mm: pagewalk: move variables to more local scope, tweak loops

Move some variables to more local scopes to make it obvious that they
don't carry state.  Put the end additions into the for loop instructions
to make them easier to read.

Link: https://lkml.kernel.org/r/8155217.NyiUUSuA9g@devpool047
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 7629838eea13ec97d193b279d2c2ee6529126b25..54b2a1beeeb3ba7f1c89b9b0b60616052f570d64 100644 (file)
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -25,14 +25,12 @@ static int walk_pte_range_inner(pte_t *pte, unsigned long addr,
 {
        const struct mm_walk_ops *ops = walk->ops;
 
-       for (;;) {
+       for (;; addr += PAGE_SIZE, pte++) {
                int err = ops->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
                if (err)
                        return err;
                if (addr >= end - PAGE_SIZE)
                        break;
-               addr += PAGE_SIZE;
-               pte++;
        }
        return 0;
 }
@@ -42,13 +40,14 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 {
        pte_t *pte;
        int err;
-       spinlock_t *ptl;
 
        if (walk->no_vma) {
                pte = pte_offset_map(pmd, addr);
                err = walk_pte_range_inner(pte, addr, end, walk);
                pte_unmap(pte);
        } else {
+               spinlock_t *ptl;
+
                pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
                err = walk_pte_range_inner(pte, addr, end, walk);
                pte_unmap_unlock(pte, ptl);
@@ -71,7 +70,7 @@ static int walk_hugepd_range(hugepd_t *phpd, unsigned long addr,
        if (addr & (page_size - 1))
                return 0;
 
-       for (;;) {
+       for (;; addr += page_size) {
                pte_t *pte;
                int err;
 
@@ -84,7 +83,6 @@ static int walk_hugepd_range(hugepd_t *phpd, unsigned long addr,
                        return err;
                if (addr >= end - page_size)
                        break;
-               addr += page_size;
        }
        return 0;
 }
@@ -307,14 +305,13 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end,
        unsigned long next;
        unsigned long hmask = huge_page_mask(h);
        unsigned long sz = huge_page_size(h);
-       pte_t *pte;
        const struct mm_walk_ops *ops = walk->ops;
 
-       do {
+       for (; addr < end; addr = next) {
                int err;
+               pte_t *pte = huge_pte_offset(walk->mm, addr & hmask, sz);
 
                next = hugetlb_entry_end(h, addr, end);
-               pte = huge_pte_offset(walk->mm, addr & hmask, sz);
 
                if (pte)
                        err = ops->hugetlb_entry(pte, hmask, addr, next, walk);
@@ -323,7 +320,7 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end,
 
                if (err)
                        return err;
-       } while (addr = next, addr != end);
+       }
 
        return 0;
 }
@@ -461,14 +458,13 @@ int walk_page_range(struct mm_struct *mm, unsigned long start,
        do {
                int err;
 
+               walk.vma = vma;
                if (!vma) { /* after the last vma */
-                       walk.vma = NULL;
                        next = end;
                } else if (start < vma->vm_start) { /* outside vma */
                        walk.vma = NULL;
                        next = min(end, vma->vm_start);
                } else { /* inside vma */
-                       walk.vma = vma;
                        next = min(end, vma->vm_end);
                        vma = find_vma(mm, vma->vm_end);
 
@@ -595,11 +591,11 @@ int walk_page_mapping(struct address_space *mapping, pgoff_t first_index,
        };
        struct vm_area_struct *vma;
        pgoff_t vba, vea, cba, cea;
-       unsigned long start_addr, end_addr;
 
        lockdep_assert_held(&mapping->i_mmap_rwsem);
        vma_interval_tree_foreach(vma, &mapping->i_mmap, first_index,
                                  first_index + nr - 1) {
+               unsigned long start_addr, end_addr;
                int err;
 
                /* Clip to the vma */