mm: remove rb tree.
authorLiam R. Howlett <Liam.Howlett@Oracle.com>
Tue, 6 Sep 2022 19:48:48 +0000 (19:48 +0000)
committerAndrew Morton <akpm@linux-foundation.org>
Tue, 27 Sep 2022 02:46:16 +0000 (19:46 -0700)
Remove the RB tree and start using the maple tree for vm_area_struct
tracking.

Drop validate_mm() calls in expand_upwards() and expand_downwards() as the
lock is not held.

Link: https://lkml.kernel.org/r/20220906194824.2110408-18-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
arch/x86/kernel/tboot.c
drivers/firmware/efi/efi.c
include/linux/mm.h
include/linux/mm_types.h
kernel/fork.c
mm/init-mm.c
mm/mmap.c
mm/nommu.c
mm/util.c

index e015442..4c1bcb6 100644 (file)
@@ -95,7 +95,6 @@ void __init tboot_probe(void)
 
 static pgd_t *tboot_pg_dir;
 static struct mm_struct tboot_mm = {
-       .mm_rb          = RB_ROOT,
        .mm_mt          = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, tboot_mm.mmap_lock),
        .pgd            = swapper_pg_dir,
        .mm_users       = ATOMIC_INIT(2),
index 7b6a815..042a3ef 100644 (file)
@@ -57,7 +57,6 @@ static unsigned long __initdata mem_reserve = EFI_INVALID_TABLE_ADDR;
 static unsigned long __initdata rt_prop = EFI_INVALID_TABLE_ADDR;
 
 struct mm_struct efi_mm = {
-       .mm_rb                  = RB_ROOT,
        .mm_mt                  = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, efi_mm.mmap_lock),
        .mm_users               = ATOMIC_INIT(2),
        .mm_count               = ATOMIC_INIT(1),
index 646ea4d..dfce1aa 100644 (file)
@@ -2654,8 +2654,6 @@ extern int __split_vma(struct mm_struct *, struct vm_area_struct *,
 extern int split_vma(struct mm_struct *, struct vm_area_struct *,
        unsigned long addr, int new_below);
 extern int insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
-extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
-       struct rb_node **, struct rb_node *);
 extern void unlink_file_vma(struct vm_area_struct *);
 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
        unsigned long addr, unsigned long len, pgoff_t pgoff,
index d0b51fb..ac74727 100644 (file)
@@ -410,19 +410,6 @@ struct vm_area_struct {
 
        /* linked list of VM areas per task, sorted by address */
        struct vm_area_struct *vm_next, *vm_prev;
-
-       struct rb_node vm_rb;
-
-       /*
-        * Largest free memory gap in bytes to the left of this VMA.
-        * Either between this VMA and vma->vm_prev, or between one of the
-        * VMAs below us in the VMA rbtree and its ->vm_prev. This helps
-        * get_unmapped_area find a free area of the right size.
-        */
-       unsigned long rb_subtree_gap;
-
-       /* Second cache line starts here. */
-
        struct mm_struct *vm_mm;        /* The address space we belong to. */
 
        /*
@@ -488,7 +475,6 @@ struct mm_struct {
        struct {
                struct vm_area_struct *mmap;            /* list of VMAs */
                struct maple_tree mm_mt;
-               struct rb_root mm_rb;
                u64 vmacache_seqnum;                   /* per-thread vmacache */
 #ifdef CONFIG_MMU
                unsigned long (*get_unmapped_area) (struct file *filp,
index 16970c3..5f81c00 100644 (file)
@@ -581,7 +581,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
                                        struct mm_struct *oldmm)
 {
        struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
-       struct rb_node **rb_link, *rb_parent;
        int retval;
        unsigned long charge = 0;
        LIST_HEAD(uf);
@@ -608,8 +607,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
        mm->exec_vm = oldmm->exec_vm;
        mm->stack_vm = oldmm->stack_vm;
 
-       rb_link = &mm->mm_rb.rb_node;
-       rb_parent = NULL;
        pprev = &mm->mmap;
        retval = ksm_fork(mm, oldmm);
        if (retval)
@@ -701,10 +698,6 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
                tmp->vm_prev = prev;
                prev = tmp;
 
-               __vma_link_rb(mm, tmp, rb_link, rb_parent);
-               rb_link = &tmp->vm_rb.rb_right;
-               rb_parent = &tmp->vm_rb;
-
                /* Link the vma into the MT */
                mas.index = tmp->vm_start;
                mas.last = tmp->vm_end - 1;
@@ -1133,7 +1126,6 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
        struct user_namespace *user_ns)
 {
        mm->mmap = NULL;
-       mm->mm_rb = RB_ROOT;
        mt_init_flags(&mm->mm_mt, MM_MT_FLAGS);
        mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock);
        mm->vmacache_seqnum = 0;
index b912b0f..c9327ab 100644 (file)
@@ -1,6 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/mm_types.h>
-#include <linux/rbtree.h>
 #include <linux/maple_tree.h>
 #include <linux/rwsem.h>
 #include <linux/spinlock.h>
@@ -29,7 +28,6 @@
  * and size this cpu_bitmask to NR_CPUS.
  */
 struct mm_struct init_mm = {
-       .mm_rb          = RB_ROOT,
        .mm_mt          = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, init_mm.mmap_lock),
        .pgd            = swapper_pg_dir,
        .mm_users       = ATOMIC_INIT(2),
index 68ee295..f60d83c 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -39,7 +39,6 @@
 #include <linux/audit.h>
 #include <linux/khugepaged.h>
 #include <linux/uprobes.h>
-#include <linux/rbtree_augmented.h>
 #include <linux/notifier.h>
 #include <linux/memory.h>
 #include <linux/printk.h>
@@ -247,93 +246,6 @@ out:
        return origbrk;
 }
 
