Commit 8e8299bf authored Apr 08, 2025 by Kevin Brodsky Committed by Andrew Morton May 11, 2025

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>

parent 5a392e99

arch/powerpc/mm/pgtable-frag.c

+13 −17

Original line number	Diff line number	Diff line
		@@ -56,20 +56,18 @@ 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 (!kernel)
		gfp \|= __GFP_ACCOUNT;

		ptdesc = pagetable_alloc(gfp, 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;
		}

		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);
		}
		}