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Code Issues Releases Wiki Activity

PCI/ACPI: Remove unnecessary osc_lock

Browse source 
9778c14b4c ("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.

63f10f0f6d ("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>
This commit is contained in:
Bjorn Helgaas 2020-06-02 17:27:33 -05:00
parent 1423de718e
commit 866e61fc40
1 changed files with 10 additions and 20 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

30
drivers/acpi/pci_root.c
View file

@ -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,