mm/mmap: Linked list fallout

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/mm/mmap.c b/mm/mmap.c
index d3c321796ec491566ae630c2742c50f4f30a8391..cab5192e5a12c4bb9d58254a5afb176f74ddc5fc 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2279,10 +2279,9 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 }
 
 static inline unsigned long detach_range(struct mm_struct *mm,
-                struct ma_state *src, struct ma_state *dst,
-                struct vm_area_struct *prev, struct vm_area_struct **last)
+        struct ma_state *src, struct ma_state *dst, struct vm_area_struct *vma,
+        struct vm_area_struct *prev, struct vm_area_struct **last)
 {
-       struct vm_area_struct *tmp;
        int count = 0;
        struct ma_state mas;
 
@@ -2292,28 +2291,31 @@ static inline unsigned long detach_range(struct mm_struct *mm,
         * area.
         */
        mas = *src;
-       mas_set(&mas, src->index);
-       mas_for_each(&mas, tmp, src->last) {
-               *last = tmp;
+       mas.last = src->index;
+       do {
+               BUG_ON(vma->vm_start < src->index);
+               BUG_ON(vma->vm_end > (src->last + 1));
+               *last = vma;
                count++;
-               if (tmp->vm_flags & VM_LOCKED) {
-                       mm->locked_vm -= vma_pages(tmp);
-                       munlock_vma_pages_all(tmp);
+               if (vma->vm_flags & VM_LOCKED) {
+                       mm->locked_vm -= vma_pages(vma);
+                       munlock_vma_pages_all(vma);
                }
-               vma_mas_store(tmp, dst);
-       }
+               vma_mas_store(vma, dst);
+       } while ((vma = mas_find(&mas, src->last)) != NULL);
 
-       /* Decrement map_count */
-       mm->map_count -= count;
        /* Find the one after the series before overwrite */
-       tmp = mas_find(&mas, ULONG_MAX);
+       mas.index = mas.last = src->last + 1;
+       vma = mas_find(&mas, -1);
        /* Drop removed area from the tree */
        mas_store_gfp(src, NULL, GFP_KERNEL);
+       /* Decrement map_count */
+       mm->map_count -= count;
        /* Set the upper limit */
-       if (!tmp)
+       if (!vma)
                return USER_PGTABLES_CEILING;
 
-       return tmp->vm_start;
+       return vma->vm_start;
 }
 
 /* do_mas_align_munmap() - munmap the aligned region from @start to @end.
@@ -2361,9 +2363,7 @@ int do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
                        return error;
                prev = vma;
                // Split invalidated node, reset.
-               mas->index = start;
-               mas_reset(mas);
-               vma = mas_walk(mas);
+               mas_set_range(mas, start, end - 1);
        } else {
                tmp = *mas;
                prev = mas_prev(&tmp, 0);
@@ -2373,7 +2373,6 @@ int do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
                last = vma;
        else {
                tmp = *mas;
-               mas_reset(&tmp);
                mas_set(&tmp, end - 1);
                last = mas_walk(&tmp);
        }
@@ -2384,11 +2383,12 @@ int do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
                if (error)
                        return error;
                // Split invalidated node, reset.
-               mas->index = start;
-               mas_reset(mas);
-               vma = mas_walk(mas);
+               mas_set_range(mas, start, end - 1);
+
        }
 
+       if (mas->node == MAS_START)
+               vma = mas_walk(mas);
 
        if (unlikely(uf)) {
                /*
@@ -2407,7 +2407,7 @@ int do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
        }
 
        /* Point of no return */
-       max = detach_range(mm, mas, &dst, prev, &last);
+       max = detach_range(mm, mas, &dst, vma, prev, &last);
 
        /*
         * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or
@@ -2423,14 +2423,14 @@ int do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
                        mmap_write_downgrade(mm);
        }
 
-       mas_reset(&dst);
+       /* Unmap the region */
        mas_set(&dst, start);
+       tmp = dst;
        vma = mas_walk(&dst);
        unmap_region(mm, vma, &dst, start, end, prev, max);
 
-       /* Fix up all other VM information */
-       mas_reset(&dst);
-       mas_set(&dst, start);
+       /* Statistics and freeing VMAs */
+       dst = tmp;
        remove_mt(mm, &dst);
 
        return downgrade ? 1 : 0;
@@ -2457,7 +2457,8 @@ int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
        unsigned long end;
        struct vm_area_struct *vma;
 
-       if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start)
+       if ((offset_in_page(start)) || (start > TASK_SIZE) ||
+           (len > TASK_SIZE - start))
                return -EINVAL;
 
        end = start + PAGE_ALIGN(len);
@@ -2472,8 +2473,7 @@ int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
        if (!vma)
                return 0;
 
-//     printk("vma found at %lx %lu\n", vma->vm_start, vma->vm_end);
-       mas_set_range(mas, start, end - 1);
+       mas->last = end - 1;
        return do_mas_align_munmap(mas, vma, mm, start, end, uf, downgrade);
 }
 /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls.
@@ -2535,7 +2535,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
                vm_flags |= VM_ACCOUNT;
        }
 
-       mas_reset(&mas);
        mas_set_range(&mas, addr, end - 1);
        if (vm_flags & VM_SPECIAL) {
                ma_prev = mas;
@@ -2675,7 +2674,8 @@ cannot_expand:
 
        // Very likely a shorter walk.
        mas = ma_prev;
-       mas_set_range(&mas, addr, end - 1);
+       mas.last = end - 1;
+       mas.index = addr;
        mas_walk(&mas);
        vma_mas_link(mm, vma, &mas);
 
@@ -2888,6 +2888,7 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
        arch_unmap(mm, newbrk, oldbrk);
 
        if (likely(vma->vm_start >= newbrk)) { // remove entire mapping(s)
+               mas->last = oldbrk - 1;
                ret = do_mas_align_munmap(mas, vma, mm, newbrk, oldbrk, uf, true);
                goto munmap_full_vma;
        }
@@ -3135,7 +3136,6 @@ void exit_mmap(struct mm_struct *mm)
                                munlock_vma_pages_all(vma);
                        }
                }
-               mas_reset(&mas);
                mas_set(&mas, FIRST_USER_ADDRESS);
        }
 
@@ -3146,7 +3146,6 @@ void exit_mmap(struct mm_struct *mm)
                return;
 
        mas2 = mas;
-       mas_reset(&mas);
        mas_set(&mas, FIRST_USER_ADDRESS);
 
        lru_add_drain();
@@ -3162,7 +3161,6 @@ void exit_mmap(struct mm_struct *mm)
         * Walk the list again, actually closing and freeing it,
         * with preemption enabled, without holding any MM locks.
         */
-       mas_reset(&mas);
        mas_set(&mas, 0);
        mas_for_each(&mas, vma, -1) {
                if (vma->vm_flags & VM_ACCOUNT)
@@ -3573,7 +3571,6 @@ int mm_take_all_locks(struct mm_struct *mm)
                        vm_lock_mapping(mm, vma->vm_file->f_mapping);
        }
 
-       mas_reset(&mas);
        mas_set(&mas, 0);
        mas_for_each(&mas, vma, ULONG_MAX) {
                if (signal_pending(current))
@@ -3583,7 +3580,6 @@ int mm_take_all_locks(struct mm_struct *mm)
                        vm_lock_mapping(mm, vma->vm_file->f_mapping);
        }
 
-       mas_reset(&mas);
        mas_set(&mas, 0);
        mas_for_each(&mas, vma, ULONG_MAX) {
                if (signal_pending(current))