The patch titled
mm: add comment on swap_duplicate's error code
has been added to the -mm tree. Its filename is
mm-add-comment-on-swap_duplicates-error-code.patch
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------------------------------------------------------
Subject: mm: add comment on swap_duplicate's error code
From: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
swap_duplicate()'s loop appears to miss out on returning the error code
from __swap_duplicate(), except when that's -ENOMEM. In fact this is
intentional: prior to -ENOMEM for swap_count_continuation,
swap_duplicate() was void (and the case only occurs when copy_one_pte()
hits a corrupt pte). But that's surprising behaviour, which certainly
deserves a comment.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Reported-by: Huang Shijie <shijie8@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff -puN mm/swapfile.c~mm-add-comment-on-swap_duplicates-error-code mm/swapfile.c
--- a/mm/swapfile.c~mm-add-comment-on-swap_duplicates-error-code
+++ a/mm/swapfile.c
@@ -2164,7 +2164,11 @@ void swap_shmem_alloc(swp_entry_t entry)
}
/*
- * increase reference count of swap entry by 1.
+ * Increase reference count of swap entry by 1.
+ * Returns 0 for success, or -ENOMEM if a swap_count_continuation is required
+ * but could not be atomically allocated. Returns 0, just as if it succeeded,
+ * if __swap_duplicate() fails for another reason (-EINVAL or -ENOENT), which
+ * might occur if a page table entry has got corrupted.
*/
int swap_duplicate(swp_entry_t entry)
{
_
Patches currently in -mm which might be from hugh.dickins@xxxxxxxxxxxxx are
mm-add-swap-slot-free-callback-to-block_device_operations.patch
genirq-warn-about-irqf_sharedirqf_disabled-at-the-right-place.patch
mlock_vma_pages_range-never-return-negative-value.patch
mlock_vma_pages_range-only-return-success-or-failure.patch
mm-fix-mbind-vma-merge-problem.patch
mm-fix-mbind-vma-merge-problem-fix.patch
mm-change-anon_vma-linking-to-fix-multi-process-server-scalability-issue.patch
mm-change-anon_vma-linking-to-fix-multi-process-server-scalability-issue-further-cleanups.patch
rmap-remove-obsolete-check-from-__page_check_anon_rmap.patch
rmap-move-exclusively-owned-pages-to-own-anon_vma-in-do_wp_page.patch
mm-swapfilec-fix-swapon-size-off-by-one.patch
mm-add-comment-on-swap_duplicates-error-code.patch
prio_tree-debugging-patch.patch
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