ACPI, APEI, Add ERST record ID cache
APEI ERST firmware interface and implementation has no multiple users
in mind. For example, if there is four records in storage with ID: 1,
2, 3 and 4, if two ERST readers enumerate the records via
GET_NEXT_RECORD_ID as follow,
reader 1 reader 2
1
2
3
4
-1
-1
where -1 signals there is no more record ID.
Reader 1 has no chance to check record 2 and 4, while reader 2 has no
chance to check record 1 and 3. And any other GET_NEXT_RECORD_ID will
return -1, that is, other readers will has no chance to check any
record even they are not cleared by anyone.
This makes raw GET_NEXT_RECORD_ID not suitable for used by multiple
users.
To solve the issue, an in-memory ERST record ID cache is designed and
implemented. When enumerating record ID, the ID returned by
GET_NEXT_RECORD_ID is added into cache in addition to be returned to
caller. So other readers can check the cache to get all record ID
available.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/include/acpi/apei.h b/include/acpi/apei.h
index c4dbb13..e67b523 100644
--- a/include/acpi/apei.h
+++ b/include/acpi/apei.h
@@ -30,10 +30,11 @@
int erst_write(const struct cper_record_header *record);
ssize_t erst_get_record_count(void);
-int erst_get_next_record_id(u64 *record_id);
+int erst_get_record_id_begin(int *pos);
+int erst_get_record_id_next(int *pos, u64 *record_id);
+void erst_get_record_id_end(void);
ssize_t erst_read(u64 record_id, struct cper_record_header *record,
size_t buflen);
-ssize_t erst_read_next(struct cper_record_header *record, size_t buflen);
int erst_clear(u64 record_id);
#endif