[SCSI] iscsi_tcp: prepare helpers for LLDs that can offload some operations
cxgb3i is unlike qla4xxx and bnx2i in that it does not offload entire scsi commands or iscsi sequences. Instead it only offloads the transfer of a ISCSI DATA_IN pdu's data, the digests and padding. This patch fixes up the iscsi tcp recv path so that it exports its skb recv processing so cxgb3i and other drivers can call them. All they have to do is pass the function the skb with the hdr or data pdu header and this function will do the rest. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
Mike Christie
James Bottomley
parent
b29f841378
commit
63c62f1cb9
2 changed files with 115 additions and 56 deletions
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@ -486,7 +486,8 @@ iscsi_tcp_data_recv_prep(struct iscsi_tcp_conn *tcp_conn)
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struct iscsi_conn *conn = tcp_conn->iscsi_conn;
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struct hash_desc *rx_hash = NULL;
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if (conn->datadgst_en)
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if (conn->datadgst_en &
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!(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
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rx_hash = &tcp_conn->rx_hash;
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iscsi_segment_init_linear(&tcp_conn->in.segment,
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@ -774,7 +775,8 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
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* we move on to the next scatterlist entry and
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* update the digest per-entry.
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*/
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if (conn->datadgst_en)
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if (conn->datadgst_en &&
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!(conn->session->tt->caps & CAP_DIGEST_OFFLOAD))
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rx_hash = &tcp_conn->rx_hash;
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debug_tcp("iscsi_tcp_begin_data_in(%p, offset=%d, "
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@ -902,22 +904,115 @@ iscsi_tcp_hdr_recv_done(struct iscsi_tcp_conn *tcp_conn,
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* and go back for more. */
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if (conn->hdrdgst_en) {
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if (segment->digest_len == 0) {
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/*
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* Even if we offload the digest processing we
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* splice it in so we can increment the skb/segment
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* counters in preparation for the data segment.
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*/
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iscsi_tcp_segment_splice_digest(segment,
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segment->recv_digest);
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return 0;
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}
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iscsi_tcp_dgst_header(&tcp_conn->rx_hash, hdr,
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segment->total_copied - ISCSI_DIGEST_SIZE,
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segment->digest);
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if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
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return ISCSI_ERR_HDR_DGST;
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if (!(conn->session->tt->caps & CAP_DIGEST_OFFLOAD)) {
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iscsi_tcp_dgst_header(&tcp_conn->rx_hash, hdr,
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segment->total_copied - ISCSI_DIGEST_SIZE,
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segment->digest);
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if (!iscsi_tcp_dgst_verify(tcp_conn, segment))
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return ISCSI_ERR_HDR_DGST;
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}
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}
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tcp_conn->in.hdr = hdr;
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return iscsi_tcp_hdr_dissect(conn, hdr);
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}
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inline int iscsi_tcp_recv_segment_is_hdr(struct iscsi_tcp_conn *tcp_conn)
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{
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return tcp_conn->in.segment.done == iscsi_tcp_hdr_recv_done;
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}
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enum {
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ISCSI_TCP_SEGMENT_DONE, /* curr seg has been processed */
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ISCSI_TCP_SKB_DONE, /* skb is out of data */
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ISCSI_TCP_CONN_ERR, /* iscsi layer has fired a conn err */
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ISCSI_TCP_SUSPENDED, /* conn is suspended */
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};
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/**
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* iscsi_tcp_recv_skb - Process skb
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* @conn: iscsi connection
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* @skb: network buffer with header and/or data segment
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* @offset: offset in skb
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* @offload: bool indicating if transfer was offloaded
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*/
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int iscsi_tcp_recv_skb(struct iscsi_conn *conn, struct sk_buff *skb,
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unsigned int offset, bool offloaded, int *status)
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{
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struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
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struct iscsi_segment *segment = &tcp_conn->in.segment;
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struct skb_seq_state seq;
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unsigned int consumed = 0;
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int rc = 0;
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debug_tcp("in %d bytes\n", skb->len - offset);
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if (unlikely(conn->suspend_rx)) {
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debug_tcp("conn %d Rx suspended!\n", conn->id);
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*status = ISCSI_TCP_SUSPENDED;
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return 0;
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}
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if (offloaded) {
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segment->total_copied = segment->total_size;
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goto segment_done;
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}
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skb_prepare_seq_read(skb, offset, skb->len, &seq);
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while (1) {
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unsigned int avail;
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const u8 *ptr;
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avail = skb_seq_read(consumed, &ptr, &seq);
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if (avail == 0) {
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debug_tcp("no more data avail. Consumed %d\n",
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consumed);
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*status = ISCSI_TCP_SKB_DONE;
