pciehp - add missing locking

This patch fixes the problem that system will panic if multiple power
on/off operations are issued to the same slot in parallel. This
problem can be easily reproduced by commands below.

    # while true; do echo 1 > power; echo 0 > power; done &
    # while true; do echo 1 > power; echo 0 > power; done &

The cause is lack of locking for enable/disable operations. This patch
fixes this problem.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 33 insertions, 30 deletions

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index b71f774aca16..30f021c55fe5 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -92,6 +92,7 @@ struct php_ctlr_state_s {
 struct controller {
         struct controller *next;
         struct mutex crit_sect;         /* critical section mutex */
+        struct mutex ctrl_lock;         /* controller lock */
         struct php_ctlr_state_s *hpc_ctlr_handle; /* HPC controller handle */
         int num_slots;                  /* Number of slots on ctlr */
         int slot_num_inc;               /* 1 or -1 */
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index c67b7c3f1ddf..f93e81e2d2c7 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -448,7 +448,7 @@ static int pciehp_probe(struct pcie_device *dev, const struct pcie_port_service_
         }
 
         /* Wait for exclusive access to hardware */
-        mutex_lock(&ctrl->crit_sect);
+        mutex_lock(&ctrl->ctrl_lock);
 
         t_slot->hpc_ops->get_adapter_status(t_slot, &value); /* Check if slot is occupied */
         
@@ -456,7 +456,7 @@ static int pciehp_probe(struct pcie_device *dev, const struct pcie_port_service_
                 rc = t_slot->hpc_ops->power_off_slot(t_slot); /* Power off slot if not occupied*/
                 if (rc) {
                         /* Done with exclusive hardware access */
-                        mutex_unlock(&ctrl->crit_sect);
+                        mutex_unlock(&ctrl->ctrl_lock);
                         goto err_out_free_ctrl_slot;
                 } else
                         /* Wait for the command to complete */
@@ -464,7 +464,7 @@ static int pciehp_probe(struct pcie_device *dev, const struct pcie_port_service_
         }
 
         /* Done with exclusive hardware access */
-        mutex_unlock(&ctrl->crit_sect);
+        mutex_unlock(&ctrl->ctrl_lock);
 
         return 0;
 
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index f602b042adcf..c206a3d63b63 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -234,13 +234,13 @@ u8 pciehp_handle_power_fault(u8 hp_slot, void *inst_id)
 static void set_slot_off(struct controller *ctrl, struct slot * pslot)
 {
         /* Wait for exclusive access to hardware */
-        mutex_lock(&ctrl->crit_sect);
+        mutex_lock(&ctrl->ctrl_lock);
 
         /* turn off slot, turn on Amber LED, turn off Green LED if supported*/
         if (POWER_CTRL(ctrl->ctrlcap)) {
                 if (pslot->hpc_ops->power_off_slot(pslot)) {   
                         err("%s: Issue of Slot Power Off command failed\n", __FUNCTION__);
-                        mutex_unlock(&ctrl->crit_sect);
+                        mutex_unlock(&ctrl->ctrl_lock);
                         return;
                 }
                 wait_for_ctrl_irq (ctrl);
@@ -254,14 +254,14 @@ static void set_slot_off(struct controller *ctrl, struct slot * pslot)
         if (ATTN_LED(ctrl->ctrlcap)) { 
                 if (pslot->hpc_ops->set_attention_status(pslot, 1)) {   
                         err("%s: Issue of Set Attention Led command failed\n", __FUNCTION__);
-                        mutex_unlock(&ctrl->crit_sect);
+                        mutex_unlock(&ctrl->ctrl_lock);
                         return;
                 }
                 wait_for_ctrl_irq (ctrl);
         }
 
         /* Done with exclusive hardware access */
-        mutex_unlock(&ctrl->crit_sect);
+        mutex_unlock(&ctrl->ctrl_lock);
 }
 
 /**
@@ -284,13 +284,13 @@ static int board_added(struct slot *p_slot)
                         ctrl->slot_device_offset, hp_slot);
 
         /* Wait for exclusive access to hardware */
-        mutex_lock(&ctrl->crit_sect);
+        mutex_lock(&ctrl->ctrl_lock);
 
         if (POWER_CTRL(ctrl->ctrlcap)) {
                 /* Power on slot */
                 rc = p_slot->hpc_ops->power_on_slot(p_slot);
                 if (rc) {
-                        mutex_unlock(&ctrl->crit_sect);
+                        mutex_unlock(&ctrl->ctrl_lock);
                         return -1;
                 }
 