-static inline unsigned long vma_compute_gap(struct vm_area_struct *vma)
-{
-       unsigned long gap, prev_end;
-
-       /*
-        * Note: in the rare case of a VM_GROWSDOWN above a VM_GROWSUP, we
-        * allow two stack_guard_gaps between them here, and when choosing
-        * an unmapped area; whereas when expanding we only require one.
-        * That's a little inconsistent, but keeps the code here simpler.
-        */
-       gap = vm_start_gap(vma);
-       if (vma->vm_prev) {
-               prev_end = vm_end_gap(vma->vm_prev);
-               if (gap > prev_end)
-                       gap -= prev_end;
-               else
-                       gap = 0;
-       }
-       return gap;
-}
-
-#ifdef CONFIG_DEBUG_VM_RB
-static unsigned long vma_compute_subtree_gap(struct vm_area_struct *vma)
-{
-       unsigned long max = vma_compute_gap(vma), subtree_gap;
-       if (vma->vm_rb.rb_left) {
-               subtree_gap = rb_entry(vma->vm_rb.rb_left,
-                               struct vm_area_struct, vm_rb)->rb_subtree_gap;
-               if (subtree_gap > max)
-                       max = subtree_gap;
-       }
-       if (vma->vm_rb.rb_right) {
-               subtree_gap = rb_entry(vma->vm_rb.rb_right,
-                               struct vm_area_struct, vm_rb)->rb_subtree_gap;
-               if (subtree_gap > max)
-                       max = subtree_gap;
-       }
-       return max;
-}
-
-static int browse_rb(struct mm_struct *mm)
-{
-       struct rb_root *root = &mm->mm_rb;
-       int i = 0, j, bug = 0;
-       struct rb_node *nd, *pn = NULL;
-       unsigned long prev = 0, pend = 0;
-
-       for (nd = rb_first(root); nd; nd = rb_next(nd)) {
-               struct vm_area_struct *vma;
-               vma = rb_entry(nd, struct vm_area_struct, vm_rb);
-               if (vma->vm_start < prev) {
-                       pr_emerg("vm_start %lx < prev %lx\n",
-                                 vma->vm_start, prev);
-                       bug = 1;
-               }
-               if (vma->vm_start < pend) {
-                       pr_emerg("vm_start %lx < pend %lx\n",
-                                 vma->vm_start, pend);
-                       bug = 1;
-               }
-               if (vma->vm_start > vma->vm_end) {
-                       pr_emerg("vm_start %lx > vm_end %lx\n",
-                                 vma->vm_start, vma->vm_end);
-                       bug = 1;
-               }
-               spin_lock(&mm->page_table_lock);
-               if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
-                       pr_emerg("free gap %lx, correct %lx\n",
-                              vma->rb_subtree_gap,
-                              vma_compute_subtree_gap(vma));
-                       bug = 1;
-               }
-               spin_unlock(&mm->page_table_lock);
-               i++;
-               pn = nd;
-               prev = vma->vm_start;
-               pend = vma->vm_end;
-       }
-       j = 0;
-       for (nd = pn; nd; nd = rb_prev(nd))
-               j++;
-       if (i != j) {
-               pr_emerg("backwards %d, forwards %d\n", j, i);
-               bug = 1;
-       }
-       return bug ? -1 : i;
-}
 #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
 extern void mt_validate(struct maple_tree *mt);
 extern void mt_dump(const struct maple_tree *mt);
@@ -361,19 +273,25 @@ static void validate_mm_mt(struct mm_struct *mm)
                    (vma->vm_end - 1 != mas.last)) {
                        pr_emerg("issue in %s\n", current->comm);
                        dump_stack();
-#ifdef CONFIG_DEBUG_VM
                        dump_vma(vma_mt);
-                       pr_emerg("and next in rb\n");
+                       pr_emerg("and vm_next\n");
                        dump_vma(vma->vm_next);
-#endif
                        pr_emerg("mt piv: %p %lu - %lu\n", vma_mt,
                                 mas.index, mas.last);
                        pr_emerg("mt vma: %p %lu - %lu\n", vma_mt,
                                 vma_mt->vm_start, vma_mt->vm_end);
-                       pr_emerg("rb vma: %p %lu - %lu\n", vma,
+                       if (vma->vm_prev) {
+                               pr_emerg("ll prev: %p %lu - %lu\n",
+                                        vma->vm_prev, vma->vm_prev->vm_start,
+                                        vma->vm_prev->vm_end);
+                       }
+                       pr_emerg("ll vma: %p %lu - %lu\n", vma,
                                 vma->vm_start, vma->vm_end);
-                       pr_emerg("rb->next = %p %lu - %lu\n", vma->vm_next,
-                                       vma->vm_next->vm_start, vma->vm_next->vm_end);
+                       if (vma->vm_next) {
+                               pr_emerg("ll next: %p %lu - %lu\n",
+                                        vma->vm_next, vma->vm_next->vm_start,
+                                        vma->vm_next->vm_end);
+                       }
 
