mm: pass page directly instead of using folio_page

In commit_anon_folio_batch(), we iterate over all pages pointed to by the
PTE batch.  Therefore we need to know the first page of the batch;
currently we derive that via folio_page(folio, 0), but, that takes us to
the first (head) page of the folio instead - our PTE batch may lie in the
middle of the folio, leading to incorrectness.

Bite the bullet and throw away the micro-optimization of reusing the folio
in favour of code simplicity.  Derive the page and the folio in
change_pte_range, and pass the page too to commit_anon_folio_batch to fix
the aforementioned issue.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: cac1db8c3aad ("mm: optimize mprotect() by PTE batching")
Reported-by: [email protected]
Signed-off-by: Dev Jain <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Debugged-by: David Hildenbrand <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Joey Gouly <[email protected]>
Cc: Kevin Brodsky <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Yicong Yang <[email protected]>
Cc: Zhenhua Huang <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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