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authorJason Gunthorpe <jgg@mellanox.com>2019-08-06 20:15:38 -0300
committerJason Gunthorpe <jgg@mellanox.com>2019-08-16 11:44:48 -0300
commit56c57103db17db9ecdad0507a3f0e3eea747fabe (patch)
tree7615cdd6e0936d1739b42983f3ec19b81fac1ca0 /mm/mmu_notifier.c
parent9c240a7bb33787d4fed56508425ae0b2936b1674 (diff)
downloadlinux-56c57103db17db9ecdad0507a3f0e3eea747fabe.tar.bz2
mm/mmu_notifiers: hoist do_mmu_notifier_register down_write to the caller
This simplifies the code to not have so many one line functions and extra logic. __mmu_notifier_register() simply becomes the entry point to register the notifier, and the other one calls it under lock. Also add a lockdep_assert to check that the callers are holding the lock as expected. Link: https://lore.kernel.org/r/20190806231548.25242-2-jgg@ziepe.ca Suggested-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Tested-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'mm/mmu_notifier.c')
-rw-r--r--mm/mmu_notifier.c35
1 files changed, 14 insertions, 21 deletions
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index b5670620aea0..218a6f108bc2 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -236,22 +236,22 @@ void __mmu_notifier_invalidate_range(struct mm_struct *mm,
}
EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range);
-static int do_mmu_notifier_register(struct mmu_notifier *mn,
- struct mm_struct *mm,
- int take_mmap_sem)
+/*
+ * Same as mmu_notifier_register but here the caller must hold the
+ * mmap_sem in write mode.
+ */
+int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
{
struct mmu_notifier_mm *mmu_notifier_mm;
int ret;
+ lockdep_assert_held_write(&mm->mmap_sem);
BUG_ON(atomic_read(&mm->mm_users) <= 0);
- ret = -ENOMEM;
mmu_notifier_mm = kmalloc(sizeof(struct mmu_notifier_mm), GFP_KERNEL);
if (unlikely(!mmu_notifier_mm))
- goto out;
+ return -ENOMEM;
- if (take_mmap_sem)
- down_write(&mm->mmap_sem);
ret = mm_take_all_locks(mm);
if (unlikely(ret))
goto out_clean;
@@ -279,13 +279,11 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn,
mm_drop_all_locks(mm);
out_clean:
- if (take_mmap_sem)
- up_write(&mm->mmap_sem);
kfree(mmu_notifier_mm);
-out:
BUG_ON(atomic_read(&mm->mm_users) <= 0);
return ret;
}
+EXPORT_SYMBOL_GPL(__mmu_notifier_register);
/*
* Must not hold mmap_sem nor any other VM related lock when calling
@@ -302,19 +300,14 @@ out:
*/
int mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
{
- return do_mmu_notifier_register(mn, mm, 1);
-}
-EXPORT_SYMBOL_GPL(mmu_notifier_register);
+ int ret;
-/*
- * Same as mmu_notifier_register but here the caller must hold the
- * mmap_sem in write mode.
- */
-int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
-{
- return do_mmu_notifier_register(mn, mm, 0);
+ down_write(&mm->mmap_sem);
+ ret = __mmu_notifier_register(mn, mm);
+ up_write(&mm->mmap_sem);
+ return ret;
}
-EXPORT_SYMBOL_GPL(__mmu_notifier_register);
+EXPORT_SYMBOL_GPL(mmu_notifier_register);
/* this is called after the last mmu_notifier_unregister() returned */
void __mmu_notifier_mm_destroy(struct mm_struct *mm)