From 6780aa683d4d83ed887dd07b7987947d339d76f1 Mon Sep 17 00:00:00 2001 From: Adrian Huang Date: Sat, 15 Dec 2012 00:30:07 +0100 Subject: [PATCH] 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 Signed-off-by: Rafael J. Wysocki --- drivers/acpi/apei/erst-dbg.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/apei/erst-dbg.c b/drivers/acpi/apei/erst-dbg.c index 903549df809b..04ab5c9d3ced 100644 --- a/drivers/acpi/apei/erst-dbg.c +++ b/drivers/acpi/apei/erst-dbg.c @@ -111,8 +111,17 @@ static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf, 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 */