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mm/huge_memory: skip invalid debugfs new_order input for folio split

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User can put arbitrary new_order via debugfs for folio split test. 
Although new_order check is added to split_huge_page_to_list_order() in
the prior commit, these two additional checks can avoid unnecessary folio
locking and split_folio_to_order() calls.

Link: https://lkml.kernel.org/r/20240307181854.138928-2-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/linux-mm/7dda9283-b437-4cf8-ab0d-83c330deb9c0@moroto.mountain/
Cc: David Hildenbrand <david@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zi Yan 2024-03-07 13:18:54 -05:00 committed by Andrew Morton
parent 1412ecb3d2
commit 2394aef616
1 changed files with 6 additions and 0 deletions
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6
mm/huge_memory.c
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@ -3486,6 +3486,9 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start,
if (!is_transparent_hugepage(folio))
goto next;
if (new_order >= folio_order(folio))
goto next;
total++;
/*
* For folios with private, split_huge_page_to_list_to_order()
@ -3553,6 +3556,9 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start,
total++;
nr_pages = folio_nr_pages(folio);
if (new_order >= folio_order(folio))
goto next;
if (!folio_trylock(folio))
goto next;