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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: 5413d1babe ("net: do not block BH while processing socket backlog")
Fixes: d41a69f1d3 ("tcp: make tcp_sendmsg() aware of socket backlog")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Venkatesh Srinivas <venkateshs@google.com>
Acked-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2016-05-17 17:44:06 -07:00 committed by David S. Miller
parent e00be9e4d0
commit 7cb001d4c4
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/scsi/iscsi_tcp.c
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@ -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);
}