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Commit cb54a0f2 authored by Linux Build Service Account's avatar Linux Build Service Account Committed by Gerrit - the friendly Code Review server
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Merge "mm: zcache: fix locking sequence"

parents 5e0b4625 6bbf85fe

mm/zcache.c

+18 −5
Original line number Diff line number Diff line
@@ -569,10 +569,17 @@ static int zcache_store_zaddr(struct zcache_pool *zpool, 
	/* Insert zcache_ra_handle to ratree */

	ret = radix_tree_insert(&rbnode->ratree, ra_index,

				(void *)zaddr);

	if (unlikely(ret))

		if (zcache_rbnode_empty(rbnode))

			zcache_rbnode_isolate(zpool, rbnode, 0);

	spin_unlock_irqrestore(&rbnode->ra_lock, flags);

	if (unlikely(ret)) {

		write_lock_irqsave(&zpool->rb_lock, flags);

		spin_lock(&rbnode->ra_lock);



		if (zcache_rbnode_empty(rbnode))

			zcache_rbnode_isolate(zpool, rbnode, 1);



		spin_unlock(&rbnode->ra_lock);

		write_unlock_irqrestore(&zpool->rb_lock, flags);

	}



	kref_put(&rbnode->refcount, zcache_rbnode_release);

	return ret;
@@ -598,10 +605,16 @@ static void *zcache_load_delete_zaddr(struct zcache_pool *zpool, 


	spin_lock_irqsave(&rbnode->ra_lock, flags);

	zaddr = radix_tree_delete(&rbnode->ratree, ra_index);

	if (zcache_rbnode_empty(rbnode))

		zcache_rbnode_isolate(zpool, rbnode, 0);

	spin_unlock_irqrestore(&rbnode->ra_lock, flags);



	/* rb_lock and ra_lock must be taken again in the given sequence */

	write_lock_irqsave(&zpool->rb_lock, flags);

	spin_lock(&rbnode->ra_lock);

	if (zcache_rbnode_empty(rbnode))

		zcache_rbnode_isolate(zpool, rbnode, 1);

	spin_unlock(&rbnode->ra_lock);

	write_unlock_irqrestore(&zpool->rb_lock, flags);



	kref_put(&rbnode->refcount, zcache_rbnode_release);

out:

	return zaddr;