@@ -306,7 +306,7 @@ static int board_added(struct slot *p_slot)
         }
 
         /* Done with exclusive hardware access */
-        mutex_unlock(&ctrl->crit_sect);
+        mutex_unlock(&ctrl->ctrl_lock);
 
         /* Wait for ~1 second */
         wait_for_ctrl_irq (ctrl);
@@ -340,7 +340,7 @@ static int board_added(struct slot *p_slot)
                 pci_fixup_device(pci_fixup_final, ctrl->pci_dev);
         if (PWR_LED(ctrl->ctrlcap)) {
                 /* Wait for exclusive access to hardware */
-                mutex_lock(&ctrl->crit_sect);
+                mutex_lock(&ctrl->ctrl_lock);
 
                 p_slot->hpc_ops->green_led_on(p_slot);
   
@@ -348,7 +348,7 @@ static int board_added(struct slot *p_slot)
                 wait_for_ctrl_irq (ctrl);
         
                 /* Done with exclusive hardware access */
-                mutex_unlock(&ctrl->crit_sect);
+                mutex_unlock(&ctrl->ctrl_lock);
         }
         return 0;
 
@@ -380,14 +380,14 @@ static int remove_board(struct slot *p_slot)
         dbg("In %s, hp_slot = %d\n", __FUNCTION__, hp_slot);
 
         /* Wait for exclusive access to hardware */
-        mutex_lock(&ctrl->crit_sect);
+        mutex_lock(&ctrl->ctrl_lock);
 
         if (POWER_CTRL(ctrl->ctrlcap)) {
                 /* power off slot */
                 rc = p_slot->hpc_ops->power_off_slot(p_slot);
                 if (rc) {
                         err("%s: Issue of Slot Disable command failed\n", __FUNCTION__);
-                        mutex_unlock(&ctrl->crit_sect);
+                        mutex_unlock(&ctrl->ctrl_lock);
                         return rc;
                 }
                 /* Wait for the command to complete */
@@ -403,7 +403,7 @@ static int remove_board(struct slot *p_slot)
         }
 
         /* Done with exclusive hardware access */
-        mutex_unlock(&ctrl->crit_sect);
+        mutex_unlock(&ctrl->ctrl_lock);
 
         return 0;
 }
@@ -450,7 +450,7 @@ static void pciehp_pushbutton_thread(unsigned long slot)
 
                 if (pciehp_enable_slot(p_slot) && PWR_LED(p_slot->ctrl->ctrlcap)) {
                         /* Wait for exclusive access to hardware */
-                        mutex_lock(&p_slot->ctrl->crit_sect);
+                        mutex_lock(&p_slot->ctrl->ctrl_lock);
 
                         p_slot->hpc_ops->green_led_off(p_slot);
 
@@ -458,7 +458,7 @@ static void pciehp_pushbutton_thread(unsigned long slot)
                         wait_for_ctrl_irq (p_slot->ctrl);
 
                         /* Done with exclusive hardware access */
-                        mutex_unlock(&p_slot->ctrl->crit_sect);
+                        mutex_unlock(&p_slot->ctrl->ctrl_lock);
                 }
                 p_slot->state = STATIC_STATE;
         }
@@ -500,7 +500,7 @@ static void pciehp_surprise_rm_thread(unsigned long slot)
 
                 if (pciehp_enable_slot(p_slot) && PWR_LED(p_slot->ctrl->ctrlcap)) {
                         /* Wait for exclusive access to hardware */
-                        mutex_lock(&p_slot->ctrl->crit_sect);
+                        mutex_lock(&p_slot->ctrl->ctrl_lock);
 
                         p_slot->hpc_ops->green_led_off(p_slot);
 
@@ -508,7 +508,7 @@ static void pciehp_surprise_rm_thread(unsigned long slot)
                         wait_for_ctrl_irq (p_slot->ctrl);
 
