linux-kernel - [PATCH -next 1/2] x86/mm/pat: Move follow

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Date:   Mon, 6 Mar 2023 16:43:15 +0800
From:   Wupeng Ma <mawupeng1@...wei.com>
To:     <akpm@...ux-foundation.org>, <dave.hansen@...ux.intel.com>,
        <luto@...nel.org>, <peterz@...radead.org>
CC:     <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        <mawupeng1@...wei.com>
Subject: [PATCH -next 1/2] x86/mm/pat: Move follow_phys to pat-related file

From: Ma Wupeng <mawupeng1@...wei.com>

Since only PAT in x86 use follow_phys(), move this to from memory.c to
memtype.c and make it static. Argument flags is always zero in caller
untrack_pfn() and track_pfn_copy(). let's drop it.

Since config HAVE_IOREMAP_PROT is selected by x86, drop this config macro.

Signed-off-by: Ma Wupeng <mawupeng1@...wei.com>
---
 arch/x86/mm/pat/memtype.c | 27 +++++++++++++++++++++++++--
 include/linux/mm.h        |  2 --
 mm/memory.c               | 28 ----------------------------
 3 files changed, 25 insertions(+), 32 deletions(-)

diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index de10800cd4dd..c138ea0b0e6e 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -950,6 +950,29 @@ static void free_pfn_range(u64 paddr, unsigned long size)
 		memtype_free(paddr, paddr + size);
 }
 
+static int follow_phys(struct vm_area_struct *vma, unsigned long address,
+		       unsigned long *prot, resource_size_t *phys)
+{
+	int ret = -EINVAL;
+	pte_t *ptep, pte;
+	spinlock_t *ptl;
+
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out;
+
+	if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
+		goto out;
+	pte = *ptep;
+
+	*prot = pgprot_val(pte_pgprot(pte));
+	*phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
+
+	ret = 0;
+	pte_unmap_unlock(ptep, ptl);
+out:
+	return ret;
+}
+
 /*
  * track_pfn_copy is called when vma that is covering the pfnmap gets
  * copied through copy_page_range().
@@ -969,7 +992,7 @@ int track_pfn_copy(struct vm_area_struct *vma)
 		 * reserve the whole chunk covered by vma. We need the
 		 * starting address and protection from pte.
 		 */
-		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
+		if (follow_phys(vma, vma->vm_start, &prot, &paddr)) {
 			WARN_ON_ONCE(1);
 			return -EINVAL;
 		}
@@ -1056,7 +1079,7 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 	/* free the chunk starting from pfn or the whole chunk */
 	paddr = (resource_size_t)pfn << PAGE_SHIFT;
 	if (!paddr && !size) {
-		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
+		if (follow_phys(vma, vma->vm_start, &prot, &paddr)) {
 			WARN_ON_ONCE(1);
 			return;
 		}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5f16263d176d..226f2f7cefd7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2311,8 +2311,6 @@ int follow_pte(struct mm_struct *mm, unsigned long address,
 	       pte_t **ptepp, spinlock_t **ptlp);
 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
 	unsigned long *pfn);
-int follow_phys(struct vm_area_struct *vma, unsigned long address,
-		unsigned int flags, unsigned long *prot, resource_size_t *phys);
 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
 			void *buf, int len, int write);
 
diff --git a/mm/memory.c b/mm/memory.c
index 0adf23ea5416..93ad6b45f426 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5454,34 +5454,6 @@ int follow_pfn(struct vm_area_struct *vma, unsigned long address,
 EXPORT_SYMBOL(follow_pfn);
 
 #ifdef CONFIG_HAVE_IOREMAP_PROT
-int follow_phys(struct vm_area_struct *vma,
-		unsigned long address, unsigned int flags,
-		unsigned long *prot, resource_size_t *phys)
-{
-	int ret = -EINVAL;
-	pte_t *ptep, pte;
-	spinlock_t *ptl;
-
-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
-		goto out;
-
-	if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
-		goto out;
-	pte = *ptep;
-
-	if ((flags & FOLL_WRITE) && !pte_write(pte))
-		goto unlock;
-
-	*prot = pgprot_val(pte_pgprot(pte));
-	*phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
-
-	ret = 0;
-unlock:
-	pte_unmap_unlock(ptep, ptl);
-out:
-	return ret;
-}
-
 /**
  * generic_access_phys - generic implementation for iomem mmap access
  * @vma: the vma to access
-- 
2.25.1