ACPI / OSL: Clean up initrd table override code

This patch cleans up the initrd table override code by merging
redundant logics and re-ordering code blocks.

No functional changes.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 67da6fb..a8c417c 100644 (file)
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -602,6 +602,14 @@ acpi_os_predefined_override(const struct acpi_predefined_names *init_val,
        return AE_OK;
 }
 
+static void acpi_table_taint(struct acpi_table_header *table)
+{
+       pr_warn(PREFIX
+               "Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
+               table->signature, table->oem_table_id);
+       add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
+}
+
 #ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
 #include <linux/earlycpio.h>
 #include <linux/memblock.h>
@@ -746,96 +754,78 @@ void __init acpi_initrd_override(void *data, size_t size)
                }
        }
 }
-#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
-
-static void acpi_table_taint(struct acpi_table_header *table)
-{
-       pr_warn(PREFIX
-               "Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
-               table->signature, table->oem_table_id);
-       add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
-}
-
-
-acpi_status
-acpi_os_table_override(struct acpi_table_header * existing_table,
-                      struct acpi_table_header ** new_table)
-{
-       if (!existing_table || !new_table)
-               return AE_BAD_PARAMETER;
-
-       *new_table = NULL;
-
-#ifdef CONFIG_ACPI_CUSTOM_DSDT
-       if (strncmp(existing_table->signature, "DSDT", 4) == 0)
-               *new_table = (struct acpi_table_header *)AmlCode;
-#endif
-       if (*new_table != NULL)
-               acpi_table_taint(existing_table);
-       return AE_OK;
-}
 
 acpi_status
 acpi_os_physical_table_override(struct acpi_table_header *existing_table,
-                               acpi_physical_address *address,
-                               u32 *table_length)
+                               acpi_physical_address *address, u32 *length)
 {
-#ifndef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
-       *table_length = 0;
-       *address = 0;
-       return AE_OK;
-#else
        int table_offset = 0;
        struct acpi_table_header *table;
+       u32 table_length;
 
-       *table_length = 0;
+       *length = 0;
        *address = 0;
-
        if (!acpi_tables_addr)
                return AE_OK;
 
-       do {
-               if (table_offset + ACPI_HEADER_SIZE > all_tables_size) {
-                       WARN_ON(1);
-                       return AE_OK;
-               }
-
+       while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
                table = acpi_os_map_memory(acpi_tables_addr + table_offset,
                                           ACPI_HEADER_SIZE);
-
                if (table_offset + table->length > all_tables_size) {
                        acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
                        WARN_ON(1);
                        return AE_OK;
                }
 
-               table_offset += table->length;
+               table_length = table->length;
 
-               if (memcmp(existing_table->signature, table->signature, 4)) {
-                       acpi_os_unmap_memory(table,
-                                    ACPI_HEADER_SIZE);
-                       continue;
-               }
-
-               /* Only override tables with matching oem id */
-               if (memcmp(table->oem_table_id, existing_table->oem_table_id,
+               /* Only override tables matched */
+               if (memcmp(existing_table->signature, table->signature, 4) ||
+                   memcmp(table->oem_table_id, existing_table->oem_table_id,
                           ACPI_OEM_TABLE_ID_SIZE)) {
-                       acpi_os_unmap_memory(table,
-                                    ACPI_HEADER_SIZE);
-                       continue;
+                       acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+                       goto next_table;
                }
 
-               table_offset -= table->length;
-               *table_length = table->length;
-               acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+               *length = table_length;
                *address = acpi_tables_addr + table_offset;
+               acpi_table_taint(existing_table);
+               acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
                break;
-       } while (table_offset + ACPI_HEADER_SIZE < all_tables_size);
 
-       if (*address != 0)
-               acpi_table_taint(existing_table);
+next_table:
+               table_offset += table_length;
+       }
        return AE_OK;
+}
+#else
+acpi_status
+acpi_os_physical_table_override(struct acpi_table_header *existing_table,
+                               acpi_physical_address *address,
+                               u32 *table_length)
+{
+       *table_length = 0;
+       *address = 0;
+       return AE_OK;
+}
+#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
+
+acpi_status
+acpi_os_table_override(struct acpi_table_header *existing_table,
+                      struct acpi_table_header **new_table)
+{
+       if (!existing_table || !new_table)
+               return AE_BAD_PARAMETER;
+
+       *new_table = NULL;
+
+#ifdef CONFIG_ACPI_CUSTOM_DSDT
+       if (strncmp(existing_table->signature, "DSDT", 4) == 0)
+               *new_table = (struct acpi_table_header *)AmlCode;
 #endif
+       if (*new_table != NULL)
+               acpi_table_taint(existing_table);
+       return AE_OK;
 }
 
 static irqreturn_t acpi_irq(int irq, void *dev_id)