[SCSI] libiscsi: modify libiscsi so it supports offloaded data paths
This patch modifies libiscsi, so drivers like bnx2i and iser can execute
a command from queuecommand/send_pdu instead of having to be queued to
be run in a workq.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 4bc63c4..1e605de 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -79,9 +79,11 @@
* xmit thread
*/
if (!list_empty(&session->leadconn->xmitqueue) ||
- !list_empty(&session->leadconn->mgmtqueue))
- scsi_queue_work(session->host,
- &session->leadconn->xmitwork);
+ !list_empty(&session->leadconn->mgmtqueue)) {
+ if (!(session->tt->caps & CAP_DATA_PATH_OFFLOAD))
+ scsi_queue_work(session->host,
+ &session->leadconn->xmitwork);
+ }
}
}
EXPORT_SYMBOL_GPL(iscsi_update_cmdsn);
@@ -298,8 +300,12 @@
WARN_ON(hdrlength >= 256);
hdr->hlength = hdrlength & 0xFF;
- if (conn->session->tt->init_cmd_task(conn->ctask))
- return EIO;
+ if (conn->session->tt->init_cmd_task &&
+ conn->session->tt->init_cmd_task(ctask))
+ return -EIO;
+
+ ctask->state = ISCSI_TASK_RUNNING;
+ list_move_tail(&ctask->running, &conn->run_list);
conn->scsicmd_pdus_cnt++;
debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x "
@@ -334,7 +340,9 @@
conn->ctask = NULL;
list_del_init(&ctask->running);
__kfifo_put(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
- sc->scsi_done(sc);
+
+ if (sc->scsi_done)
+ sc->scsi_done(sc);
}
static void __iscsi_get_ctask(struct iscsi_cmd_task *ctask)
@@ -403,6 +411,50 @@
}
EXPORT_SYMBOL_GPL(iscsi_free_mgmt_task);
+static int iscsi_prep_mtask(struct iscsi_conn *conn,
+ struct iscsi_mgmt_task *mtask)
+{
+ struct iscsi_session *session = conn->session;
+ struct iscsi_hdr *hdr = mtask->hdr;
+ struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;
+
+ if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
+ return -ENOTCONN;
+
+ if (hdr->opcode != (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) &&
+ hdr->opcode != (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
+ nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
+ /*
+ * pre-format CmdSN for outgoing PDU.
+ */
+ nop->cmdsn = cpu_to_be32(session->cmdsn);
+ if (hdr->itt != RESERVED_ITT) {
+ hdr->itt = build_itt(mtask->itt, session->age);
+ /*
+ * TODO: We always use immediate, so we never hit this.
+ * If we start to send tmfs or nops as non-immediate then
+ * we should start checking the cmdsn numbers for mgmt tasks.
+ */
+ if (conn->c_stage == ISCSI_CONN_STARTED &&
+ !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
+ session->queued_cmdsn++;
+ session->cmdsn++;
+ }
+ }
+
+ if (session->tt->init_mgmt_task)
+ session->tt->init_mgmt_task(conn, mtask);
+
+ if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT)
+ session->state = ISCSI_STATE_LOGGING_OUT;
+
+ list_move_tail(&mtask->running, &conn->mgmt_run_list);
+ debug_scsi("mgmtpdu [op 0x%x hdr->itt 0x%x datalen %d]\n",
+ hdr->opcode & ISCSI_OPCODE_MASK, hdr->itt,
+ mtask->data_count);
+ return 0;
+}
+
static struct iscsi_mgmt_task *
__iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
char *data, uint32_t data_size)
@@ -429,6 +481,12 @@
if (!__kfifo_get(session->mgmtpool.queue,
(void*)&mtask, sizeof(void*)))
return NULL;
+
+ if ((hdr->opcode == (ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE)) &&
+ hdr->ttt == RESERVED_ITT) {
+ conn->ping_mtask = mtask;
+ conn->last_ping = jiffies;
+ }
}
if (data_size) {
@@ -440,6 +498,19 @@
memcpy(mtask->hdr, hdr, sizeof(struct iscsi_hdr));
INIT_LIST_HEAD(&mtask->running);
list_add_tail(&mtask->running, &conn->mgmtqueue);
+
+ if (session->tt->caps & CAP_DATA_PATH_OFFLOAD) {
+ if (iscsi_prep_mtask(conn, mtask)) {
+ iscsi_free_mgmt_task(conn, mtask);
+ return NULL;
+ }
+
+ if (session->tt->xmit_mgmt_task(conn, mtask))
+ mtask = NULL;
+
+ } else
+ scsi_queue_work(conn->session->host, &conn->xmitwork);
+
return mtask;
}
@@ -454,7 +525,6 @@
if (!__iscsi_conn_send_pdu(conn, hdr, data, data_size))
err = -EPERM;
spin_unlock_bh(&session->lock);
- scsi_queue_work(session->host, &conn->xmitwork);
return err;
}
EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
@@ -581,17 +651,8 @@
hdr.ttt = RESERVED_ITT;
mtask = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
- if (!mtask) {
+ if (!mtask)
iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
- return;
- }
-
- /* only track our nops */
- if (!rhdr) {
- conn->ping_mtask = mtask;
- conn->last_ping = jiffies;
- }
- scsi_queue_work(conn->session->host, &conn->xmitwork);
}
static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
@@ -868,56 +929,15 @@
}
EXPORT_SYMBOL_GPL(iscsi_conn_failure);
-static void iscsi_prep_mtask(struct iscsi_conn *conn,
- struct iscsi_mgmt_task *mtask)
-{
- struct iscsi_session *session = conn->session;
- struct iscsi_hdr *hdr = mtask->hdr;
- struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;
-
- if (hdr->opcode != (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) &&
- hdr->opcode != (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
- nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
- /*
- * pre-format CmdSN for outgoing PDU.
