ACPI / APEI: Fix the returned value in erst_dbg_read

If the persistent store is empty initially, the function 'erst_dbg_read'
returns a nonzero value. The better way is to return a zero indicating the
read operation reaches EOF.

Tested on two different servers.

Signed-off-by: Adrian Huang <adrian.huang@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/apei/erst-dbg.c b/drivers/acpi/apei/erst-dbg.c
index 903549df809bf1b02cc95df234dd7442cd3fb3ee..04ab5c9d3cedc16ac5250ee70b610829216d6117 100644 (file)
--- a/drivers/acpi/apei/erst-dbg.c
+++ b/drivers/acpi/apei/erst-dbg.c
@@ -111,8 +111,17 @@ retry_next:
        if (rc)
                goto out;
        /* no more record */
-       if (id == APEI_ERST_INVALID_RECORD_ID)
+       if (id == APEI_ERST_INVALID_RECORD_ID) {
+               /*
+                * If the persistent store is empty initially, the function
+                * 'erst_read' below will return "-ENOENT" value. This causes
+                * 'retry_next' label is entered again. The returned value
+                * should be zero indicating the read operation is EOF.
+                */
+               len = 0;
+
                goto out;
+       }
 retry:
        rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
        /* The record may be cleared by others, try read next record */