeepc_hotk_notify(struct acpi_device *device, u32 event)
@@ -896,7 +901,7 @@ static int eeepc_hotk_resume(struct acpi_device *device)
 
                 rfkill_set_sw_state(ehotk->wlan_rfkill, wlan != 1);
 
-                schedule_work(&ehotk->hotplug_work);
+                eeepc_rfkill_hotplug();
         }
 
         if (ehotk->bluetooth_rfkill)
@@ -1097,7 +1102,7 @@ static int eeepc_rfkill_init(struct device *dev)
 {
         int result = 0;
 
-        INIT_WORK(&ehotk->hotplug_work, eeepc_hotplug_work);
+        mutex_init(&ehotk->hotplug_lock);
 
         eeepc_register_rfkill_notifier("\\_SB.PCI0.P0P6");
         eeepc_register_rfkill_notifier("\\_SB.PCI0.P0P7");