mm: remove follow_pfn

jira LE-3557
Rebuild_History Non-Buildable kernel-5.14.0-570.26.1.el9_6
commit-author Christoph Hellwig <[email protected]>
commit cb10c28
Empty-Commit: Cherry-Pick Conflicts during history rebuild.
Will be included in final tarball splat. Ref for failed cherry-pick at:
ciq/ciq_backports/kernel-5.14.0-570.26.1.el9_6/cb10c28a.failed

Remove follow_pfn now that the last user is gone.

Link: https://lkml.kernel.org/r/[email protected]
	Signed-off-by: Christoph Hellwig <[email protected]>
	Reviewed-by: David Hildenbrand <[email protected]>
	Cc: Andy Lutomirski <[email protected]>
	Cc: Dave Hansen <[email protected]>
	Cc: Fei Li <[email protected]>
	Cc: Ingo Molnar <[email protected]>
	Cc: Peter Zijlstra <[email protected]>
	Cc: Nathan Chancellor <[email protected]>
	Signed-off-by: Andrew Morton <[email protected]>
(cherry picked from commit cb10c28)
	Signed-off-by: Jonathan Maple <[email protected]>

# Conflicts:
#	mm/nommu.c

Author: PlaidCat

ciq/ciq_backports/kernel-5.14.0-570.26.1.el9_6/cb10c28a.failed

@@ -0,0 +1,132 @@
+mm: remove follow_pfn
+
+jira LE-3557
+Rebuild_History Non-Buildable kernel-5.14.0-570.26.1.el9_6
+commit-author Christoph Hellwig <[email protected]>
+commit cb10c28ac82c9b7a5e9b3b1dc7157036c20c36dd
+Empty-Commit: Cherry-Pick Conflicts during history rebuild.
+Will be included in final tarball splat. Ref for failed cherry-pick at:
+ciq/ciq_backports/kernel-5.14.0-570.26.1.el9_6/cb10c28a.failed
+
+Remove follow_pfn now that the last user is gone.
+
+Link: https://lkml.kernel.org/r/[email protected]
+	Signed-off-by: Christoph Hellwig <[email protected]>
+	Reviewed-by: David Hildenbrand <[email protected]>
+	Cc: Andy Lutomirski <[email protected]>
+	Cc: Dave Hansen <[email protected]>
+	Cc: Fei Li <[email protected]>
+	Cc: Ingo Molnar <[email protected]>
+	Cc: Peter Zijlstra <[email protected]>
+	Cc: Nathan Chancellor <[email protected]>
+	Signed-off-by: Andrew Morton <[email protected]>
+(cherry picked from commit cb10c28ac82c9b7a5e9b3b1dc7157036c20c36dd)
+	Signed-off-by: Jonathan Maple <[email protected]>
+
+# Conflicts:
+#	mm/nommu.c
+diff --cc mm/nommu.c
+index f3f6a7e97647,331d2f778695..000000000000
+--- a/mm/nommu.c
++++ b/mm/nommu.c
+@@@ -110,29 -110,6 +110,32 @@@ unsigned int kobjsize(const void *objp
+  	return page_size(page);
+  }
+  
+++<<<<<<< HEAD
+ +/**
+ + * follow_pfn - look up PFN at a user virtual address
+ + * @vma: memory mapping
+ + * @address: user virtual address
+ + * @pfn: location to store found PFN
+ + *
+ + * Only IO mappings and raw PFN mappings are allowed.
+ + *
+ + * Returns zero and the pfn at @pfn on success, -ve otherwise.
+ + */
+ +int follow_pfn(struct vm_area_struct *vma, unsigned long address,
+ +	unsigned long *pfn)
+ +{
+ +	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+ +		return -EINVAL;
+ +
+ +	*pfn = address >> PAGE_SHIFT;
+ +	return 0;
+ +}
+ +EXPORT_SYMBOL(follow_pfn);
+ +
+ +LIST_HEAD(vmap_area_list);
+ +
+++=======
+++>>>>>>> cb10c28ac82c (mm: remove follow_pfn)
+  void vfree(const void *addr)
+  {
+  	kfree(addr);
+diff --git a/include/linux/mm.h b/include/linux/mm.h
+index 196c481ec160..cd16e4cb2ce0 100644
+--- a/include/linux/mm.h
++++ b/include/linux/mm.h
+@@ -2429,8 +2429,6 @@ 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,
+ 	       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,
+diff --git a/mm/memory.c b/mm/memory.c
+index e2794e3b8919..4498a39fb51d 100644
+--- a/mm/memory.c
++++ b/mm/memory.c
+@@ -5623,8 +5623,8 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
+  * Only IO mappings and raw PFN mappings are allowed.  The mmap semaphore
+  * should be taken for read.
+  *
+- * KVM uses this function.  While it is arguably less bad than ``follow_pfn``,
+- * it is not a good general-purpose API.
++ * KVM uses this function.  While it is arguably less bad than the historic
++ * ``follow_pfn``, it is not a good general-purpose API.
+  *
+  * Return: zero on success, -ve otherwise.
+  */
+@@ -5666,38 +5666,6 @@ int follow_pte(struct mm_struct *mm, unsigned long address,
+ }
+ EXPORT_SYMBOL_GPL(follow_pte);
+ 
+-/**
+- * follow_pfn - look up PFN at a user virtual address
+- * @vma: memory mapping
+- * @address: user virtual address
+- * @pfn: location to store found PFN
+- *
+- * Only IO mappings and raw PFN mappings are allowed.
+- *
+- * This function does not allow the caller to read the permissions
+- * of the PTE.  Do not use it.
+- *
+- * Return: zero and the pfn at @pfn on success, -ve otherwise.
+- */
+-int follow_pfn(struct vm_area_struct *vma, unsigned long address,
+-	unsigned long *pfn)
+-{
+-	int ret = -EINVAL;
+-	spinlock_t *ptl;
+-	pte_t *ptep;
+-
+-	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
+-		return ret;
+-
+-	ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
+-	if (ret)
+-		return ret;
+-	*pfn = pte_pfn(ptep_get(ptep));
+-	pte_unmap_unlock(ptep, ptl);
+-	return 0;
+-}
+-EXPORT_SYMBOL(follow_pfn);
+-
+ #ifdef CONFIG_HAVE_IOREMAP_PROT
+ int follow_phys(struct vm_area_struct *vma,
+ 		unsigned long address, unsigned int flags,
+* Unmerged path mm/nommu.c