[PATCH] swapfile : export more return values for swap_duplicate()

[Huang Shijie <shijie8@gmail.com>]

Exporting more return values for swap_duplicate() is useful for
try_to_unmap(). It could check the swap entry more carefully which
is helpful for the system stability.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
---
 mm/memory.c   |    3 ++-
 mm/swapfile.c |    2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 72fb5f3..72d1d1c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -586,7 +586,8 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		if (!pte_file(pte)) {
 			swp_entry_t entry = pte_to_swp_entry(pte);
 
-			if (swap_duplicate(entry) < 0)
+			/* add_swap_count_continuation() failed ? */
+			if (swap_duplicate(entry) == -ENOMEM)
 				return entry.val;
 
 			/* make sure dst_mm is on swapoff's mmlist. */
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 6c0585b..a2720d0 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2161,7 +2161,7 @@ int swap_duplicate(swp_entry_t entry)
 {
 	int err = 0;
 
-	while (!err && __swap_duplicate(entry, 1) == -ENOMEM)
+	while (!err && (err =  __swap_duplicate(entry, 1)) == -ENOMEM)
 		err = add_swap_count_continuation(entry, GFP_ATOMIC);
 	return err;
 }
-- 
1.6.6

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