ACPI: PCI: simplify buffer management for evaluating _PRT

Previously, acpi_pci_irq_add_prt() did all its own buffer management.
But now that we have ACPI_ALLOCATE_BUFFER, we no longer need to do
that management.  And we don't have to call acpi_get_irq_routing_table()
twice (once to learn the size of the buffer needed, and again to
actually get the table).

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 6c04060..6a9f3dd 100644 (file)
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -243,55 +243,29 @@ acpi_pci_irq_del_entry(int segment, int bus, struct acpi_prt_entry *entry)
 
 int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
 {
-       acpi_status status = AE_OK;
-       char *pathname = NULL;
-       struct acpi_buffer buffer = { 0, NULL };
-       struct acpi_pci_routing_table *prt = NULL;
-       struct acpi_pci_routing_table *entry = NULL;
+       acpi_status status;
+       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+       struct acpi_pci_routing_table *entry;
        static int first_time = 1;
 
-
-       pathname = kzalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);
-       if (!pathname)
-               return -ENOMEM;
-
        if (first_time) {
                acpi_prt.count = 0;
                INIT_LIST_HEAD(&acpi_prt.entries);
                first_time = 0;
        }
 
-       /* 
-        * NOTE: We're given a 'handle' to the _PRT object's parent device
-        *       (either a PCI root bridge or PCI-PCI bridge).
-        */
-
-       buffer.length = ACPI_PATHNAME_MAX;
-       buffer.pointer = pathname;
-       acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
+       /* 'handle' is the _PRT's parent (root bridge or PCI-PCI bridge) */
+       status = acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
+       if (ACPI_FAILURE(status))
+               return -ENODEV;
 
        printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
-              pathname);
+              (char *) buffer.pointer);
 
-       /* 
-        * Evaluate this _PRT and add its entries to our global list (acpi_prt).
-        */
+       kfree(buffer.pointer);
 
-       buffer.length = 0;
+       buffer.length = ACPI_ALLOCATE_BUFFER;
        buffer.pointer = NULL;
-       kfree(pathname);
-       status = acpi_get_irq_routing_table(handle, &buffer);
-       if (status != AE_BUFFER_OVERFLOW) {
-               ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
-                               acpi_format_exception(status)));
-               return -ENODEV;
-       }
-
-       prt = kzalloc(buffer.length, GFP_KERNEL);
-       if (!prt) {
-               return -ENOMEM;
-       }
-       buffer.pointer = prt;
 
        status = acpi_get_irq_routing_table(handle, &buffer);
        if (ACPI_FAILURE(status)) {
@@ -301,16 +275,14 @@ int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
                return -ENODEV;
        }
 
-       entry = prt;
-
+       entry = buffer.pointer;
        while (entry && (entry->length > 0)) {
                acpi_pci_irq_add_entry(handle, segment, bus, entry);
                entry = (struct acpi_pci_routing_table *)
                    ((unsigned long)entry + entry->length);
        }
 
-       kfree(prt);
-
+       kfree(buffer.pointer);
        return 0;
 }