- */
- nop->cmdsn = cpu_to_be32(session->cmdsn);
- if (hdr->itt != RESERVED_ITT) {
- hdr->itt = build_itt(mtask->itt, session->age);
- /*
- * TODO: We always use immediate, so we never hit this.
- * If we start to send tmfs or nops as non-immediate then
- * we should start checking the cmdsn numbers for mgmt tasks.
- */
- if (conn->c_stage == ISCSI_CONN_STARTED &&
- !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
- session->queued_cmdsn++;
- session->cmdsn++;
- }
- }
-
- if (session->tt->init_mgmt_task)
- session->tt->init_mgmt_task(conn, mtask);
-
- debug_scsi("mgmtpdu [op 0x%x hdr->itt 0x%x datalen %d]\n",
- hdr->opcode & ISCSI_OPCODE_MASK, hdr->itt,
- mtask->data_count);
-}
-
static int iscsi_xmit_mtask(struct iscsi_conn *conn)
{
- struct iscsi_hdr *hdr = conn->mtask->hdr;
int rc;
- if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT)
- conn->session->state = ISCSI_STATE_LOGGING_OUT;
spin_unlock_bh(&conn->session->lock);
-
rc = conn->session->tt->xmit_mgmt_task(conn, conn->mtask);
spin_lock_bh(&conn->session->lock);
if (rc)
return rc;
-
/* done with this in-progress mtask */
conn->mtask = NULL;
return 0;
@@ -961,7 +981,8 @@
* @ctask: ctask to requeue
*
* LLDs that need to run a ctask from the session workqueue should call
- * this. The session lock must be held.
+ * this. The session lock must be held. This should only be called
+ * by software drivers.
*/
void iscsi_requeue_ctask(struct iscsi_cmd_task *ctask)
{
@@ -1013,14 +1034,11 @@
while (!list_empty(&conn->mgmtqueue)) {
conn->mtask = list_entry(conn->mgmtqueue.next,
struct iscsi_mgmt_task, running);
- if (conn->session->state == ISCSI_STATE_LOGGING_OUT) {
+ if (iscsi_prep_mtask(conn, conn->mtask)) {
iscsi_free_mgmt_task(conn, conn->mtask);
conn->mtask = NULL;
continue;
}
-
- iscsi_prep_mtask(conn, conn->mtask);
- list_move_tail(conn->mgmtqueue.next, &conn->mgmt_run_list);
rc = iscsi_xmit_mtask(conn);
if (rc)
goto again;
@@ -1041,9 +1059,6 @@
fail_command(conn, conn->ctask, DID_ABORT << 16);
continue;
}
-
- conn->ctask->state = ISCSI_TASK_RUNNING;
- list_move_tail(conn->xmitqueue.next, &conn->run_list);
rc = iscsi_xmit_ctask(conn);
if (rc)
goto again;
@@ -1192,8 +1207,6 @@
reason = FAILURE_OOM;
goto reject;
}
- session->queued_cmdsn++;
-
sc->SCp.phase = session->age;
sc->SCp.ptr = (char *)ctask;
@@ -1202,11 +1215,26 @@
ctask->conn = conn;
ctask->sc = sc;
INIT_LIST_HEAD(&ctask->running);
-
list_add_tail(&ctask->running, &conn->xmitqueue);
- spin_unlock(&session->lock);
- scsi_queue_work(host, &conn->xmitwork);
+ if (session->tt->caps & CAP_DATA_PATH_OFFLOAD) {
+ if (iscsi_prep_scsi_cmd_pdu(ctask)) {
+ sc->result = DID_ABORT << 16;
+ sc->scsi_done = NULL;
+ iscsi_complete_command(ctask);
+ goto fault;
+ }
+ if (session->tt->xmit_cmd_task(conn, ctask)) {
+ sc->scsi_done = NULL;
+ iscsi_complete_command(ctask);
+ reason = FAILURE_SESSION_NOT_READY;
+ goto reject;
+ }
+ } else
+ scsi_queue_work(session->host, &conn->xmitwork);
+
+ session->queued_cmdsn++;
+ spin_unlock(&session->lock);
spin_lock(host->host_lock);
return 0;
@@ -1225,7 +1253,7 @@
scsi_out(sc)->resid = scsi_out(sc)->length;
scsi_in(sc)->resid = scsi_in(sc)->length;
}
- sc->scsi_done(sc);
+ done(sc);
spin_lock(host->host_lock);
return 0;
}
@@ -1344,7 +1372,6 @@
spin_unlock_bh(&session->lock);
mutex_unlock(&session->eh_mutex);
- scsi_queue_work(session->host, &conn->xmitwork);
/*
* block eh thread until:
@@ -1412,14 +1439,16 @@
void iscsi_suspend_tx(struct iscsi_conn *conn)
{
set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
- scsi_flush_work(conn->session->host);
+ if (!(conn->session->tt->caps & CAP_DATA_PATH_OFFLOAD))
+ scsi_flush_work(conn->session->host);
}
EXPORT_SYMBOL_GPL(iscsi_suspend_tx);
static void iscsi_start_tx(struct iscsi_conn *conn)
{
clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
- scsi_queue_work(conn->session->host, &conn->xmitwork);
+ if (!(conn->session->tt->caps & CAP_DATA_PATH_OFFLOAD))
+ scsi_queue_work(conn->session->host, &conn->xmitwork);
}
static enum scsi_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *scmd)