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Subject[RFC][PATCH 8/7] lockdep: annotate mm_take_all_locks()
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Date
Subject: lockdep: annotate mm_take_all_locks()

The nesting is correct due to holding mmap_sem, use the new annotation
to annotate this.

This doesn't solve the MAX_LOCK_DEPTH issue, but 48 seems enough for
the current kvm usage, which does this early on in the life of an mm.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
mm/mmap.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
Index: linux-2.6/mm/mmap.c
===================================================================
--- linux-2.6.orig/mm/mmap.c
+++ linux-2.6/mm/mmap.c
@@ -2273,14 +2273,14 @@ int install_special_mapping(struct mm_st

static DEFINE_MUTEX(mm_all_locks_mutex);

-static void vm_lock_anon_vma(struct anon_vma *anon_vma)
+static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
{
if (!test_bit(0, (unsigned long *) &anon_vma->head.next)) {
/*
* The LSB of head.next can't change from under us
* because we hold the mm_all_locks_mutex.
*/
- spin_lock(&anon_vma->lock);
+ spin_lock_nest_lock(&anon_vma->lock, &mm->mmap_sem);
/*
* We can safely modify head.next after taking the
* anon_vma->lock. If some other vma in this mm shares
@@ -2296,7 +2296,7 @@ static void vm_lock_anon_vma(struct anon
}
}

-static void vm_lock_mapping(struct address_space *mapping)
+static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
{
if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) {
/*
@@ -2310,7 +2310,7 @@ static void vm_lock_mapping(struct addre
*/
if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
BUG();
- spin_lock(&mapping->i_mmap_lock);
+ spin_lock_nest_lock(&mapping->i_mmap_lock, &mm->mmap_sem);
}
}

@@ -2359,9 +2359,9 @@ int mm_take_all_locks(struct mm_struct *
if (signal_pending(current))
goto out_unlock;
if (vma->anon_vma)
- vm_lock_anon_vma(vma->anon_vma);
+ vm_lock_anon_vma(mm, vma->anon_vma);
if (vma->vm_file && vma->vm_file->f_mapping)
- vm_lock_mapping(vma->vm_file->f_mapping);
+ vm_lock_mapping(mm, vma->vm_file->f_mapping);
}
ret = 0;




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