                        mt_dump(mas.tree);
                        if (vma_mt->vm_end != mas.last + 1) {
@@ -396,21 +314,6 @@ static void validate_mm_mt(struct mm_struct *mm)
        }
        VM_BUG_ON(vma);
 }
-#else
-#define validate_mm_mt(root) do { } while (0)
-#endif
-static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore)
-{
-       struct rb_node *nd;
-
-       for (nd = rb_first(root); nd; nd = rb_next(nd)) {
-               struct vm_area_struct *vma;
-               vma = rb_entry(nd, struct vm_area_struct, vm_rb);
-               VM_BUG_ON_VMA(vma != ignore &&
-                       vma->rb_subtree_gap != vma_compute_subtree_gap(vma),
-                       vma);
-       }
-}
 
 static void validate_mm(struct mm_struct *mm)
 {
@@ -419,7 +322,10 @@ static void validate_mm(struct mm_struct *mm)
        unsigned long highest_address = 0;
        struct vm_area_struct *vma = mm->mmap;
 
+       validate_mm_mt(mm);
+
        while (vma) {
+#ifdef CONFIG_DEBUG_VM_RB
                struct anon_vma *anon_vma = vma->anon_vma;
                struct anon_vma_chain *avc;
 
@@ -429,6 +335,7 @@ static void validate_mm(struct mm_struct *mm)
                                anon_vma_interval_tree_verify(avc);
                        anon_vma_unlock_read(anon_vma);
                }
+#endif
 
                highest_address = vm_end_gap(vma);
                vma = vma->vm_next;
@@ -443,80 +350,13 @@ static void validate_mm(struct mm_struct *mm)
                          mm->highest_vm_end, highest_address);
                bug = 1;
        }
-       i = browse_rb(mm);
-       if (i != mm->map_count) {
-               if (i != -1)
-                       pr_emerg("map_count %d rb %d\n", mm->map_count, i);
-               bug = 1;
-       }
        VM_BUG_ON_MM(bug, mm);
 }
-#else
-#define validate_mm_rb(root, ignore) do { } while (0)
+
+#else /* !CONFIG_DEBUG_VM_MAPLE_TREE */
 #define validate_mm_mt(root) do { } while (0)
 #define validate_mm(mm) do { } while (0)
-#endif
-
-RB_DECLARE_CALLBACKS_MAX(static, vma_gap_callbacks,
-                        struct vm_area_struct, vm_rb,
-                        unsigned long, rb_subtree_gap, vma_compute_gap)
-
-/*
- * Update augmented rbtree rb_subtree_gap values after vma->vm_start or
- * vma->vm_prev->vm_end values changed, without modifying the vma's position
- * in the rbtree.
- */
-static void vma_gap_update(struct vm_area_struct *vma)
-{
-       /*
-        * As it turns out, RB_DECLARE_CALLBACKS_MAX() already created
-        * a callback function that does exactly what we want.
-        */
-       vma_gap_callbacks_propagate(&vma->vm_rb, NULL);
-}
-
-static inline void vma_rb_insert(struct vm_area_struct *vma,
-                                struct rb_root *root)
-{
-       /* All rb_subtree_gap values must be consistent prior to insertion */
-       validate_mm_rb(root, NULL);
-
-       rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
-}
-
-static void __vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root)
-{
-       /*
-        * Note rb_erase_augmented is a fairly large inline function,
-        * so make sure we instantiate it only once with our desired
-        * augmented rbtree callbacks.
-        */
-       rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks);
-}
-
-static __always_inline void vma_rb_erase_ignore(struct vm_area_struct *vma,
-                                               struct rb_root *root,
-                                               struct vm_area_struct *ignore)
-{
-       /*
-        * All rb_subtree_gap values must be consistent prior to erase,
-        * with the possible exception of
-        *
-        * a. the "next" vma being erased if next->vm_start was reduced in
-        *    __vma_adjust() -> __vma_unlink()
-        * b. the vma being erased in detach_vmas_to_be_unmapped() ->
-        *    vma_rb_erase()
-        */
-       validate_mm_rb(root, ignore);
-
-       __vma_rb_erase(vma, root);
-}
-
-static __always_inline void vma_rb_erase(struct vm_area_struct *vma,
-                                        struct rb_root *root)
-{
-       vma_rb_erase_ignore(vma, root, vma);
-}
+#endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
 
 /*
  * vma has some anon_vma assigned, and is already inserted on that
@@ -550,39 +390,26 @@ anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma)
                anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root);
 }
 
-static int find_vma_links(struct mm_struct *mm, unsigned long addr,
-               unsigned long end, struct vm_area_struct **pprev,
-               struct rb_node ***rb_link, struct rb_node **rb_parent)
+/*
+ * range_has_overlap() - Check the @start - @end range for overlapping VMAs and
+ * sets up a pointer to the previous VMA
+ * @mm: the mm struct
+ * @start: the start address of the range
+ * @end: the end address of the range
+ * @pprev: the pointer to the pointer of the previous VMA
+ *
+ * Returns: True if there is an overlapping VMA, false otherwise
+ */
+static inline
+bool range_has_overlap(struct mm_struct *mm, unsigned long start,
+                      unsigned long end, struct vm_area_struct **pprev)
 {
-       struct rb_node **__rb_link, *__rb_parent, *rb_prev;
-
-       mmap_assert_locked(mm);
-       __rb_link = &mm->mm_rb.rb_node;
-       rb_prev = __rb_parent = NULL;
-
-       while (*__rb_link) {
-               struct vm_area_struct *vma_tmp;
-
-               __rb_parent = *__rb_link;
-               vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
+       struct vm_area_struct *existing;
 
