ACPICA: Allow same ACPI table to be loaded/unloaded more than once

Without this change, a table cannot be loaded again once it has
been loaded/unloaded one time. The current mechanism does not
unregister a table upon an unload. During a load, if the same
table is found, this no longer returns an exception.

http://www.acpica.org/bugzilla/show_bug.cgi?id=722

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Bob Moore 2008-07-04 10:48:43 +08:00 committed by Len Brown
parent 237a927682
commit e56f561736

View File

@ -145,6 +145,8 @@ acpi_tb_add_table(struct acpi_table_desc *table_desc, u32 *table_index)
}
}
/* Check for a table match on the entire table length */
length = ACPI_MIN(table_desc->length,
acpi_gbl_root_table_list.tables[i].length);
if (ACPI_MEMCMP(table_desc->pointer,
@ -153,17 +155,49 @@ acpi_tb_add_table(struct acpi_table_desc *table_desc, u32 *table_index)
continue;
}
/* Table is already registered */
/*
* Note: the current mechanism does not unregister a table if it is
* dynamically unloaded. The related namespace entries are deleted,
* but the table remains in the root table list.
*
* The assumption here is that the number of different tables that
* will be loaded is actually small, and there is minimal overhead
* in just keeping the table in case it is needed again.
*
* If this assumption changes in the future (perhaps on large
* machines with many table load/unload operations), tables will
* need to be unregistered when they are unloaded, and slots in the
* root table list should be reused when empty.
*/
/*
* Table is already registered.
* We can delete the table that was passed as a parameter.
*/
acpi_tb_delete_table(table_desc);
*table_index = i;
status = AE_ALREADY_EXISTS;
goto release;
if (acpi_gbl_root_table_list.tables[i].
flags & ACPI_TABLE_IS_LOADED) {
/* Table is still loaded, this is an error */
status = AE_ALREADY_EXISTS;
goto release;
} else {
/* Table was unloaded, allow it to be reloaded */
table_desc->pointer =
acpi_gbl_root_table_list.tables[i].pointer;
table_desc->address =
acpi_gbl_root_table_list.tables[i].address;
status = AE_OK;
goto print_header;
}
}
/*
* Add the table to the global table list
*/
/* Add the table to the global root table list */
status = acpi_tb_store_table(table_desc->address, table_desc->pointer,
table_desc->length, table_desc->flags,
table_index);
@ -171,6 +205,7 @@ acpi_tb_add_table(struct acpi_table_desc *table_desc, u32 *table_index)
goto release;
}
print_header:
acpi_tb_print_table_header(table_desc->address, table_desc->pointer);
release: