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John Hubbard
c36c04c2e1
This reverts commit54d516b1d6That commit did a refactoring that effectively combined fast and slow gup paths (again). And that was again incorrect, for two reasons: a) Fast gup and slow gup get reference counts on pages in different ways and with different goals: see Linus' writeup in commitcd1adf1b63("Revert "mm/gup: remove try_get_page(), call try_get_compound_head() directly""), and b) try_grab_compound_head() also has a specific check for "FOLL_LONGTERM && !is_pinned(page)", that assumes that the caller can fall back to slow gup. This resulted in new failures, as recently report by Will McVicker [1]. But (a) has problems too, even though they may not have been reported yet. So just revert this. Link: https://lore.kernel.org/r/[email protected] [1] Fixes:54d516b1d6("mm/gup: small refactoring: simplify try_grab_page()") Reported-and-tested-by: Will McVicker <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Christian Borntraeger <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Vasily Gorbik <[email protected]> Cc: [email protected] # 5.15 Signed-off-by: John Hubbard <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>