-               if (vma_tmp->vm_end > addr) {
-                       /* Fail if an existing vma overlaps the area */
-                       if (vma_tmp->vm_start < end)
-                               return -ENOMEM;
-                       __rb_link = &__rb_parent->rb_left;
-               } else {
-                       rb_prev = __rb_parent;
-                       __rb_link = &__rb_parent->rb_right;
-               }
-       }
-
-       *pprev = NULL;
-       if (rb_prev)
-               *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
-       *rb_link = __rb_link;
-       *rb_parent = __rb_parent;
-       return 0;
+       MA_STATE(mas, &mm->mm_mt, start, start);
+       existing = mas_find(&mas, end - 1);
+       *pprev = mas_prev(&mas, 0);
+       return existing ? true : false;
 }
 
 /*
@@ -609,8 +436,6 @@ static inline struct vm_area_struct *__vma_next(struct mm_struct *mm,
  * @start: The start of the range.
  * @len: The length of the range.
  * @pprev: pointer to the pointer that will be set to previous vm_area_struct
- * @rb_link: the rb_node
- * @rb_parent: the parent rb_node
  *
  * Find all the vm_area_struct that overlap from @start to
  * @end and munmap them.  Set @pprev to the previous vm_area_struct.
@@ -619,14 +444,11 @@ static inline struct vm_area_struct *__vma_next(struct mm_struct *mm,
  */
 static inline int
 munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
-                struct vm_area_struct **pprev, struct rb_node ***link,
-                struct rb_node **parent, struct list_head *uf)
+                struct vm_area_struct **pprev, struct list_head *uf)
 {
-
-       while (find_vma_links(mm, start, start + len, pprev, link, parent))
+       while (range_has_overlap(mm, start, start + len, pprev))
                if (do_munmap(mm, start, len, uf))
                        return -ENOMEM;
-
        return 0;
 }
 
@@ -647,30 +469,6 @@ static unsigned long count_vma_pages_range(struct mm_struct *mm,
        return nr_pages;
 }
 
-void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
-               struct rb_node **rb_link, struct rb_node *rb_parent)
-{
-       /* Update tracking information for the gap following the new vma. */
-       if (vma->vm_next)
-               vma_gap_update(vma->vm_next);
-       else
-               mm->highest_vm_end = vm_end_gap(vma);
-
-       /*
-        * vma->vm_prev wasn't known when we followed the rbtree to find the
-        * correct insertion point for that vma. As a result, we could not
-        * update the vma vm_rb parents rb_subtree_gap values on the way down.
-        * So, we first insert the vma with a zero rb_subtree_gap value
-        * (to be consistent with what we did on the way down), and then
-        * immediately update the gap to the correct value. Finally we
-        * rebalance the rbtree after all augmented values have been set.
-        */
-       rb_link_node(&vma->vm_rb, rb_parent, rb_link);
-       vma->rb_subtree_gap = 0;
-       vma_gap_update(vma);
-       vma_rb_insert(vma, &mm->mm_rb);
-}
-
 static void __vma_link_file(struct vm_area_struct *vma)
 {
        struct file *file;
@@ -738,18 +536,8 @@ static inline void vma_mas_szero(struct ma_state *mas, unsigned long start,
        mas_store_prealloc(mas, NULL);
 }
 
-static void
-__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
-       struct vm_area_struct *prev, struct rb_node **rb_link,
-       struct rb_node *rb_parent)
-{
-       __vma_link_list(mm, vma, prev);
-       __vma_link_rb(mm, vma, rb_link, rb_parent);
-}
-
 static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
-                       struct vm_area_struct *prev, struct rb_node **rb_link,
-                       struct rb_node *rb_parent)
+                       struct vm_area_struct *prev)
 {
        MA_STATE(mas, &mm->mm_mt, 0, 0);
        struct address_space *mapping = NULL;
@@ -763,7 +551,7 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
        }
 
        vma_mas_store(vma, &mas);
-       __vma_link(mm, vma, prev, rb_link, rb_parent);
+       __vma_link_list(mm, vma, prev);
        __vma_link_file(vma);
 
        if (mapping)
@@ -776,34 +564,20 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
 
 /*
  * Helper for vma_adjust() in the split_vma insert case: insert a vma into the
- * mm's list and rbtree.  It has already been inserted into the interval tree.
+ * mm's list and the mm tree.  It has already been inserted into the interval tree.
  */
 static void __insert_vm_struct(struct mm_struct *mm, struct ma_state *mas,
                               struct vm_area_struct *vma)
 {
        struct vm_area_struct *prev;
-       struct rb_node **rb_link, *rb_parent;
-
-       if (find_vma_links(mm, vma->vm_start, vma->vm_end,
-                          &prev, &rb_link, &rb_parent))
-               BUG();
 
+       mas_set(mas, vma->vm_start);
+       prev = mas_prev(mas, 0);
        vma_mas_store(vma, mas);
        __vma_link_list(mm, vma, prev);
-       __vma_link_rb(mm, vma, rb_link, rb_parent);
        mm->map_count++;
 }
 
-static __always_inline void __vma_unlink(struct mm_struct *mm,
-                                               struct vm_area_struct *vma,
-                                               struct vm_area_struct *ignore)
-{
-       vma_rb_erase_ignore(vma, &mm->mm_rb, ignore);
-       __vma_unlink_list(mm, vma);
-       /* Kill the cache */
-       vmacache_invalidate(mm);
-}
-
 /*
  * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
  * is already present in an i_mmap tree without adjusting the tree.
@@ -816,21 +590,18 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
        struct vm_area_struct *expand)
 {
        struct mm_struct *mm = vma->vm_mm;
-       struct vm_area_struct *next = vma->vm_next, *orig_vma = vma;
-       struct vm_area_struct *next_next;
+       struct vm_area_struct *next_next, *next = find_vma(mm, vma->vm_end);
+       struct vm_area_struct *orig_vma = vma;
        struct address_space *mapping = NULL;
        struct rb_root_cached *root = NULL;
        struct anon_vma *anon_vma = NULL;
        struct file *file = vma->vm_file;
-       bool start_changed = false, end_changed = false;
+       bool vma_changed = false;
        long adjust_next = 0;
        int remove_next = 0;
        MA_STATE(mas, &mm->mm_mt, 0, 0);
        struct vm_area_struct *exporter = NULL, *importer = NULL;
 
