powerpc: mm: call ctor/dtor for kernel PTEs

The generic implementation of pte_{alloc_one,free}_kernel now calls the
[cd]tor, without initialising the ptlock needlessly as
pagetable_pte_ctor() skips it for init_mm.

On powerpc, all functions related to PTE allocation are implemented by
common helpers, which are passed a boolean to differentiate user from
kernel pgtables.  This patch aligns the powerpc implementation with the
generic one by calling pagetable_pte_[cd]tor() unconditionally in those
helpers.

Link: https://lkml.kernel.org/r/20250408095222.860601-6-kevin.brodsky@arm.com
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Waleij <linus.walleij@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <x86@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
index 387e9b1fe12cb6606462aadd3128f32d2ff42967..77e55eac16e42e748e652a67248f46f0c14afac9 100644 (file)
--- a/arch/powerpc/mm/pgtable-frag.c
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -56,19 +56,17 @@ static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
 {
        void *ret = NULL;
        struct ptdesc *ptdesc;
+       gfp_t gfp = PGALLOC_GFP;
 
-       if (!kernel) {
-               ptdesc = pagetable_alloc(PGALLOC_GFP | __GFP_ACCOUNT, 0);
-               if (!ptdesc)
-                       return NULL;
-               if (!pagetable_pte_ctor(mm, ptdesc)) {
-                       pagetable_free(ptdesc);
-                       return NULL;
-               }
-       } else {
-               ptdesc = pagetable_alloc(PGALLOC_GFP, 0);
-               if (!ptdesc)
-                       return NULL;
+       if (!kernel)
+               gfp |= __GFP_ACCOUNT;
+
+       ptdesc = pagetable_alloc(gfp, 0);
+       if (!ptdesc)
+               return NULL;
+       if (!pagetable_pte_ctor(mm, ptdesc)) {
+               pagetable_free(ptdesc);
+               return NULL;
        }
 
        atomic_set(&ptdesc->pt_frag_refcount, 1);
@@ -124,12 +122,10 @@ void pte_fragment_free(unsigned long *table, int kernel)
 
        BUG_ON(atomic_read(&ptdesc->pt_frag_refcount) <= 0);
        if (atomic_dec_and_test(&ptdesc->pt_frag_refcount)) {
-               if (kernel)
-                       pagetable_free(ptdesc);
-               else if (folio_test_clear_active(ptdesc_folio(ptdesc)))
-                       call_rcu(&ptdesc->pt_rcu_head, pte_free_now);
-               else
+               if (kernel || !folio_test_clear_active(ptdesc_folio(ptdesc)))
                        pte_free_now(&ptdesc->pt_rcu_head);
+               else
+                       call_rcu(&ptdesc->pt_rcu_head, pte_free_now);
        }
 }