mm: simplify follow_pte{,pmd}

BugLink: https://bugs.launchpad.net/bugs/1918170
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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/fs/dax.c b/fs/dax.c
index cc56313c6b3b97b40a0b95c1c6d7fcf96bbaf7cd..31dae08acb09a578f1ceed560d9e67980db4b85c 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -794,12 +794,11 @@ static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index,
                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;
 
                /*

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d64166030f83075b206bc655a78e3d93f948082b..b5b8b4b9f0d422a9c29c1733e55b975aaf72dc44 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1466,9 +1466,9 @@ 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 mm_struct *dst, struct mm_struct *src,
                        struct vm_area_struct *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,

diff --git a/mm/memory.c b/mm/memory.c
index 5e34bb550b7764602535d94e8f157d20f1add424..4ede1d8a2c975994f09d23831b890aef1d1b2934 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4223,9 +4223,9 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 }
 #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;
@@ -4290,31 +4290,6 @@ 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
@@ -4335,7 +4310,7 @@ int follow_pfn(struct vm_area_struct *vma, unsigned long address,
        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);
@@ -4356,7 +4331,7 @@ int follow_phys(struct vm_area_struct *vma,
        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;