-       validate_mm(mm);
-       validate_mm_mt(mm);
-
        if (next && !insert) {
                if (end >= next->vm_end) {
                        /*
@@ -957,21 +728,21 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
        }
 
        if (start != vma->vm_start) {
-               unsigned long old_start = vma->vm_start;
+               if (vma->vm_start < start)
+                       vma_mas_szero(&mas, vma->vm_start, start);
+               vma_changed = true;
                vma->vm_start = start;
-               if (old_start < start)
-                       vma_mas_szero(&mas, old_start, start);
-               start_changed = true;
        }
        if (end != vma->vm_end) {
-               unsigned long old_end = vma->vm_end;
+               if (vma->vm_end > end)
+                       vma_mas_szero(&mas, end, vma->vm_end);
+               vma_changed = true;
                vma->vm_end = end;
-               if (old_end > end)
-                       vma_mas_szero(&mas, end, old_end);
-               end_changed = true;
+               if (!next)
+                       mm->highest_vm_end = vm_end_gap(vma);
        }
 
-       if (end_changed || start_changed)
+       if (vma_changed)
                vma_mas_store(vma, &mas);
 
        vma->vm_pgoff = pgoff;
@@ -995,22 +766,12 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
                 * Since we have expanded over this vma, the maple tree will
                 * have overwritten by storing the value
                 */
-               if (remove_next != 3) {
-                       __vma_unlink(mm, next, next);
-                       if (remove_next == 2)
-                               __vma_unlink(mm, next_next, next_next);
-               } else {
-                       /*
-                        * vma is not before next if they've been
-                        * swapped.
-                        *
-                        * pre-swap() next->vm_start was reduced so
-                        * tell validate_mm_rb to ignore pre-swap()
-                        * "next" (which is stored in post-swap()
-                        * "vma").
-                        */
-                       __vma_unlink(mm, next, vma);
-               }
+               __vma_unlink_list(mm, next);
+               if (remove_next == 2)
+                       __vma_unlink_list(mm, next_next);
+               /* Kill the cache */
+               vmacache_invalidate(mm);
+
                if (file) {
                        __remove_shared_vm_struct(next, file, mapping);
                        if (remove_next == 2)
@@ -1023,15 +784,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
                 * (it may either follow vma or precede it).
                 */
                __insert_vm_struct(mm, &mas, insert);
-       } else {
-               if (start_changed)
-                       vma_gap_update(vma);
-               if (end_changed) {
-                       if (!next)
-                               mm->highest_vm_end = vm_end_gap(vma);
-                       else if (!adjust_next)
-                               vma_gap_update(next);
-               }
        }
 
        if (anon_vma) {
@@ -1059,7 +811,10 @@ again:
                        anon_vma_merge(vma, next);
                mm->map_count--;
                mpol_put(vma_policy(next));
+               if (remove_next != 2)
+                       BUG_ON(vma->vm_end < next->vm_end);
                vm_area_free(next);
+
                /*
                 * In mprotect's case 6 (see comments on vma_merge),
                 * we must remove another next too. It would clutter
@@ -1089,10 +844,7 @@ again:
                if (remove_next == 2) {
                        remove_next = 1;
                        goto again;
-               }
-               else if (next)
-                       vma_gap_update(next);
-               else {
+               } else if (!next) {
                        /*
                         * If remove_next == 2 we obviously can't
                         * reach this path.
@@ -1119,8 +871,6 @@ again:
                uprobe_mmap(insert);
 
        validate_mm(mm);
-       validate_mm_mt(mm);
-
        return 0;
 }
 
@@ -1273,7 +1023,6 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
        struct vm_area_struct *area, *next;
        int err;
 
-       validate_mm_mt(mm);
        /*
         * We later require that vma->vm_flags == vm_flags,
         * so this tests vma->vm_flags & VM_SPECIAL, too.
@@ -1349,7 +1098,6 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
                khugepaged_enter_vma(area, vm_flags);
                return area;
        }
-       validate_mm_mt(mm);
 
        return NULL;
 }
@@ -1519,6 +1267,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
        vm_flags_t vm_flags;
        int pkey = 0;
 
+       validate_mm(mm);
        *populate = 0;
 
        if (!len)
@@ -1829,10 +1578,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma, *prev, *merge;
        int error;
-       struct rb_node **rb_link, *rb_parent;
        unsigned long charged = 0;
 
-       validate_mm_mt(mm);
        /* Check against address space limit. */
        if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) {
                unsigned long nr_pages;
@@ -1848,8 +1595,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
                        return -ENOMEM;
        }
 
-       /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
-       if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+       /* Clear old maps, set up prev and uf */
+       if (munmap_vma_range(mm, addr, len, &prev, uf))
                return -ENOMEM;
        /*
         * Private writable mapping: check memory availability
@@ -1947,7 +1694,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
                        goto free_vma;
        }
 
-       if (vma_link(mm, vma, prev, rb_link, rb_parent)) {
+       if (vma_link(mm, vma, prev)) {
                error = -ENOMEM;
                if (file)
                        goto unmap_and_free_vma;
@@ -1993,7 +1740,6 @@ out:
 
        vma_set_page_prot(vma);
 
