Re: [PATCH v2 1/3] sparc/mm: drop custom pte_clear_not_present_full()

[Lance Yang <lance.yang@linux.dev>]

On Mon, Jun 29, 2026 at 03:49:47PM +0200, David Hildenbrand (Arm) wrote:
>On sparc64, pte_clear_not_present_full() nowadays does a simple
>__set_pte_at(). In __set_pte_at() -> maybe_tlb_batch_add(), we check
>pte_accessible() to see whether to call tlb_batch_add().
>
>However, non-present PTEs are surely not accessible, so tlb_batch_add()
>is never called and the "full" parameter is irrelevant.
>
>Let's drop the helper and just let common code do a pte_clear().
>
>pte_clear() on sparc64 maps to set_pte_at()->set_ptes()->__set_pte_at()
>... so it ends up calling the same function, just with "full=0".
>
>Given that "full" is irrelevant, there is no change.
>
>We added pte_clear_not_present_full() for sparc64 in commit 90f08e399d05
>("sparc: mmu_gather rework"), and I suspect that it was already not
>required back then.
>
>Cc: Peter Zijlstra <peterz@infradead.org>
>Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
>---

fullmm only matters if an old non-present PTE can pass pte_accessible().
IIUC, that doesn't happen on sparc64 :)

LGTM. Feel free to add:

Reviewed-by: Lance Yang <lance.yang@linux.dev>