Commit 66204f1d authored by Daniel Vetter's avatar Daniel Vetter Committed by Jason Gunthorpe

mm/mmu_notifiers: prime lockdep

We want to teach lockdep that mmu notifiers can be called from direct
reclaim paths, since on many CI systems load might never reach that
level (e.g. when just running fuzzer or small functional tests).

I've put the annotation into mmu_notifier_register since only when we have
mmu notifiers registered is there any point in teaching lockdep about
them. Also, we already have a kmalloc(, GFP_KERNEL), so this is safe.

Link: https://lore.kernel.org/r/20190826201425.17547-3-daniel.vetter@ffwll.chSuggested-by: default avatarJason Gunthorpe <jgg@mellanox.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent 23b68395
......@@ -243,6 +243,13 @@ int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
lockdep_assert_held_write(&mm->mmap_sem);
BUG_ON(atomic_read(&mm->mm_users) <= 0);
if (IS_ENABLED(CONFIG_LOCKDEP)) {
fs_reclaim_acquire(GFP_KERNEL);
lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
lock_map_release(&__mmu_notifier_invalidate_range_start_map);
fs_reclaim_release(GFP_KERNEL);
}
mn->mm = mm;
mn->users = 1;
......
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