-       validate_mm_mt(mm);
        return addr;
 
 unmap_and_free_vma:
@@ -2009,7 +1755,6 @@ free_vma:
 unacct_error:
        if (charged)
                vm_unacct_memory(charged);
-       validate_mm_mt(mm);
        return error;
 }
 
@@ -2367,7 +2112,6 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
        int error = 0;
        MA_STATE(mas, &mm->mm_mt, 0, 0);
 
-       validate_mm_mt(mm);
        if (!(vma->vm_flags & VM_GROWSUP))
                return -EFAULT;
 
@@ -2419,15 +2163,13 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                        error = acct_stack_growth(vma, size, grow);
                        if (!error) {
                                /*
-                                * vma_gap_update() doesn't support concurrent
-                                * updates, but we only hold a shared mmap_lock
-                                * lock here, so we need to protect against
-                                * concurrent vma expansions.
-                                * anon_vma_lock_write() doesn't help here, as
-                                * we don't guarantee that all growable vmas
-                                * in a mm share the same root anon vma.
-                                * So, we reuse mm->page_table_lock to guard
-                                * against concurrent vma expansions.
+                                * We only hold a shared mmap_lock lock here, so
+                                * we need to protect against concurrent vma
+                                * expansions.  anon_vma_lock_write() doesn't
+                                * help here, as we don't guarantee that all
+                                * growable vmas in a mm share the same root
+                                * anon vma.  So, we reuse mm->page_table_lock
+                                * to guard against concurrent vma expansions.
                                 */
                                spin_lock(&mm->page_table_lock);
                                if (vma->vm_flags & VM_LOCKED)
@@ -2438,9 +2180,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                                /* Overwrite old entry in mtree. */
                                vma_mas_store(vma, &mas);
                                anon_vma_interval_tree_post_update_vma(vma);
-                               if (vma->vm_next)
-                                       vma_gap_update(vma->vm_next);
-                               else
+                               if (!vma->vm_next)
                                        mm->highest_vm_end = vm_end_gap(vma);
                                spin_unlock(&mm->page_table_lock);
 
@@ -2450,8 +2190,6 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
        }
        anon_vma_unlock_write(vma->anon_vma);
        khugepaged_enter_vma(vma, vma->vm_flags);
-       validate_mm(mm);
-       validate_mm_mt(mm);
        mas_destroy(&mas);
        return error;
 }
@@ -2460,15 +2198,13 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 /*
  * vma is the first one with address < vma->vm_start.  Have to extend vma.
  */
-int expand_downwards(struct vm_area_struct *vma,
-                                  unsigned long address)
+int expand_downwards(struct vm_area_struct *vma, unsigned long address)
 {
        struct mm_struct *mm = vma->vm_mm;
        struct vm_area_struct *prev;
        int error = 0;
        MA_STATE(mas, &mm->mm_mt, 0, 0);
 
-       validate_mm(mm);
        address &= PAGE_MASK;
        if (address < mmap_min_addr)
                return -EPERM;
@@ -2510,15 +2246,13 @@ int expand_downwards(struct vm_area_struct *vma,
                        error = acct_stack_growth(vma, size, grow);
                        if (!error) {
                                /*
-                                * vma_gap_update() doesn't support concurrent
-                                * updates, but we only hold a shared mmap_lock
-                                * lock here, so we need to protect against
-                                * concurrent vma expansions.
-                                * anon_vma_lock_write() doesn't help here, as
-                                * we don't guarantee that all growable vmas
-                                * in a mm share the same root anon vma.
-                                * So, we reuse mm->page_table_lock to guard
-                                * against concurrent vma expansions.
+                                * We only hold a shared mmap_lock lock here, so
+                                * we need to protect against concurrent vma
+                                * expansions.  anon_vma_lock_write() doesn't
+                                * help here, as we don't guarantee that all
+                                * growable vmas in a mm share the same root
+                                * anon vma.  So, we reuse mm->page_table_lock
+                                * to guard against concurrent vma expansions.
                                 */
                                spin_lock(&mm->page_table_lock);
                                if (vma->vm_flags & VM_LOCKED)
@@ -2530,7 +2264,6 @@ int expand_downwards(struct vm_area_struct *vma,
                                /* Overwrite old entry in mtree. */
                                vma_mas_store(vma, &mas);
                                anon_vma_interval_tree_post_update_vma(vma);
-                               vma_gap_update(vma);
                                spin_unlock(&mm->page_table_lock);
 
                                perf_event_mmap(vma);
@@ -2539,7 +2272,6 @@ int expand_downwards(struct vm_area_struct *vma,
        }
        anon_vma_unlock_write(vma->anon_vma);
        khugepaged_enter_vma(vma, vma->vm_flags);
-       validate_mm(mm);
        mas_destroy(&mas);
        return error;
 }
@@ -2671,10 +2403,8 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct ma_state *mas,
 
        insertion_point = (prev ? &prev->vm_next : &mm->mmap);
        vma->vm_prev = NULL;
-       mas_set_range(mas, vma->vm_start, end - 1);
-       mas_store_prealloc(mas, NULL);
+       vma_mas_szero(mas, vma->vm_start, end);
        do {
-               vma_rb_erase(vma, &mm->mm_rb);
                if (vma->vm_flags & VM_LOCKED)
                        mm->locked_vm -= vma_pages(vma);
                mm->map_count--;
@@ -2682,10 +2412,9 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct ma_state *mas,
                vma = vma->vm_next;
        } while (vma && vma->vm_start < end);
        *insertion_point = vma;
-       if (vma) {
+       if (vma)
                vma->vm_prev = prev;
-               vma_gap_update(vma);
-       } else
+       else
                mm->highest_vm_end = prev ? vm_end_gap(prev) : 0;
        tail_vma->vm_next = NULL;
 
