On Wed, Sep 23, 2026 at 2:28 PM Wen Jiang <[email protected]> wrote: > > vmap installs PTE-level block mappings by reusing set_huge_pte_at() and > huge_ptep_get_and_clear() under #ifdef CONFIG_HUGETLB_PAGE. This makes > the feature silently unavailable on CONFIG_HUGETLB_PAGE=n kernels and > couples mm/vmalloc.c to HugeTLB internals it does not otherwise need. > > Now that arm64 and powerpc/8xx provide pte_set_huge() and > pte_clear_huge(), add the generic fallbacks next to the existing > pmd/pud_set_huge() family and convert vmap_pte_range() and > vunmap_pte_range() to the new helpers. The CONFIG_HUGETLB_PAGE guards > around the block-mapping paths are dropped, so PTE-level block mappings > now also work on CONFIG_HUGETLB_PAGE=n kernels, and mm/vmalloc.c no > longer includes <linux/hugetlb.h>. > > The fallbacks exist only to keep the build working on architectures > without PTE-level block mapping support. They are unreachable there:
Since this is a `BUILD_BUG`, can the compiler simply eliminate the call? I guess the build would still pass even without the fallbacks, so this is more of a build-time check than something needed to keep the build passing? Am I missing something? > the callers only run when arch_vmap_pte_range_map_size() or > arch_vmap_pte_range_unmap_size() return a size other than PAGE_SIZE, > which requires an arch implementation. BUILD_BUG() makes that > explicit rather than silently doing nothing. > > Signed-off-by: Wen Jiang <[email protected]> Nice to see that `#ifdef CONFIG_HUGETLB_PAGE` and `#include <linux/hugetlb.h>` are no longer needed in `vmalloc`. Nothing concerns me except for the changelog issue mentioned above. Please double-check whether the changelog needs to be corrected. Reviewed-by: Barry Song <[email protected]>
