Use the maple tree iterator to duplicate the mm_struct trees.
Signed-off-by: Liam R. Howlett <[email protected]>
---
include/linux/sched/mm.h | 3 +++
kernel/fork.c | 22 +++++++++++++++++-----
2 files changed, 20 insertions(+), 5 deletions(-)
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index d5ece7a9a403f..919e2e44b764e 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -8,6 +8,7 @@
#include <linux/mm_types.h>
#include <linux/gfp.h>
#include <linux/sync_core.h>
+#include <linux/maple_tree.h>
/*
* Routines for handling mm_structs
@@ -67,11 +68,13 @@ static inline void mmdrop(struct mm_struct *mm)
*/
static inline void mmget(struct mm_struct *mm)
{
+ mt_set_in_rcu(&mm->mm_mt);
atomic_inc(&mm->mm_users);
}
static inline bool mmget_not_zero(struct mm_struct *mm)
{
+ mt_set_in_rcu(&mm->mm_mt);
return atomic_inc_not_zero(&mm->mm_users);
}
diff --git a/kernel/fork.c b/kernel/fork.c
index 23e166d037980..62eba2679216b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -472,7 +472,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
struct rb_node **rb_link, *rb_parent;
int retval;
- unsigned long charge;
+ unsigned long charge = 0;
+ MA_STATE(old_mas, &oldmm->mm_mt, 0, 0);
+ MA_STATE(mas, &mm->mm_mt, 0, 0);
LIST_HEAD(uf);
uprobe_start_dup_mmap();
@@ -506,7 +508,12 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
goto out;
prev = NULL;
- for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
+
+ retval = mas_entry_count(&mas, oldmm->map_count);
+ if (retval)
+ goto fail_nomem;
+
+ mas_for_each(&old_mas, mpnt, ULONG_MAX) {
struct file *file;
if (mpnt->vm_flags & VM_DONTCOPY) {
@@ -520,7 +527,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
*/
if (fatal_signal_pending(current)) {
retval = -EINTR;
- goto out;
+ goto loop_out;
}
if (mpnt->vm_flags & VM_ACCOUNT) {
unsigned long len = vma_pages(mpnt);
@@ -589,7 +596,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
rb_parent = &tmp->vm_rb;
/* Link the vma into the MT */
- vma_store(mm, tmp);
+ mas.index = tmp->vm_start;
+ mas.last = tmp->vm_end - 1;
+ mas_store(&mas, tmp);
mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
@@ -599,14 +608,16 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
tmp->vm_ops->open(tmp);
if (retval)
- goto out;
+ goto loop_out;
}
/* a new mm has just been created */
retval = arch_dup_mmap(oldmm, mm);
+loop_out:
out:
mmap_write_unlock(mm);
flush_tlb_mm(oldmm);
mmap_write_unlock(oldmm);
+ mas_destroy(&mas);
dup_userfaultfd_complete(&uf);
fail_uprobe_end:
uprobe_end_dup_mmap();
@@ -1076,6 +1087,7 @@ static inline void __mmput(struct mm_struct *mm)
{
VM_BUG_ON(atomic_read(&mm->mm_users));
+ mt_clear_in_rcu(&mm->mm_mt);
uprobe_clear_state(mm);
exit_aio(mm);
ksm_exit(mm);
--
2.28.0
