[SCSI] iscsi: data digest page cache usage fix
Users can write to a page while we are sending it and making digest calculations. This ends up causing us to retry the command when a digest error is later reported. By using sock_no_sendpage when data digests are calculated we can avoid a lot of (not all but it helps) the retries becuase sock_no_sendpage is not zero copy. Signed-off-by: Alex Aizman <itn780@yahoo.com> Signed-off-by: Dmitry Yusupov <dmitry_yus@yahoo.com> Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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@ -1318,15 +1318,15 @@ iscsi_conn_restore_callbacks(struct iscsi_conn *conn)
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* to use tcp_sendmsg().
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*/
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static inline int
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iscsi_send(struct socket *sk, struct iscsi_buf *buf, int size, int flags)
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iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags)
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{
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struct socket *sk = conn->sock;
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int res;
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if ((int)buf->sg.offset >= 0) {
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int offset = buf->sg.offset + buf->sent;
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/* tcp_sendpage */
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res = sk->ops->sendpage(sk, buf->sg.page, offset, size, flags);
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res = conn->sendpage(sk, buf->sg.page, offset, size, flags);
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} else {
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struct msghdr msg;
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@ -1354,7 +1354,6 @@ iscsi_send(struct socket *sk, struct iscsi_buf *buf, int size, int flags)
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static inline int
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iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
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{
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struct socket *sk = conn->sock;
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int flags = 0; /* MSG_DONTWAIT; */
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int res, size;
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@ -1363,7 +1362,7 @@ iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
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if (buf->sent + size != buf->sg.length || datalen)
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flags |= MSG_MORE;
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res = iscsi_send(sk, buf, size, flags);
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res = iscsi_send(conn, buf, size, flags);
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debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);
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if (res >= 0) {
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conn->txdata_octets += res;
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@ -1394,7 +1393,6 @@ static inline int
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iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
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int *count, int *sent)
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{
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struct socket *sk = conn->sock;
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int flags = 0; /* MSG_DONTWAIT; */
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int res, size;
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@ -1405,7 +1403,7 @@ iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
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if (buf->sent + size != buf->sg.length || *count != size)
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flags |= MSG_MORE;
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res = iscsi_send(sk, buf, size, flags);
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res = iscsi_send(conn, buf, size, flags);
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debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",
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size, buf->sent, *count, *sent, res);
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if (res >= 0) {
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@ -2713,6 +2711,8 @@ iscsi_conn_bind(iscsi_sessionh_t sessionh, iscsi_connh_t connh,
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*/
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iscsi_conn_set_callbacks(conn);
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conn->sendpage = conn->sock->ops->sendpage;
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/*
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* set receive state machine into initial state
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*/
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@ -3467,6 +3467,8 @@ iscsi_conn_set_param(iscsi_connh_t connh, enum iscsi_param param,
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if (conn->data_rx_tfm)
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crypto_free_tfm(conn->data_rx_tfm);
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}
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conn->sendpage = conn->datadgst_en ?
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sock_no_sendpage : conn->sock->ops->sendpage;
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break;
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case ISCSI_PARAM_INITIAL_R2T_EN:
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session->initial_r2t_en = value;
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@ -191,6 +191,8 @@ struct iscsi_conn {
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uint32_t sendpage_failures_cnt;
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uint32_t discontiguous_hdr_cnt;
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uint32_t eh_abort_cnt;
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ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
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};
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struct iscsi_session {
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