[PATCH 1/1] ACPI/APEI: Fix the returned value in erst_dbg_read

[PATCH 1/1] ACPI/APEI: Fix the returned value in erst_dbg_read

[Adrian Huang]

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>
---
 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 903549d..04ab5c9 100644
--- 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 */
-- 
1.7.10.4

Re: [PATCH 1/1] ACPI/APEI: Fix the returned value in erst_dbg_read

[Rafael J. Wysocki]

On Friday, December 14, 2012 04:08:34 PM Adrian Huang wrote:
> 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.

I'm queuing this up for submission as v3.8 material.

Thanks,
Rafael


> Signed-off-by: Adrian Huang <adrian.huang@hp.com>
> ---
>  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 903549d..04ab5c9 100644
> --- 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 */
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.