Since we serialize the present/eject work items now, we don't need the
semaphore any more.

This is suggested by Michael Kelley.

Signed-off-by: Dexuan Cui <de...@microsoft.com>
Cc: Vitaly Kuznetsov <vkuzn...@redhat.com>
Cc: Jack Morgenstein <ja...@mellanox.com>
Cc: sta...@vger.kernel.org
Cc: Stephen Hemminger <sthem...@microsoft.com>
Cc: K. Y. Srinivasan <k...@microsoft.com>
Cc: Michael Kelley (EOSG) <michael.h.kel...@microsoft.com>
---
 drivers/pci/host/pci-hyperv.c | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index aaee41faf55f..3a385212f666 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -447,7 +447,6 @@ struct hv_pcibus_device {
        spinlock_t device_list_lock;    /* Protect lists below */
        void __iomem *cfg_addr;
 
-       struct semaphore enum_sem;
        struct list_head resources_for_children;
 
        struct list_head children;
@@ -1592,12 +1591,8 @@ static struct hv_pci_dev *get_pcichild_wslot(struct 
hv_pcibus_device *hbus,
  * It must also treat the omission of a previously observed device as
  * notification that the device no longer exists.
  *
- * Note that this function is a work item, and it may not be
- * invoked in the order that it was queued.  Back to back
- * updates of the list of present devices may involve queuing
- * multiple work items, and this one may run before ones that
- * were sent later. As such, this function only does something
- * if is the last one in the queue.
+ * Note that this function is serialized with hv_eject_device_work(),
+ * because both are pushed to the ordered workqueue hbus->wq.
  */
 static void pci_devices_present_work(struct work_struct *work)
 {
@@ -1618,11 +1613,6 @@ static void pci_devices_present_work(struct work_struct 
*work)
 
        INIT_LIST_HEAD(&removed);
 
-       if (down_interruptible(&hbus->enum_sem)) {
-               put_hvpcibus(hbus);
-               return;
-       }
-
        /* Pull this off the queue and process it if it was the last one. */
        spin_lock_irqsave(&hbus->device_list_lock, flags);
        while (!list_empty(&hbus->dr_list)) {
@@ -1639,7 +1629,6 @@ static void pci_devices_present_work(struct work_struct 
*work)
        spin_unlock_irqrestore(&hbus->device_list_lock, flags);
 
        if (!dr) {
-               up(&hbus->enum_sem);
                put_hvpcibus(hbus);
                return;
        }
@@ -1726,7 +1715,6 @@ static void pci_devices_present_work(struct work_struct 
*work)
                break;
        }
 
-       up(&hbus->enum_sem);
        put_hvpcibus(hbus);
        kfree(dr);
 }
@@ -2460,7 +2448,6 @@ static int hv_pci_probe(struct hv_device *hdev,
        spin_lock_init(&hbus->config_lock);
        spin_lock_init(&hbus->device_list_lock);
        spin_lock_init(&hbus->retarget_msi_interrupt_lock);
-       sema_init(&hbus->enum_sem, 1);
        init_completion(&hbus->remove_event);
        hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0,
                                           hbus->sysdata.domain);
-- 
2.7.4

Reply via email to