mm/x86/pat: use the new follow_pfnmap API

JIRA: https://issues.redhat.com/browse/RHEL-73613

commit cbea853
Author: Peter Xu <peterx@redhat.com>
Date:   Mon Aug 26 16:43:46 2024 -0400

    mm/x86/pat: use the new follow_pfnmap API

    Use the new API that can understand huge pfn mappings.

    Link: https://lkml.kernel.org/r/20240826204353.2228736-13-peterx@redhat.com
    Signed-off-by: Peter Xu <peterx@redhat.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Alexander Gordeev <agordeev@linux.ibm.com>
    Cc: Alex Williamson <alex.williamson@redhat.com>
    Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
    Cc: David Hildenbrand <david@redhat.com>
    Cc: Gavin Shan <gshan@redhat.com>
    Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
    Cc: Heiko Carstens <hca@linux.ibm.com>
    Cc: Jason Gunthorpe <jgg@nvidia.com>
    Cc: Matthew Wilcox <willy@infradead.org>
    Cc: Niklas Schnelle <schnelle@linux.ibm.com>
    Cc: Paolo Bonzini <pbonzini@redhat.com>
    Cc: Ryan Roberts <ryan.roberts@arm.com>
    Cc: Sean Christopherson <seanjc@google.com>
    Cc: Sven Schnelle <svens@linux.ibm.com>
    Cc: Vasily Gorbik <gor@linux.ibm.com>
    Cc: Will Deacon <will@kernel.org>
    Cc: Zi Yan <ziy@nvidia.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Donald Dutile <ddutile@redhat.com>

Author: ddutile

arch/x86/mm/pat/memtype.c

@@ -951,23 +951,20 @@ static void free_pfn_range(u64 paddr, unsigned long size)
 static int follow_phys(struct vm_area_struct *vma, unsigned long *prot,
 		resource_size_t *phys)
 {
-	pte_t *ptep, pte;
-	spinlock_t *ptl;
+	struct follow_pfnmap_args args = { .vma = vma, .address = vma->vm_start };
 
-	if (follow_pte(vma, vma->vm_start, &ptep, &ptl))
+	if (follow_pfnmap_start(&args))
 		return -EINVAL;
 
-	pte = ptep_get(ptep);
-
 	/* Never return PFNs of anon folios in COW mappings. */
-	if (vm_normal_folio(vma, vma->vm_start, pte)) {
-		pte_unmap_unlock(ptep, ptl);
+	if (!args.special) {
+		follow_pfnmap_end(&args);
 		return -EINVAL;
 	}
 
-	*prot = pgprot_val(pte_pgprot(pte));
-	*phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
-	pte_unmap_unlock(ptep, ptl);
+	*prot = pgprot_val(args.pgprot);
+	*phys = (resource_size_t)args.pfn << PAGE_SHIFT;
+	follow_pfnmap_end(&args);
 	return 0;
 }