3a39201543
It is not real zero-copy since the data is still copied in the kernel, but it avoids copying the data inside libiscsi as well as in the callback. For SCSI tasks that will return data from the target, the application can now specify application buffers for libiscsi to read the data directly into. This is done by calling scsi_task_add_data_in_buffer(task, ... These buffers need not be linear, you can specify different areas to read into by calling this function several times. See examples/iscsiclient.c for an example.
135 lines
3.2 KiB
C
135 lines
3.2 KiB
C
/*
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Copyright (C) 2010 by Ronnie Sahlberg <ronniesahlberg@gmail.com>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include "iscsi.h"
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#include "iscsi-private.h"
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int
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iscsi_nop_out_async(struct iscsi_context *iscsi, iscsi_command_cb cb,
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unsigned char *data, int len, void *private_data)
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{
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struct iscsi_pdu *pdu;
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if (iscsi->is_loggedin == 0) {
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iscsi_set_error(iscsi, "trying to send nop-out while not "
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"logged in");
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return -1;
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}
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pdu = iscsi_allocate_pdu(iscsi, ISCSI_PDU_NOP_OUT, ISCSI_PDU_NOP_IN);
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if (pdu == NULL) {
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iscsi_set_error(iscsi, "Failed to allocate nop-out pdu");
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return -1;
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}
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/* immediate flag */
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iscsi_pdu_set_immediate(pdu);
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/* flags */
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iscsi_pdu_set_pduflags(pdu, 0x80);
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/* ttt */
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iscsi_pdu_set_ttt(pdu, 0xffffffff);
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/* lun */
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iscsi_pdu_set_lun(pdu, 0);
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/* cmdsn is not increased if Immediate delivery*/
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iscsi_pdu_set_cmdsn(pdu, iscsi->cmdsn);
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pdu->cmdsn = iscsi->cmdsn;
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/* exp statsn */
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iscsi_pdu_set_expstatsn(pdu, iscsi->statsn+1);
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pdu->callback = cb;
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pdu->private_data = private_data;
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if (iscsi_pdu_add_data(iscsi, pdu, data, len) != 0) {
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iscsi_set_error(iscsi, "Failed to add outdata to nop-out");
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iscsi_free_pdu(iscsi, pdu);
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return -1;
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}
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if (iscsi_queue_pdu(iscsi, pdu) != 0) {
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iscsi_set_error(iscsi, "failed to queue iscsi nop-out pdu");
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iscsi_free_pdu(iscsi, pdu);
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return -1;
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}
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return 0;
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}
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int
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iscsi_send_target_nop_out(struct iscsi_context *iscsi, uint32_t ttt)
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{
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struct iscsi_pdu *pdu;
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pdu = iscsi_allocate_pdu_with_itt_flags(iscsi, ISCSI_PDU_NOP_OUT, ISCSI_PDU_NO_PDU,
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0xffffffff,ISCSI_PDU_DELETE_WHEN_SENT|ISCSI_PDU_NO_CALLBACK);
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if (pdu == NULL) {
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iscsi_set_error(iscsi, "Failed to allocate nop-out pdu");
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return -1;
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}
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/* immediate flag */
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iscsi_pdu_set_immediate(pdu);
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/* flags */
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iscsi_pdu_set_pduflags(pdu, 0x80);
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/* ttt */
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iscsi_pdu_set_ttt(pdu, ttt);
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/* lun */
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iscsi_pdu_set_lun(pdu, 0);
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/* cmdsn is not increased if Immediate delivery*/
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iscsi_pdu_set_cmdsn(pdu, iscsi->cmdsn);
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pdu->cmdsn = iscsi->cmdsn;
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/* exp statsn */
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iscsi_pdu_set_expstatsn(pdu, iscsi->statsn+1);
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if (iscsi_queue_pdu(iscsi, pdu) != 0) {
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iscsi_set_error(iscsi, "failed to queue iscsi nop-out pdu");
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iscsi_free_pdu(iscsi, pdu);
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return -1;
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}
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return 0;
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}
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int
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iscsi_process_nop_out_reply(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
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struct iscsi_in_pdu *in)
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{
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struct iscsi_data data;
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data.data = NULL;
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data.size = 0;
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if (in->data_pos > ISCSI_HEADER_SIZE) {
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data.data = in->data;
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data.size = in->data_pos;
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}
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pdu->callback(iscsi, SCSI_STATUS_GOOD, &data, pdu->private_data);
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return 0;
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}
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