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Commit e56f5617 authored by Bob Moore's avatar Bob Moore Committed by Len Brown
Browse files

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: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarLin Ming <ming.m.lin@intel.com>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 237a9276

drivers/acpi/tables/tbinstal.c

+42 −7
Original line number Diff line number Diff line
@@ -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;



		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: