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ACPI/PCI: Fix possible race condition on _OSC evaluation 

Fix possible race condition on _OSC evaluation.

Current _OSC evaluation code has possible race condition because it
maniputes osc_data linked list or its contents without any lock
mechanism.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Taku Izumi 2008-10-17 13:48:36 +09:00 committed by Jesse Barnes
parent 2515ddc6db
commit 9778c14b4c
1 changed files with 20 additions and 8 deletions
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28
drivers/pci/pci-acpi.c
View File

@ -35,6 +35,8 @@ struct acpi_osc_args {
u32 query_result; u32 query_result;
}; };
static DEFINE_MUTEX(pci_acpi_lock);
static struct acpi_osc_data *acpi_get_osc_data(acpi_handle handle) static struct acpi_osc_data *acpi_get_osc_data(acpi_handle handle)
{ {
struct acpi_osc_data *data; struct acpi_osc_data *data;
@ -131,10 +133,12 @@ static acpi_status acpi_query_osc(acpi_handle handle,
if (ACPI_FAILURE(status)) if (ACPI_FAILURE(status))
return status; return status;
mutex_lock(&pci_acpi_lock);
osc_data = acpi_get_osc_data(handle); osc_data = acpi_get_osc_data(handle);
if (!osc_data) { if (!osc_data) {
printk(KERN_ERR "acpi osc data array is full\n"); printk(KERN_ERR "acpi osc data array is full\n");
return AE_ERROR; status = AE_ERROR;
goto out;
} }
/* do _OSC query for all possible controls */ /* do _OSC query for all possible controls */
@ -149,7 +153,8 @@ static acpi_status acpi_query_osc(acpi_handle handle,
osc_data->query_result = osc_args.query_result; osc_data->query_result = osc_args.query_result;
osc_data->is_queried = 1; osc_data->is_queried = 1;
} }
out:
mutex_unlock(&pci_acpi_lock);
return status; return status;
} }
@ -190,19 +195,25 @@ acpi_status pci_osc_control_set(acpi_handle handle, u32 flags)
if (ACPI_FAILURE(status)) if (ACPI_FAILURE(status))
return status; return status;
mutex_lock(&pci_acpi_lock);
osc_data = acpi_get_osc_data(handle); osc_data = acpi_get_osc_data(handle);
if (!osc_data) { if (!osc_data) {
printk(KERN_ERR "acpi osc data array is full\n"); printk(KERN_ERR "acpi osc data array is full\n");
return AE_ERROR; status = AE_ERROR;
goto out;
} }
ctrlset = (flags & OSC_CONTROL_MASKS); ctrlset = (flags & OSC_CONTROL_MASKS);
if (!ctrlset) if (!ctrlset) {
return AE_TYPE; status = AE_TYPE;
goto out;
}
if (osc_data->is_queried && if (osc_data->is_queried &&
((osc_data->query_result & ctrlset) != ctrlset)) ((osc_data->query_result & ctrlset) != ctrlset)) {
return AE_SUPPORT; status = AE_SUPPORT;
goto out;
}
control_set = osc_data->control_set | ctrlset; control_set = osc_data->control_set | ctrlset;
osc_args.capbuf[OSC_QUERY_TYPE] = 0; osc_args.capbuf[OSC_QUERY_TYPE] = 0;
@ -211,7 +222,8 @@ acpi_status pci_osc_control_set(acpi_handle handle, u32 flags)
status = acpi_run_osc(handle, &osc_args); status = acpi_run_osc(handle, &osc_args);
if (ACPI_SUCCESS(status)) if (ACPI_SUCCESS(status))
osc_data->control_set = control_set; osc_data->control_set = control_set;
out:
mutex_unlock(&pci_acpi_lock);
return status; return status;
} }
EXPORT_SYMBOL(pci_osc_control_set); EXPORT_SYMBOL(pci_osc_control_set);