Commit b0a1c0d0 authored by Peter Xu's avatar Peter Xu Committed by Andrew Morton
Browse files

mm: remove follow_pte() 

follow_pte() users have been converted to follow_pfnmap*().  Remove the
API.

Link: https://lkml.kernel.org/r/20240826204353.2228736-17-peterx@redhat.com


Signed-off-by: default avatarPeter 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b17269a5

include/linux/mm.h

+0 −2
Original line number Diff line number Diff line
@@ -2368,8 +2368,6 @@ void free_pgd_range(struct mmu_gather *tlb, unsigned long addr, 
		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 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

+0 −73
Original line number Diff line number Diff line
@@ -6099,79 +6099,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 
}

#endif /* __PAGETABLE_PMD_FOLDED */



/**

 * follow_pte - look up PTE at a user virtual address

 * @vma: the memory mapping

 * @address: user virtual address

 * @ptepp: location to store found PTE

 * @ptlp: location to store the lock for the PTE

 *

 * On a successful return, the pointer to the PTE is stored in @ptepp;

 * the corresponding lock is taken and its location is stored in @ptlp.

 *

 * The contents of the PTE are only stable until @ptlp is released using

 * pte_unmap_unlock(). This function will fail if the PTE is non-present.

 * Present PTEs may include PTEs that map refcounted pages, such as

 * anonymous folios in COW mappings.

 *

 * Callers must be careful when relying on PTE content after

 * pte_unmap_unlock(). Especially if the PTE maps a refcounted page,

 * callers must protect against invalidation with MMU notifiers; otherwise

 * access to the PFN at a later point in time can trigger use-after-free.

 *

 * Only IO mappings and raw PFN mappings are allowed.  The mmap semaphore

 * should be taken for read.

 *

 * This function must not be used to modify PTE content.

 *

 * Return: zero on success, -ve otherwise.

 */

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;



	mmap_assert_locked(mm);

	if (unlikely(address < vma->vm_start || address >= vma->vm_end))

		goto out;



	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))

		goto out;



	pgd = pgd_offset(mm, address);

	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))

		goto out;



	p4d = p4d_offset(pgd, address);

	if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d)))

		goto out;



	pud = pud_offset(p4d, address);

	if (pud_none(*pud) || unlikely(pud_bad(*pud)))

		goto out;



	pmd = pmd_offset(pud, address);

	VM_BUG_ON(pmd_trans_huge(*pmd));



	ptep = pte_offset_map_lock(mm, pmd, address, ptlp);

	if (!ptep)

		goto out;

	if (!pte_present(ptep_get(ptep)))

		goto unlock;

	*ptepp = ptep;

	return 0;

unlock:

	pte_unmap_unlock(ptep, *ptlp);

out:

	return -EINVAL;

}

EXPORT_SYMBOL_GPL(follow_pte);



static inline void pfnmap_args_setup(struct follow_pfnmap_args *args,

				     spinlock_t *lock, pte_t *ptep,

				     pgprot_t pgprot, unsigned long pfn_base,