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Commit 2c4f6219 authored by David S. Miller's avatar David S. Miller
Browse files

[TCP]: Fix MD5 signature pool locking. 



The locking calls assumed that these code paths were only
invoked in software interrupt context, but that isn't true.

Therefore we need to use spin_{lock,unlock}_bh() throughout.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7f62ad5d

net/ipv4/tcp.c

+12 −12
Original line number Diff line number Diff line
@@ -2266,12 +2266,12 @@ void tcp_free_md5sig_pool(void) 
{

	struct tcp_md5sig_pool **pool = NULL;



	spin_lock(&tcp_md5sig_pool_lock);

	spin_lock_bh(&tcp_md5sig_pool_lock);

	if (--tcp_md5sig_users == 0) {

		pool = tcp_md5sig_pool;

		tcp_md5sig_pool = NULL;

	}

	spin_unlock(&tcp_md5sig_pool_lock);

	spin_unlock_bh(&tcp_md5sig_pool_lock);

	if (pool)

		__tcp_free_md5sig_pool(pool);

}
@@ -2314,36 +2314,36 @@ struct tcp_md5sig_pool **tcp_alloc_md5sig_pool(void) 
	int alloc = 0;



retry:

	spin_lock(&tcp_md5sig_pool_lock);

	spin_lock_bh(&tcp_md5sig_pool_lock);

	pool = tcp_md5sig_pool;

	if (tcp_md5sig_users++ == 0) {

		alloc = 1;

		spin_unlock(&tcp_md5sig_pool_lock);

		spin_unlock_bh(&tcp_md5sig_pool_lock);

	} else if (!pool) {

		tcp_md5sig_users--;

		spin_unlock(&tcp_md5sig_pool_lock);

		spin_unlock_bh(&tcp_md5sig_pool_lock);

		cpu_relax();

		goto retry;

	} else

		spin_unlock(&tcp_md5sig_pool_lock);

		spin_unlock_bh(&tcp_md5sig_pool_lock);



	if (alloc) {

		/* we cannot hold spinlock here because this may sleep. */

		struct tcp_md5sig_pool **p = __tcp_alloc_md5sig_pool();

		spin_lock(&tcp_md5sig_pool_lock);

		spin_lock_bh(&tcp_md5sig_pool_lock);

		if (!p) {

			tcp_md5sig_users--;

			spin_unlock(&tcp_md5sig_pool_lock);

			spin_unlock_bh(&tcp_md5sig_pool_lock);

			return NULL;

		}

		pool = tcp_md5sig_pool;

		if (pool) {

			/* oops, it has already been assigned. */

			spin_unlock(&tcp_md5sig_pool_lock);

			spin_unlock_bh(&tcp_md5sig_pool_lock);

			__tcp_free_md5sig_pool(p);

		} else {

			tcp_md5sig_pool = pool = p;

			spin_unlock(&tcp_md5sig_pool_lock);

			spin_unlock_bh(&tcp_md5sig_pool_lock);

		}

	}

	return pool;
@@ -2354,11 +2354,11 @@ EXPORT_SYMBOL(tcp_alloc_md5sig_pool); 
struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu)

{

	struct tcp_md5sig_pool **p;

	spin_lock(&tcp_md5sig_pool_lock);

	spin_lock_bh(&tcp_md5sig_pool_lock);

	p = tcp_md5sig_pool;

	if (p)

		tcp_md5sig_users++;

	spin_unlock(&tcp_md5sig_pool_lock);

	spin_unlock_bh(&tcp_md5sig_pool_lock);

	return (p ? *per_cpu_ptr(p, cpu) : NULL);

}