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dax: Avoid losing wakeup in dax_lock_mapping_entry

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commit 25bbe21bf427a81b8e3ccd480ea0e1d940256156 upstream.

After calling get_unlocked_entry(), you have to call
put_unlocked_entry() to avoid subsequent waiters losing wakeups.

Fixes: c2a7d2a11552 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Matthew Wilcox 2018-11-16 15:50:02 -05:00 committed by Greg Kroah-Hartman
parent 9dec38554a
commit e7a121e34c
1 changed files with 6 additions and 1 deletions
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7
fs/dax.c
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@ -217,6 +217,9 @@ static inline void *unlock_slot(struct address_space *mapping, void **slot)
return (void *)entry;
}
static void put_unlocked_mapping_entry(struct address_space *mapping,
pgoff_t index, void *entry);
/*
* Lookup entry in radix tree, wait for it to become unlocked if it is
* exceptional entry and return it. The caller must call
@ -256,8 +259,10 @@ static void *__get_unlocked_mapping_entry(struct address_space *mapping,
revalidate = wait_fn();
finish_wait(wq, &ewait.wait);
xa_lock_irq(&mapping->i_pages);
if (revalidate)
if (revalidate) {
put_unlocked_mapping_entry(mapping, index, entry);
return ERR_PTR(-EAGAIN);
}
}
}