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Commit 7cb001d4 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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scsi_tcp: block BH in TCP callbacks 



iscsi_sw_tcp_data_ready() and iscsi_sw_tcp_state_change() were
using read_lock(&sk->sk_callback_lock) which is fine if caller
disabled BH.

TCP stack no longer has this requirement and can run from
process context.

Use read_lock_bh() variant to restore previous assumption.

Ideally this code could use RCU instead...

Fixes: 5413d1ba ("net: do not block BH while processing socket backlog")
Fixes: d41a69f1 ("tcp: make tcp_sendmsg() aware of socket backlog")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Venkatesh Srinivas <venkateshs@google.com>
Acked-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e00be9e4

drivers/scsi/iscsi_tcp.c

+6 −6
Original line number Diff line number Diff line
@@ -131,10 +131,10 @@ static void iscsi_sw_tcp_data_ready(struct sock *sk) 
	struct iscsi_tcp_conn *tcp_conn;

	read_descriptor_t rd_desc;



	read_lock(&sk->sk_callback_lock);

	read_lock_bh(&sk->sk_callback_lock);

	conn = sk->sk_user_data;

	if (!conn) {

		read_unlock(&sk->sk_callback_lock);

		read_unlock_bh(&sk->sk_callback_lock);

		return;

	}

	tcp_conn = conn->dd_data;
@@ -154,7 +154,7 @@ static void iscsi_sw_tcp_data_ready(struct sock *sk) 
	/* If we had to (atomically) map a highmem page,

	 * unmap it now. */

	iscsi_tcp_segment_unmap(&tcp_conn->in.segment);

	read_unlock(&sk->sk_callback_lock);

	read_unlock_bh(&sk->sk_callback_lock);

}



static void iscsi_sw_tcp_state_change(struct sock *sk)
@@ -165,10 +165,10 @@ static void iscsi_sw_tcp_state_change(struct sock *sk) 
	struct iscsi_session *session;

	void (*old_state_change)(struct sock *);



	read_lock(&sk->sk_callback_lock);

	read_lock_bh(&sk->sk_callback_lock);

	conn = sk->sk_user_data;

	if (!conn) {

		read_unlock(&sk->sk_callback_lock);

		read_unlock_bh(&sk->sk_callback_lock);

		return;

	}

	session = conn->session;
@@ -179,7 +179,7 @@ static void iscsi_sw_tcp_state_change(struct sock *sk) 
	tcp_sw_conn = tcp_conn->dd_data;

	old_state_change = tcp_sw_conn->old_state_change;



	read_unlock(&sk->sk_callback_lock);

	read_unlock_bh(&sk->sk_callback_lock);



	old_state_change(sk);

}