mm/access_process_vm: use the new follow_pfnmap API

Use the new API that can understand huge pfn mappings.

Link: https://lkml.kernel.org/r/20240826204353.2228736-16-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.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: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.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: Ingo Molnar <mingo@redhat.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: Thomas Gleixner <tglx@linutronix.de>
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>

diff --git a/mm/memory.c b/mm/memory.c
index 3878bf69bc14cf59a43b967049328339899d1541..cfc278691466f5d3f3e1aea04a89c317d21e3eb2 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6341,34 +6341,34 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
        resource_size_t phys_addr;
        unsigned long prot = 0;
        void __iomem *maddr;
-       pte_t *ptep, pte;
-       spinlock_t *ptl;
        int offset = offset_in_page(addr);
        int ret = -EINVAL;
+       bool writable;
+       struct follow_pfnmap_args args = { .vma = vma, .address = addr };
 
 retry:
-       if (follow_pte(vma, addr, &ptep, &ptl))
+       if (follow_pfnmap_start(&args))
                return -EINVAL;
-       pte = ptep_get(ptep);
-       pte_unmap_unlock(ptep, ptl);
+       prot = pgprot_val(args.pgprot);
+       phys_addr = (resource_size_t)args.pfn << PAGE_SHIFT;
+       writable = args.writable;
+       follow_pfnmap_end(&args);
 
-       prot = pgprot_val(pte_pgprot(pte));
-       phys_addr = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
-
-       if ((write & FOLL_WRITE) && !pte_write(pte))
+       if ((write & FOLL_WRITE) && !writable)
                return -EINVAL;
 
        maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
        if (!maddr)
                return -ENOMEM;
 
-       if (follow_pte(vma, addr, &ptep, &ptl))
+       if (follow_pfnmap_start(&args))
                goto out_unmap;
 
-       if (!pte_same(pte, ptep_get(ptep))) {
-               pte_unmap_unlock(ptep, ptl);
+       if ((prot != pgprot_val(args.pgprot)) ||
+           (phys_addr != (args.pfn << PAGE_SHIFT)) ||
+           (writable != args.writable)) {
+               follow_pfnmap_end(&args);
                iounmap(maddr);
-
                goto retry;
        }
 
@@ -6377,7 +6377,7 @@ retry:
        else
                memcpy_fromio(buf, maddr + offset, len);
        ret = len;
-       pte_unmap_unlock(ptep, ptl);
+       follow_pfnmap_end(&args);
 out_unmap:
        iounmap(maddr);