                         /* Done with exclusive hardware access */
-                        mutex_unlock(&p_slot->ctrl->crit_sect);
+                        mutex_unlock(&p_slot->ctrl->ctrl_lock);
                 }
                 p_slot->state = STATIC_STATE;
         }
@@ -621,7 +621,7 @@ static void interrupt_event_handler(struct controller *ctrl)
                                         switch (p_slot->state) {
                                         case BLINKINGOFF_STATE:
                                                 /* Wait for exclusive access to hardware */
-                                                mutex_lock(&ctrl->crit_sect);
+                                                mutex_lock(&ctrl->ctrl_lock);
                                                 
                                                 if (PWR_LED(ctrl->ctrlcap)) {
                                                         p_slot->hpc_ops->green_led_on(p_slot);
@@ -635,11 +635,11 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                         wait_for_ctrl_irq (ctrl);
                                                 }
                                                 /* Done with exclusive hardware access */
-                                                mutex_unlock(&ctrl->crit_sect);
+                                                mutex_unlock(&ctrl->ctrl_lock);
                                                 break;
                                         case BLINKINGON_STATE:
                                                 /* Wait for exclusive access to hardware */
-                                                mutex_lock(&ctrl->crit_sect);
+                                                mutex_lock(&ctrl->ctrl_lock);
 
                                                 if (PWR_LED(ctrl->ctrlcap)) {
                                                         p_slot->hpc_ops->green_led_off(p_slot);
@@ -652,7 +652,7 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                         wait_for_ctrl_irq (ctrl);
                                                 }
                                                 /* Done with exclusive hardware access */
-                                                mutex_unlock(&ctrl->crit_sect);
+                                                mutex_unlock(&ctrl->ctrl_lock);
 
                                                 break;
                                         default:
@@ -681,7 +681,7 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                 }
 
                                                 /* Wait for exclusive access to hardware */
-                                                mutex_lock(&ctrl->crit_sect);
+                                                mutex_lock(&ctrl->ctrl_lock);
 
                                                 /* blink green LED and turn off amber */
                                                 if (PWR_LED(ctrl->ctrlcap)) {
@@ -698,7 +698,7 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                 }
 
                                                 /* Done with exclusive hardware access */
-                                                mutex_unlock(&ctrl->crit_sect);
+                                                mutex_unlock(&ctrl->ctrl_lock);
 
                                                 init_timer(&p_slot->task_event);
                                                 p_slot->task_event.expires = jiffies + 5 * HZ;   /* 5 second delay */
@@ -713,7 +713,7 @@ static void interrupt_event_handler(struct controller *ctrl)
                                         if (POWER_CTRL(ctrl->ctrlcap)) {
                                                 dbg("power fault\n");
                                                 /* Wait for exclusive access to hardware */
-                                                mutex_lock(&ctrl->crit_sect);
+                                                mutex_lock(&ctrl->ctrl_lock);
 
                                                 if (ATTN_LED(ctrl->ctrlcap)) {
                                                         p_slot->hpc_ops->set_attention_status(p_slot, 1);
@@ -726,7 +726,7 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                 }
 
                                                 /* Done with exclusive hardware access */
-                                                mutex_unlock(&ctrl->crit_sect);
+                                                mutex_unlock(&ctrl->ctrl_lock);
                                         }
                                 }
                                 /***********SURPRISE REMOVAL********************/
@@ -789,7 +789,6 @@ int pciehp_enable_slot(struct slot *p_slot)
                         return -EINVAL;
                 }
         }
-        mutex_unlock(&p_slot->ctrl->crit_sect);
 
         p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
 
@@ -801,6 +800,7 @@ int pciehp_enable_slot(struct slot *p_slot)
         if (p_slot)
                 update_slot_info(p_slot);
 
+        mutex_unlock(&p_slot->ctrl->crit_sect);
         return rc;
 }
 
@@ -846,10 +846,10 @@ int pciehp_disable_slot(struct slot *p_slot)
                 }
         }
 
-        mutex_unlock(&p_slot->ctrl->crit_sect);
-
         ret = remove_board(p_slot);
         update_slot_info(p_slot);
+
+        mutex_unlock(&p_slot->ctrl->crit_sect);
         return ret;
 }
 
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 703a64a39fe8..1c551c697c35 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -1402,6 +1402,8 @@ int pcie_init(struct controller * ctrl, struct pcie_device *dev)
                 pdev->subsystem_vendor, pdev->subsystem_device);
 
         mutex_init(&ctrl->crit_sect);
+        mutex_init(&ctrl->ctrl_lock);
+
         /* setup wait queue */
         init_waitqueue_head(&ctrl->queue);