linux-kernel - [PATCH] powerpc: Remove find_current_mm

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Message-Id: <ec79f462a3bfa8365b7df505e574d5d85246bc68.1646818177.git.christophe.leroy@csgroup.eu>
Date:   Wed,  9 Mar 2022 10:29:50 +0100
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] powerpc: Remove find_current_mm_pte()

Last usage of find_current_mm_pte() was removed by
commit 15759cb054ef ("powerpc/perf/callchain: Use
__get_user_pages_fast in read_user_stack_slow")

Remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/include/asm/pte-walk.h | 25 -------------------------
 arch/powerpc/mm/book3s64/pgtable.c  |  4 ++--
 2 files changed, 2 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/include/asm/pte-walk.h b/arch/powerpc/include/asm/pte-walk.h
index 714a35f0d425..73c22c579a79 100644
--- a/arch/powerpc/include/asm/pte-walk.h
+++ b/arch/powerpc/include/asm/pte-walk.h
@@ -60,29 +60,4 @@ static inline phys_addr_t ppc_find_vmap_phys(unsigned long addr)
 	return pa;
 }
 
-/*
- * This is what we should always use. Any other lockless page table lookup needs
- * careful audit against THP split.
- */
-static inline pte_t *find_current_mm_pte(pgd_t *pgdir, unsigned long ea,
-					 bool *is_thp, unsigned *hshift)
-{
-	pte_t *pte;
-
-	VM_WARN(!arch_irqs_disabled(), "%s called with irq enabled\n", __func__);
-	VM_WARN(pgdir != current->mm->pgd,
-		"%s lock less page table lookup called on wrong mm\n", __func__);
-	pte = __find_linux_pte(pgdir, ea, is_thp, hshift);
-
-#if defined(CONFIG_DEBUG_VM) &&						\
-	!(defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE))
-	/*
-	 * We should not find huge page if these configs are not enabled.
-	 */
-	if (hshift)
-		WARN_ON(*hshift);
-#endif
-	return pte;
-}
-
 #endif /* _ASM_POWERPC_PTE_WALK_H */
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 79ce3c22a29d..41a41357799d 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -98,14 +98,14 @@ static void do_serialize(void *arg)
 }
 
 /*
- * Serialize against find_current_mm_pte which does lock-less
+ * Serialize against __find_linux_pte() which does lock-less
  * lookup in page tables with local interrupts disabled. For huge pages
  * it casts pmd_t to pte_t. Since format of pte_t is different from
  * pmd_t we want to prevent transit from pmd pointing to page table
  * to pmd pointing to huge page (and back) while interrupts are disabled.
  * We clear pmd to possibly replace it with page table pointer in
  * different code paths. So make sure we wait for the parallel
- * find_current_mm_pte to finish.
+ * __find_linux_pte() to finish.
  */
 void serialize_against_pte_lookup(struct mm_struct *mm)
 {
-- 
2.34.1