mm: pass VMA instead of MM to follow_pte()

... and centralize the VM_IO/VM_PFNMAP sanity check in there. We'll
now also perform these sanity checks for direct follow_pte()
invocations.

For generic_access_phys(), we might now check multiple times: nothing to
worry about, really.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: David Hildenbrand <[e-mail]>
Acked-by: Sean Christopherson <[e-mail]> [KVM]
Cc: Alex Williamson <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Fei Li <[e-mail]>
Cc: Gerald Schaefer <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Cc: Yonghua Huang <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

arch/s390/pci/pci_mmio.c

···
 	if (!(vma->vm_flags & VM_WRITE))
 		goto out_unlock_mmap;
 
-	ret = follow_pte(vma->vm_mm, mmio_addr, &ptep, &ptl);
+	ret = follow_pte(vma, mmio_addr, &ptep, &ptl);
 	if (ret)
 		goto out_unlock_mmap;
 
···
 	if (!(vma->vm_flags & VM_WRITE))
 		goto out_unlock_mmap;
 
-	ret = follow_pte(vma->vm_mm, mmio_addr, &ptep, &ptl);
+	ret = follow_pte(vma, mmio_addr, &ptep, &ptl);
 	if (ret)
 		goto out_unlock_mmap;
 

arch/x86/mm/pat/memtype.c

···
 	pte_t *ptep, pte;
 	spinlock_t *ptl;
 
-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
-		return -EINVAL;
-
-	if (follow_pte(vma->vm_mm, vma->vm_start, &ptep, &ptl))
+	if (follow_pte(vma, vma->vm_start, &ptep, &ptl))
 		return -EINVAL;
 
 	pte = ptep_get(ptep);

drivers/vfio/vfio_iommu_type1.c

···
 	spinlock_t *ptl;
 	int ret;
 
-	ret = follow_pte(vma->vm_mm, vaddr, &ptep, &ptl);
+	ret = follow_pte(vma, vaddr, &ptep, &ptl);
 	if (ret) {
 		bool unlocked = false;
 
···
 		if (ret)
 			return ret;
 
-		ret = follow_pte(vma->vm_mm, vaddr, &ptep, &ptl);
+		ret = follow_pte(vma, vaddr, &ptep, &ptl);
 		if (ret)
 			return ret;
 	}

drivers/virt/acrn/mm.c

···
 		}
 
 		for (i = 0; i < nr_pages; i++) {
-			ret = follow_pte(vma->vm_mm,
-					 memmap->vma_base + i * PAGE_SIZE,
+			ret = follow_pte(vma, memmap->vma_base + i * PAGE_SIZE,
 					 &ptep, &ptl);
 			if (ret)
 				break;

include/linux/mm.h

···
 		unsigned long end, unsigned long floor, unsigned long ceiling);
 int
 copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma);
-int follow_pte(struct mm_struct *mm, unsigned long address,
+int follow_pte(struct vm_area_struct *vma, unsigned long address,
 	       pte_t **ptepp, spinlock_t **ptlp);
 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
 			void *buf, int len, int write);

mm/memory.c

···
 
 /**
  * follow_pte - look up PTE at a user virtual address
- * @mm: the mm_struct of the target address space
+ * @vma: the memory mapping
  * @address: user virtual address
  * @ptepp: location to store found PTE
  * @ptlp: location to store the lock for the PTE
···
  *
  * Return: zero on success, -ve otherwise.
  */
-int follow_pte(struct mm_struct *mm, unsigned long address,
+int follow_pte(struct vm_area_struct *vma, unsigned long address,
 	       pte_t **ptepp, spinlock_t **ptlp)
 {
+	struct mm_struct *mm = vma->vm_mm;
 	pgd_t *pgd;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *ptep;
+
+	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+		goto out;
 
 	pgd = pgd_offset(mm, address);
 	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
···
 	int offset = offset_in_page(addr);
 	int ret = -EINVAL;
 
-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
-		return -EINVAL;
-
 retry:
-	if (follow_pte(vma->vm_mm, addr, &ptep, &ptl))
+	if (follow_pte(vma, addr, &ptep, &ptl))
 		return -EINVAL;
 	pte = ptep_get(ptep);
 	pte_unmap_unlock(ptep, ptl);
···
 	if (!maddr)
 		return -ENOMEM;
 
-	if (follow_pte(vma->vm_mm, addr, &ptep, &ptl))
+	if (follow_pte(vma, addr, &ptep, &ptl))
 		goto out_unmap;
 
 	if (!pte_same(pte, ptep_get(ptep))) {

virt/kvm/kvm_main.c

···
 	spinlock_t *ptl;
 	int r;
 
-	r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
+	r = follow_pte(vma, addr, &ptep, &ptl);
 	if (r) {
 		/*
 		 * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does
···
 		if (r)
 			return r;
 
-		r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
+		r = follow_pte(vma, addr, &ptep, &ptl);
 		if (r)
 			return r;
 	}