PCI/ACPI: Remove unnecessary osc_lock

9778c14b4ca2 ("ACPI/PCI: Fix possible race condition on _OSC evaluation")
added locking around _OSC calls to protect the acpi_osc_data_list that
stored the results.

63f10f0f6df4 ("PCI/ACPI: move _OSC code to pci_root.c") moved the results
from acpi_osc_data_list to the struct acpi_pci_root, where it no longer
needs locking, but did not remove the lock.

Remove the unnecessary locking around _OSC calls.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7d5a4bd..ea08b32 100644 (file)
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -56,8 +56,6 @@ static struct acpi_scan_handler pci_root_handler = {
        },
 };
 
-static DEFINE_MUTEX(osc_lock);
-
 /**
  * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
  * @handle:  the ACPI CA node in question.
@@ -223,12 +221,7 @@ static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
 
 static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 {
-       acpi_status status;
-
-       mutex_lock(&osc_lock);
-       status = acpi_pci_query_osc(root, flags, NULL);
-       mutex_unlock(&osc_lock);
-       return status;
+       return acpi_pci_query_osc(root, flags, NULL);
 }
 
 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
@@ -356,7 +349,7 @@ EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
 static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
 {
        struct acpi_pci_root *root;
-       acpi_status status = AE_OK;
+       acpi_status status;
        u32 ctrl, capbuf[3];
 
        if (!mask)
@@ -370,18 +363,16 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 r
        if (!root)
                return AE_NOT_EXIST;
 
-       mutex_lock(&osc_lock);
-
        *mask = ctrl | root->osc_control_set;
        /* No need to evaluate _OSC if the control was already granted. */
        if ((root->osc_control_set & ctrl) == ctrl)
-               goto out;
+               return AE_OK;
 
        /* Need to check the available controls bits before requesting them. */
        while (*mask) {
                status = acpi_pci_query_osc(root, root->osc_support_set, mask);
                if (ACPI_FAILURE(status))
-                       goto out;
+                       return status;
                if (ctrl == *mask)
                        break;
                decode_osc_control(root, "platform does not support",
@@ -392,19 +383,18 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 r
        if ((ctrl & req) != req) {
                decode_osc_control(root, "not requesting control; platform does not support",
                                   req & ~(ctrl));
-               status = AE_SUPPORT;
-               goto out;
+               return AE_SUPPORT;
        }
 
        capbuf[OSC_QUERY_DWORD] = 0;
        capbuf[OSC_SUPPORT_DWORD] = root->osc_support_set;
        capbuf[OSC_CONTROL_DWORD] = ctrl;
        status = acpi_pci_run_osc(handle, capbuf, mask);
-       if (ACPI_SUCCESS(status))
-               root->osc_control_set = *mask;
-out:
-       mutex_unlock(&osc_lock);
-       return status;
+       if (ACPI_FAILURE(status))
+               return status;
+
+       root->osc_control_set = *mask;
+       return AE_OK;
 }
 
 static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,