linux-kernel - [PATCH v13 18/18] arm64/mm: remove useless trans_pgd_map

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Date:   Thu,  8 Apr 2021 00:05:37 -0400
From:   Pavel Tatashin <pasha.tatashin@...een.com>
To:     pasha.tatashin@...een.com, jmorris@...ei.org, sashal@...nel.org,
        ebiederm@...ssion.com, kexec@...ts.infradead.org,
        linux-kernel@...r.kernel.org, corbet@....net,
        catalin.marinas@....com, will@...nel.org,
        linux-arm-kernel@...ts.infradead.org, maz@...nel.org,
        james.morse@....com, vladimir.murzin@....com,
        matthias.bgg@...il.com, linux-mm@...ck.org, mark.rutland@....com,
        steve.capper@....com, rfontana@...hat.com, tglx@...utronix.de,
        selindag@...il.com, tyhicks@...ux.microsoft.com,
        kernelfans@...il.com
Subject: [PATCH v13 18/18] arm64/mm: remove useless trans_pgd_map_page()

From: Pingfan Liu <kernelfans@...il.com>

The intend of trans_pgd_map_page() was to map contigous range of VA
memory to the memory that is getting relocated during kexec. However,
since we are now using linear map instead of contigous range this
function is not needed

Signed-off-by: Pingfan Liu <kernelfans@...il.com>
[Changed commit message]
Signed-off-by: Pavel Tatashin <pasha.tatashin@...een.com>
---
 arch/arm64/include/asm/trans_pgd.h |  5 +--
 arch/arm64/mm/trans_pgd.c          | 57 ------------------------------
 2 files changed, 1 insertion(+), 61 deletions(-)

diff --git a/arch/arm64/include/asm/trans_pgd.h b/arch/arm64/include/asm/trans_pgd.h
index e0760e52d36d..234353df2f13 100644
--- a/arch/arm64/include/asm/trans_pgd.h
+++ b/arch/arm64/include/asm/trans_pgd.h
@@ -15,7 +15,7 @@
 /*
  * trans_alloc_page
  *	- Allocator that should return exactly one zeroed page, if this
- *	  allocator fails, trans_pgd_create_copy() and trans_pgd_map_page()
+ *	  allocator fails, trans_pgd_create_copy() and trans_pgd_idmap_page()
  *	  return -ENOMEM error.
  *
  * trans_alloc_arg
@@ -30,9 +30,6 @@ struct trans_pgd_info {
 int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **trans_pgd,
 			  unsigned long start, unsigned long end);
 
-int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
-		       void *page, unsigned long dst_addr, pgprot_t pgprot);
-
 int trans_pgd_idmap_page(struct trans_pgd_info *info, phys_addr_t *trans_ttbr0,
 			 unsigned long *t0sz, void *page);
 
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index 61549451ed3a..e24a749013c1 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -217,63 +217,6 @@ int trans_pgd_create_copy(struct trans_pgd_info *info, pgd_t **dst_pgdp,
 	return rc;
 }
 
-/*
- * Add map entry to trans_pgd for a base-size page at PTE level.
- * info:	contains allocator and its argument
- * trans_pgd:	page table in which new map is added.
- * page:	page to be mapped.
- * dst_addr:	new VA address for the page
- * pgprot:	protection for the page.
- *
- * Returns 0 on success, and -ENOMEM on failure.
- */
-int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
-		       void *page, unsigned long dst_addr, pgprot_t pgprot)
-{
-	pgd_t *pgdp;
-	p4d_t *p4dp;
-	pud_t *pudp;
-	pmd_t *pmdp;
-	pte_t *ptep;
-
-	pgdp = pgd_offset_pgd(trans_pgd, dst_addr);
-	if (pgd_none(READ_ONCE(*pgdp))) {
-		p4dp = trans_alloc(info);
-		if (!pgdp)
-			return -ENOMEM;
-		pgd_populate(NULL, pgdp, p4dp);
-	}
-
-	p4dp = p4d_offset(pgdp, dst_addr);
-	if (p4d_none(READ_ONCE(*p4dp))) {
-		pudp = trans_alloc(info);
-		if (!pudp)
-			return -ENOMEM;
-		p4d_populate(NULL, p4dp, pudp);
-	}
-
-	pudp = pud_offset(p4dp, dst_addr);
-	if (pud_none(READ_ONCE(*pudp))) {
-		pmdp = trans_alloc(info);
-		if (!pmdp)
-			return -ENOMEM;
-		pud_populate(NULL, pudp, pmdp);
-	}
-
-	pmdp = pmd_offset(pudp, dst_addr);
-	if (pmd_none(READ_ONCE(*pmdp))) {
-		ptep = trans_alloc(info);
-		if (!ptep)
-			return -ENOMEM;
-		pmd_populate_kernel(NULL, pmdp, ptep);
-	}
-
-	ptep = pte_offset_kernel(pmdp, dst_addr);
-	set_pte(ptep, pfn_pte(virt_to_pfn(page), pgprot));
-
-	return 0;
-}
-
 /*
  * The page we want to idmap may be outside the range covered by VA_BITS that
  * can be built using the kernel's p?d_populate() helpers. As a one off, for a
-- 
2.25.1