mm/huge_memory: fix lockdep complaint on 32-bit i_size_read()
Huge tmpfs testing, on 32-bit kernel with lockdep enabled, showed that __split_huge_page() was using i_size_read() while holding the irq-safe lru_lock and page tree lock, but the 32-bit i_size_read() uses an irq-unsafe seqlock which should not be nested inside them. Instead, read the i_size earlier in split_huge_page_to_list(), and pass the end offset down to __split_huge_page(): all while holding head page lock, which is enough to prevent truncation of that extent before the page tree lock has been taken. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261520070.2275@eggly.anvils Fixes: baa355fd ("thp: file pages support for split_huge_page()") Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Matthew Wilcox <willy@infradead.org> Cc: <stable@vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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