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skb_abort_seq_read(&seq);
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goto skb_done;
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}
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BUG_ON(segment->copied >= segment->size);
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debug_tcp("skb %p ptr=%p avail=%u\n", skb, ptr, avail);
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rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
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BUG_ON(rc == 0);
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consumed += rc;
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if (segment->total_copied >= segment->total_size) {
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skb_abort_seq_read(&seq);
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goto segment_done;
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}
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}
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segment_done:
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*status = ISCSI_TCP_SEGMENT_DONE;
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debug_tcp("segment done\n");
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rc = segment->done(tcp_conn, segment);
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if (rc != 0) {
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*status = ISCSI_TCP_CONN_ERR;
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debug_tcp("Error receiving PDU, errno=%d\n", rc);
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iscsi_conn_failure(conn, rc);
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return 0;
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}
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/* The done() functions sets up the next segment. */
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skb_done:
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conn->rxdata_octets += consumed;
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return consumed;
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}
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EXPORT_SYMBOL_GPL(iscsi_tcp_recv_skb);
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/**
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* iscsi_tcp_recv - TCP receive in sendfile fashion
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* @rd_desc: read descriptor
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@ -930,57 +1025,20 @@ iscsi_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
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unsigned int offset, size_t len)
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{
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struct iscsi_conn *conn = rd_desc->arg.data;
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struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
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struct iscsi_segment *segment = &tcp_conn->in.segment;
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struct skb_seq_state seq;
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unsigned int consumed = 0;
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int rc = 0;
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unsigned int consumed, total_consumed = 0;
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int status;
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debug_tcp("in %d bytes\n", skb->len - offset);
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if (unlikely(conn->suspend_rx)) {
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debug_tcp("conn %d Rx suspended!\n", conn->id);
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return 0;
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}
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do {
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status = 0;
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consumed = iscsi_tcp_recv_skb(conn, skb, offset, 0, &status);
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offset += consumed;
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total_consumed += consumed;
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} while (consumed != 0 && status != ISCSI_TCP_SKB_DONE);
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skb_prepare_seq_read(skb, offset, skb->len, &seq);
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while (1) {
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unsigned int avail;
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const u8 *ptr;
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avail = skb_seq_read(consumed, &ptr, &seq);
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if (avail == 0) {
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debug_tcp("no more data avail. Consumed %d\n",
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consumed);
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break;
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}
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BUG_ON(segment->copied >= segment->size);
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debug_tcp("skb %p ptr=%p avail=%u\n", skb, ptr, avail);
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rc = iscsi_tcp_segment_recv(tcp_conn, segment, ptr, avail);
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BUG_ON(rc == 0);
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consumed += rc;
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if (segment->total_copied >= segment->total_size) {
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debug_tcp("segment done\n");
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rc = segment->done(tcp_conn, segment);
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if (rc != 0) {
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skb_abort_seq_read(&seq);
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goto error;
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}
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/* The done() functions sets up the
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* next segment. */
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}
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}
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skb_abort_seq_read(&seq);
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conn->rxdata_octets += consumed;
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return consumed;
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error:
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debug_tcp("Error receiving PDU, errno=%d\n", rc);
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iscsi_conn_failure(conn, rc);
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return 0;
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debug_tcp("read %d bytes status %d\n", skb->len - offset, status);
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return total_consumed;
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}
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static void
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@ -333,8 +333,9 @@ enum iscsi_host_param {
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#define CAP_TEXT_NEGO 0x80
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#define CAP_MARKERS 0x100
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#define CAP_FW_DB 0x200
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#define CAP_SENDTARGETS_OFFLOAD 0x400
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#define CAP_DATA_PATH_OFFLOAD 0x800
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#define CAP_SENDTARGETS_OFFLOAD 0x400 /* offload discovery process */
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#define CAP_DATA_PATH_OFFLOAD 0x800 /* offload entire IO path */
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#define CAP_DIGEST_OFFLOAD 0x1000 /* offload hdr and data digests */
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/*
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* These flags describes reason of stop_conn() call
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