[PATCH] shpchp: Create shpchpd at controller probe time

The workqueue thread of shpchp driver should be created only when SHPC
based hotplug slots are detected on the system.

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

2 files changed, 19 insertions, 8 deletions

diff --git a/drivers/pci/hotplug/shpchp_core.c b/drivers/pci/hotplug/shpchp_core.c
index 3be4d492ccc2..a14e7de19846 100644
--- a/drivers/pci/hotplug/shpchp_core.c
+++ b/drivers/pci/hotplug/shpchp_core.c
@@ -491,16 +491,9 @@ static int __init shpcd_init(void)
         shpchp_poll_mode = 1;
 #endif
 
-        shpchp_wq = create_singlethread_workqueue("shpchpd");
-        if (!shpchp_wq)
-                return -ENOMEM;
-
         retval = pci_register_driver(&shpc_driver);
         dbg("%s: pci_register_driver = %d\n", __FUNCTION__, retval);
         info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
-        if (retval) {
-                destroy_workqueue(shpchp_wq);
-        }
         return retval;
 }
 
@@ -508,7 +501,6 @@ static void __exit shpcd_cleanup(void)
 {
         dbg("unload_shpchpd()\n");
         pci_unregister_driver(&shpc_driver);
-        destroy_workqueue(shpchp_wq);
         info(DRIVER_DESC " version: " DRIVER_VERSION " unloaded\n");
 }
 
diff --git a/drivers/pci/hotplug/shpchp_hpc.c b/drivers/pci/hotplug/shpchp_hpc.c
index 8b63f772a6f2..5e8f589d0b64 100644
--- a/drivers/pci/hotplug/shpchp_hpc.c
+++ b/drivers/pci/hotplug/shpchp_hpc.c
@@ -216,6 +216,8 @@ static struct php_ctlr_state_s *php_ctlr_list_head;	/* HPC state linked list */
 static int ctlr_seq_num = 0;    /* Controller sequenc # */
 static spinlock_t list_lock;
 
+static atomic_t shpchp_num_controllers = ATOMIC_INIT(0);
+
 static irqreturn_t shpc_isr(int IRQ, void *dev_id, struct pt_regs *regs);
 
 static void start_int_poll_timer(struct php_ctlr_state_s *php_ctlr, int seconds);
@@ -866,6 +868,13 @@ static void hpc_release_ctlr(struct controller *ctrl)
 
         kfree(php_ctlr);
 
+        /*
+         * If this is the last controller to be released, destroy the
+         * shpchpd work queue
+         */
+        if (atomic_dec_and_test(&shpchp_num_controllers))
+                destroy_workqueue(shpchp_wq);
+
 DBG_LEAVE_ROUTINE
                           
 }
@@ -1461,6 +1470,16 @@ int shpc_init(struct controller * ctrl, struct pci_dev * pdev)
         ctlr_seq_num++;
 
         /*
+         * If this is the first controller to be initialized,
+         * initialize the shpchpd work queue
+         */
+        if (atomic_add_return(1, &shpchp_num_controllers) == 1) {
+                shpchp_wq = create_singlethread_workqueue("shpchpd");
+                if (!shpchp_wq)
+                        return -ENOMEM;
+        }
+
+        /*
          * Unmask all event interrupts of all slots
          */
         for (hp_slot = 0; hp_slot < php_ctlr->num_slots; hp_slot++) {