3.2.72-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Marek Marczykowski-Górecki
<marma...@invisiblethingslab.com>
commit 30b03d05e07467b8c6ec683ea96b5bffcbcd3931 upstream.
While gntdev_release() is called the MMU notifier is still registered
and can traverse priv->maps list even if no pages are mapped (which is
the case -- gntdev_release() is called after all). But
gntdev_release() will clear that list, so make sure that only one of
those things happens at the same time.
Signed-off-by: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com>
Signed-off-by: David Vrabel <david.vra...@citrix.com>
[bwh: Backported to 3.2:
- Adjust context
- gntdev_priv::lock is a spinlock rather than a mutex. As gntdev_put_map()
may sleep, we need to unlock inside the loop.]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -493,11 +493,15 @@ static int gntdev_release(struct inode *
pr_debug("priv %p\n", priv);
+ spin_lock(&priv->lock);
while (!list_empty(&priv->maps)) {
map = list_entry(priv->maps.next, struct grant_map, next);
list_del(&map->next);
+ spin_unlock(&priv->lock);
gntdev_put_map(map);
+ spin_lock(&priv->lock);
}
+ spin_unlock(&priv->lock);
if (use_ptemod)
mmu_notifier_unregister(&priv->mn, priv->mm);
--
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