Commit 08259d58 authored Mar 05, 2010 by Hugh Dickins Committed by Linus Torvalds Mar 06, 2010

mm: add comment on swap_duplicate's error code



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@google.com>
Reported-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c08c6e1f

mm/swapfile.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -2161,7 +2161,11 @@ 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)
		{

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