@@ -2807,11 +2536,7 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
        if (len == 0)
                return -EINVAL;
 
-       /*
-        * arch_unmap() might do unmaps itself.  It must be called
-        * and finish any rbtree manipulation before this code
-        * runs and also starts to manipulate the rbtree.
-        */
+        /* arch_unmap() might do unmaps itself.  */
        arch_unmap(mm, start, end);
 
        /* Find the first overlapping VMA where start < vma->vm_end */
@@ -2822,6 +2547,11 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
        if (mas_preallocate(&mas, vma, GFP_KERNEL))
                return -ENOMEM;
        prev = vma->vm_prev;
+       /* we have start < vma->vm_end  */
+
+       /* if it doesn't overlap, we have nothing.. */
+       if (vma->vm_start >= end)
+               return 0;
 
        /*
         * If we need to split any vma, do it now to save pain later.
@@ -2882,6 +2612,8 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
        /* Fix up all other VM information */
        remove_vma_list(mm, vma);
 
+
+       validate_mm(mm);
        return downgrade ? 1 : 0;
 
 map_count_exceeded:
@@ -3020,11 +2752,11 @@ out:
  *  anonymous maps.  eventually we may be able to do some
  *  brk-specific accounting here.
  */
-static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long flags, struct list_head *uf)
+static int do_brk_flags(unsigned long addr, unsigned long len,
+                       unsigned long flags, struct list_head *uf)
 {
        struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma, *prev;
-       struct rb_node **rb_link, *rb_parent;
        pgoff_t pgoff = addr >> PAGE_SHIFT;
        int error;
        unsigned long mapped_addr;
@@ -3043,8 +2775,8 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
        if (error)
                return error;
 
-       /* Clear old maps, set up prev, rb_link, rb_parent, and uf */
-       if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+       /* Clear old maps, set up prev and uf */
+       if (munmap_vma_range(mm, addr, len, &prev, uf))
                return -ENOMEM;
 
        /* Check against address space limits *after* clearing old maps... */
@@ -3078,7 +2810,7 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
        vma->vm_pgoff = pgoff;
        vma->vm_flags = flags;
        vma->vm_page_prot = vm_get_page_prot(flags);
-       if (vma_link(mm, vma, prev, rb_link, rb_parent))
+       if (vma_link(mm, vma, prev))
                goto no_vma_link;
 
 out:
@@ -3197,29 +2929,12 @@ void exit_mmap(struct mm_struct *mm)
 int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
 {
        struct vm_area_struct *prev;
-       struct rb_node **rb_link, *rb_parent;
-       unsigned long start = vma->vm_start;
-       struct vm_area_struct *overlap = NULL;
        unsigned long charged = vma_pages(vma);
 
-       if (find_vma_links(mm, vma->vm_start, vma->vm_end,
-                          &prev, &rb_link, &rb_parent))
 
-       if (find_vma_intersection(mm, vma->vm_start, vma->vm_end))
+       if (range_has_overlap(mm, vma->vm_start, vma->vm_end, &prev))
                return -ENOMEM;
 
-       overlap = mt_find(&mm->mm_mt, &start, vma->vm_end - 1);
-       if (overlap) {
-
-               pr_err("Found vma ending at %lu\n", start - 1);
-               pr_err("vma : %lu => %lu-%lu\n", (unsigned long)overlap,
-                               overlap->vm_start, overlap->vm_end - 1);
-#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
-               mt_dump(&mm->mm_mt);
-#endif
-               BUG();
-       }
-
        if ((vma->vm_flags & VM_ACCOUNT) &&
             security_vm_enough_memory_mm(mm, charged))
                return -ENOMEM;
@@ -3241,7 +2956,7 @@ int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
                vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
        }
 
-       if (vma_link(mm, vma, prev, rb_link, rb_parent)) {
+       if (vma_link(mm, vma, prev)) {
                vm_unacct_memory(charged);
                return -ENOMEM;
        }
@@ -3261,9 +2976,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
        unsigned long vma_start = vma->vm_start;
        struct mm_struct *mm = vma->vm_mm;
        struct vm_area_struct *new_vma, *prev;
-       struct rb_node **rb_link, *rb_parent;
        bool faulted_in_anon_vma = true;
-       unsigned long index = addr;
 
        validate_mm_mt(mm);
        /*
@@ -3275,10 +2988,9 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
                faulted_in_anon_vma = false;
        }
 
-       if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent))
+       if (range_has_overlap(mm, addr, addr + len, &prev))
                return NULL;    /* should never get here */
-       if (mt_find(&mm->mm_mt, &index, addr+len - 1))
-               BUG();
+
        new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
                            vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
                            vma->vm_userfaultfd_ctx, anon_vma_name(vma));
@@ -3319,12 +3031,16 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
                        get_file(new_vma->vm_file);
                if (new_vma->vm_ops && new_vma->vm_ops->open)
                        new_vma->vm_ops->open(new_vma);
-               vma_link(mm, new_vma, prev, rb_link, rb_parent);
+               if (vma_link(mm, new_vma, prev))
+                       goto out_vma_link;
                *need_rmap_locks = false;
        }
        validate_mm_mt(mm);
        return new_vma;
 
