From: Hugh Dickins hughd@google.com Subject: mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block
page_vma_mapped_walk() cleanup: rearrange the !pmd_present() block to follow the same "return not_found, return not_found, return true" pattern as the block above it (note: returning not_found there is never premature, since existence or prior existence of huge pmd guarantees good alignment).
Link: https://lkml.kernel.org/r/378c8650-1488-2edf-9647-32a53cf2e21@google.com Signed-off-by: Hugh Dickins hughd@google.com Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Reviewed-by: Peter Xu peterx@redhat.com Cc: Alistair Popple apopple@nvidia.com Cc: Matthew Wilcox willy@infradead.org Cc: Ralph Campbell rcampbell@nvidia.com Cc: Wang Yugui wangyugui@e16-tech.com Cc: Will Deacon will@kernel.org Cc: Yang Shi shy828301@gmail.com Cc: Zi Yan ziy@nvidia.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/page_vma_mapped.c | 30 ++++++++++++++---------------- 1 file changed, 14 insertions(+), 16 deletions(-)
--- a/mm/page_vma_mapped.c~mm-page_vma_mapped_walk-prettify-pvmw_migration-block +++ a/mm/page_vma_mapped.c @@ -198,24 +198,22 @@ restart: if (pmd_page(pmde) != page) return not_found(pvmw); return true; - } else if (!pmd_present(pmde)) { - if (thp_migration_supported()) { - if (!(pvmw->flags & PVMW_MIGRATION)) - return not_found(pvmw); - if (is_migration_entry(pmd_to_swp_entry(pmde))) { - swp_entry_t entry = pmd_to_swp_entry(pmde); + } + if (!pmd_present(pmde)) { + swp_entry_t entry;
- if (migration_entry_to_page(entry) != page) - return not_found(pvmw); - return true; - } - } - return not_found(pvmw); - } else { - /* THP pmd was split under us: handle on pte level */ - spin_unlock(pvmw->ptl); - pvmw->ptl = NULL; + if (!thp_migration_supported() || + !(pvmw->flags & PVMW_MIGRATION)) + return not_found(pvmw); + entry = pmd_to_swp_entry(pmde); + if (!is_migration_entry(entry) || + migration_entry_to_page(entry) != page) + return not_found(pvmw); + return true; } + /* THP pmd was split under us: handle on pte level */ + spin_unlock(pvmw->ptl); + pvmw->ptl = NULL; } else if (!pmd_present(pmde)) { /* * If PVMW_SYNC, take and drop THP pmd lock so that we _