The patch titled
Subject: mm: remove follow_pfn
has been added to the -mm mm-unstable branch. Its filename is
mm-remove-follow_pfn.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-remove-follow_pfn.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: mm: remove follow_pfn
Date: Mon, 25 Mar 2024 07:45:41 +0800
Remove follow_pfn now that the last user is gone.
Link: https://lkml.kernel.org/r/20240324234542.2038726-3-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fei Li <fei1.li@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 2 --
mm/memory.c | 36 ++----------------------------------
mm/nommu.c | 21 ---------------------
3 files changed, 2 insertions(+), 57 deletions(-)
--- a/include/linux/mm.h~mm-remove-follow_pfn
+++ a/include/linux/mm.h
@@ -2424,8 +2424,6 @@ 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,
--- a/mm/memory.c~mm-remove-follow_pfn
+++ a/mm/memory.c
@@ -5884,8 +5884,8 @@ int __pmd_alloc(struct mm_struct *mm, pu
* 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.
*/
@@ -5927,38 +5927,6 @@ out:
}
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,
--- a/mm/nommu.c~mm-remove-follow_pfn
+++ a/mm/nommu.c
@@ -110,27 +110,6 @@ unsigned int kobjsize(const void *objp)
return page_size(page);
}
-/**
- * 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);
-
void vfree(const void *addr)
{
kfree(addr);
_
Patches currently in -mm which might be from hch@xxxxxx are
virt-acrn-stop-using-follow_pfn.patch
mm-remove-follow_pfn.patch
mm-move-follow_phys-to-arch-x86-mm-pat-memtypec.patch