+out_vma_link:
+       if (new_vma->vm_ops && new_vma->vm_ops->close)
+               new_vma->vm_ops->close(new_vma);
 out_free_mempol:
        mpol_put(vma_policy(new_vma));
 out_free_vma:
index c63793c..321c7e6 100644 (file)
@@ -566,9 +566,9 @@ void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
  */
 static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
 {
-       struct vm_area_struct *pvma, *prev;
        struct address_space *mapping;
-       struct rb_node **p, *parent, *rb_prev;
+       struct vm_area_struct *prev;
+       MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_end);
 
        BUG_ON(!vma->vm_region);
 
@@ -586,42 +586,10 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
                i_mmap_unlock_write(mapping);
        }
 
+       prev = mas_prev(&mas, 0);
+       mas_reset(&mas);
        /* add the VMA to the tree */
-       parent = rb_prev = NULL;
-       p = &mm->mm_rb.rb_node;
-       while (*p) {
-               parent = *p;
-               pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
-
-               /* sort by: start addr, end addr, VMA struct addr in that order
-                * (the latter is necessary as we may get identical VMAs) */
-               if (vma->vm_start < pvma->vm_start)
-                       p = &(*p)->rb_left;
-               else if (vma->vm_start > pvma->vm_start) {
-                       rb_prev = parent;
-                       p = &(*p)->rb_right;
-               } else if (vma->vm_end < pvma->vm_end)
-                       p = &(*p)->rb_left;
-               else if (vma->vm_end > pvma->vm_end) {
-                       rb_prev = parent;
-                       p = &(*p)->rb_right;
-               } else if (vma < pvma)
-                       p = &(*p)->rb_left;
-               else if (vma > pvma) {
-                       rb_prev = parent;
-                       p = &(*p)->rb_right;
-               } else
-                       BUG();
-       }
-
-       rb_link_node(&vma->vm_rb, parent, p);
-       rb_insert_color(&vma->vm_rb, &mm->mm_rb);
-
-       /* add VMA to the VMA list also */
-       prev = NULL;
-       if (rb_prev)
-               prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
-
+       vma_mas_store(vma, &mas);
        __vma_link_list(mm, vma, prev);
 }
 
@@ -634,6 +602,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
        struct address_space *mapping;
        struct mm_struct *mm = vma->vm_mm;
        struct task_struct *curr = current;
+       MA_STATE(mas, &vma->vm_mm->mm_mt, 0, 0);
 
        mm->map_count--;
        for (i = 0; i < VMACACHE_SIZE; i++) {
@@ -656,8 +625,7 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
        }
 
        /* remove from the MM's tree and list */
-       rb_erase(&vma->vm_rb, &mm->mm_rb);
-
+       vma_mas_remove(vma, &mas);
        __vma_unlink_list(mm, vma);
 }
 
@@ -681,24 +649,19 @@ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
 {
        struct vm_area_struct *vma;
+       MA_STATE(mas, &mm->mm_mt, addr, addr);
 
        /* check the cache first */
        vma = vmacache_find(mm, addr);
        if (likely(vma))
                return vma;
 
-       /* trawl the list (there may be multiple mappings in which addr
-        * resides) */
-       for (vma = mm->mmap; vma; vma = vma->vm_next) {
-               if (vma->vm_start > addr)
-                       return NULL;
-               if (vma->vm_end > addr) {
-                       vmacache_update(addr, vma);
-                       return vma;
-               }
-       }
+       vma = mas_walk(&mas);
 
-       return NULL;
+       if (vma)
+               vmacache_update(addr, vma);
+
+       return vma;
 }
 EXPORT_SYMBOL(find_vma);
 
@@ -730,26 +693,23 @@ static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
 {
        struct vm_area_struct *vma;
        unsigned long end = addr + len;
+       MA_STATE(mas, &mm->mm_mt, addr, addr);
 
        /* check the cache first */
        vma = vmacache_find_exact(mm, addr, end);
        if (vma)
                return vma;
 
-       /* trawl the list (there may be multiple mappings in which addr
-        * resides) */
-       for (vma = mm->mmap; vma; vma = vma->vm_next) {
-               if (vma->vm_start < addr)
-                       continue;
-               if (vma->vm_start > addr)
-                       return NULL;
-               if (vma->vm_end == end) {
-                       vmacache_update(addr, vma);
-                       return vma;
-               }
-       }
+       vma = mas_walk(&mas);
+       if (!vma)
+               return NULL;
+       if (vma->vm_start != addr)
+               return NULL;
+       if (vma->vm_end != end)
+               return NULL;
 
-       return NULL;
+       vmacache_update(addr, vma);
+       return vma;
 }
 
 /*
@@ -1546,6 +1506,7 @@ void exit_mmap(struct mm_struct *mm)
                delete_vma(mm, vma);
                cond_resched();
        }
+       __mt_destroy(&mm->mm_mt);
 }
 
 int vm_brk(unsigned long addr, unsigned long len)
index 8d944ce..10effe2 100644 (file)
--- a/mm/util.c
+++ b/mm/util.c
@@ -288,6 +288,8 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
        vma->vm_next = next;
        if (next)
                next->vm_prev = vma;
+       else
+               mm->highest_vm_end = vm_end_gap(vma);
 }
 
 void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma)
@@ -300,8 +302,14 @@ void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma)
                prev->vm_next = next;
        else
                mm->mmap = next;
-       if (next)
+       if (next) {
                next->vm_prev = prev;
+       } else {
+               if (prev)
+                       mm->highest_vm_end = vm_end_gap(prev);
+               else
+                       mm->highest_vm_end = 0;
+       }
 }
 
 /* Check if the vma is being used as a stack by this task */