Commit 866e61fc authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

PCI/ACPI: Remove unnecessary osc_lock 



9778c14b ("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.

63f10f0f ("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: default avatarBjorn Helgaas <bhelgaas@google.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 1423de71

drivers/acpi/pci_root.c

+10 −20
Original line number Diff line number Diff line
@@ -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);

	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,