[PATCH 5.10 14/23] mm: simplify follow_pte{,pmd}

Greg Kroah-Hartman
2021-02-25T10:13:50Z

From: Christoph Hellwig <hch@lst.de>

commit ff5c19ed4b087073cea38ff0edc80c23d7256943 upstream.

Merge __follow_pte_pmd, follow_pte_pmd and follow_pte into a single
follow_pte function and just pass two additional NULL arguments for the
two previous follow_pte callers.

[sfr@canb.auug.org.au: merge fix for "s390/pci: remove races against pte updates"]
Link: https://lkml.kernel.org/r/20201111221254.7f6a3658@canb.auug.org.au

Link: https://lkml.kernel.org/r/20201029101432.47011-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/dax.c | 9 ++++-----
include/linux/mm.h | 6 +++---
mm/memory.c | 35 +++++------------------------------
3 files changed, 12 insertions(+), 38 deletions(-)

--- a/fs/dax.c
+++ b/fs/dax.c
@@ -810,12 +810,11 @@ static void dax_entry_mkclean(struct add
address = pgoff_address(index, vma);

/*
- * Note because we provide range to follow_pte_pmd it will
- * call mmu_notifier_invalidate_range_start() on our behalf
- * before taking any lock.
+ * Note because we provide range to follow_pte it will call
+ * mmu_notifier_invalidate_range_start() on our behalf before
+ * taking any lock.
*/
- if (follow_pte_pmd(vma->vm_mm, address, &range,
- &ptep, &pmdp, &ptl))
+ if (follow_pte(vma->vm_mm, address, &range, &ptep, &pmdp, &ptl))
continue;

/*
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1655,9 +1655,9 @@ void free_pgd_range(struct mmu_gather *t
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_pmd(struct mm_struct *mm, unsigned long address,
- struct mmu_notifier_range *range,
- pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp);
+int follow_pte(struct mm_struct *mm, unsigned long address,
+ struct mmu_notifier_range *range, pte_t **ptepp, pmd_t **pmdpp,
+ 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,
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4707,9 +4707,9 @@ int __pmd_alloc(struct mm_struct *mm, pu
}
#endif /* __PAGETABLE_PMD_FOLDED */

-static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address,
- struct mmu_notifier_range *range,
- pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
+int follow_pte(struct mm_struct *mm, unsigned long address,
+ struct mmu_notifier_range *range, pte_t **ptepp, pmd_t **pmdpp,
+ spinlock_t **ptlp)
{
pgd_t *pgd;
p4d_t *p4d;
@@ -4774,31 +4774,6 @@ out:
return -EINVAL;
}

-static inline int follow_pte(struct mm_struct *mm, unsigned long address,
- pte_t **ptepp, spinlock_t **ptlp)
-{
- int res;
-
- /* (void) is needed to make gcc happy */
- (void) __cond_lock(*ptlp,
- !(res = __follow_pte_pmd(mm, address, NULL,
- ptepp, NULL, ptlp)));
- return res;
-}
-
-int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
- struct mmu_notifier_range *range,
- pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
-{
- int res;
-
- /* (void) is needed to make gcc happy */
- (void) __cond_lock(*ptlp,
- !(res = __follow_pte_pmd(mm, address, range,
- ptepp, pmdpp, ptlp)));
- return res;
-}
-
/**
* follow_pfn - look up PFN at a user virtual address
* @vma: memory mapping
@@ -4819,7 +4794,7 @@ int follow_pfn(struct vm_area_struct *vm
if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
return ret;

- ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
+ ret = follow_pte(vma->vm_mm, address, NULL, &ptep, NULL, &ptl);
if (ret)
return ret;
*pfn = pte_pfn(*ptep);
@@ -4840,7 +4815,7 @@ int follow_phys(struct vm_area_struct *v
if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
goto out;

- if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
+ if (follow_pte(vma->vm_mm, address, NULL, &ptep, NULL, &ptl))
goto out;
pte = *ptep;