Define a cleanup helper for use with __free to release the acpi table when
the pointer goes out of scope. Also, introduce the helper
acpi_get_table_pointer() to simplify a commonly used pattern involving
acpi_get_table().

These are first used in a subsequent commit.

Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
---
Changes since v5:
Rename helper to acpi_get_table_pointer
---
 include/linux/acpi.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index a9dbacabdf89..ac8797f95236 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -8,6 +8,7 @@
 #ifndef _LINUX_ACPI_H
 #define _LINUX_ACPI_H
 
+#include <linux/cleanup.h>
 #include <linux/errno.h>
 #include <linux/ioport.h>	/* for struct resource */
 #include <linux/resource_ext.h>
@@ -221,6 +222,17 @@ void acpi_reserve_initial_tables (void);
 void acpi_table_init_complete (void);
 int acpi_table_init (void);
 
+static inline struct acpi_table_header *acpi_get_table_pointer(char *signature, u32 instance)
+{
+	struct acpi_table_header *table;
+	int status = acpi_get_table(signature, instance, &table);
+
+	if (ACPI_FAILURE(status))
+		return ERR_PTR(-ENOENT);
+	return table;
+}
+DEFINE_FREE(acpi_put_table, struct acpi_table_header *, if (!IS_ERR_OR_NULL(_T)) acpi_put_table(_T))
+
 int acpi_table_parse(char *id, acpi_tbl_table_handler handler);
 int __init_or_acpilib acpi_table_parse_entries(char *id,
 		unsigned long table_size, int entry_id,
-- 
2.43.0