[PATCH v4 3/3] mm: memory-failure: Enhance comments for return value of memory_failure()

[Shuai Xue <xueshuai@linux.alibaba.com>]

The comments for the return value of memory_failure are not complete,
supplement the comments.

Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Tested-by: Tony Luck <tony.luck@intel.com>
---
 mm/memory-failure.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b037952565be..8649849bcdb4 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2216,9 +2216,13 @@ static void kill_procs_now(struct page *p, unsigned long pfn, int flags,
  * Must run in process context (e.g. a work queue) with interrupts
  * enabled and no spinlocks held.
  *
- * Return: 0 for successfully handled the memory error,
- *         -EOPNOTSUPP for hwpoison_filter() filtered the error event,
- *         < 0(except -EOPNOTSUPP) on failure.
+ * Return:
+ *   0             - success,
+ *   -ENXIO        - memory not managed by the kernel
+ *   -EOPNOTSUPP   - hwpoison_filter() filtered the error event,
+ *   -EHWPOISON    - the page was already poisoned, potentially
+ *                   kill process,
+ *   other negative values - failure.
  */
 int memory_failure(unsigned long pfn, int flags)
 {
-- 
2.39.3