[SCSI] libiscsi: allow drivers to modify the itt sent to the target

bnx2i and cxgb3i need to encode LLD info in the itt so that
the firmware/hardware can process the pdu. This patch allows
the LLDs to encode info in the task->hdr->itt that they
setup in the alloc_pdu callout (any resources that are allocated
can be freed with the pdu in the cleanup_task callout). If
the LLD encodes info in the itt they should implement a
parse_pdu_itt callout. If parse_pdu_itt is not implemented
libiscsi will do the right thing for the LLD.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 34 insertions, 13 deletions

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index c1bb74052aed..6c4034b1561c 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -222,12 +222,14 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
         struct scsi_cmnd *sc = task->sc;
         struct iscsi_cmd *hdr;
         unsigned hdrlength, cmd_len;
+        itt_t itt;
         int rc;
 
         rc = conn->session->tt->alloc_pdu(task);
         if (rc)
                 return rc;
         hdr = (struct iscsi_cmd *) task->hdr;
+        itt = hdr->itt;
         memset(hdr, 0, sizeof(*hdr));
 
         task->hdr_len = 0;
@@ -238,7 +240,11 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
         hdr->flags = ISCSI_ATTR_SIMPLE;
         int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
         memcpy(task->lun, hdr->lun, sizeof(task->lun));
-        hdr->itt = task->hdr_itt = build_itt(task->itt, session->age);
+        if (session->tt->parse_pdu_itt)
+                hdr->itt = task->hdr_itt = itt;
+        else
+                hdr->itt = task->hdr_itt = build_itt(task->itt,
+                                                     task->conn->session->age);
         hdr->cmdsn = task->cmdsn = cpu_to_be32(session->cmdsn);
         session->cmdsn++;
         hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
@@ -457,7 +463,6 @@ static int iscsi_prep_mgmt_task(struct iscsi_conn *conn,
          */
         nop->cmdsn = cpu_to_be32(session->cmdsn);
         if (hdr->itt != RESERVED_ITT) {
-                hdr->itt = build_itt(task->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
@@ -490,6 +495,7 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 {
         struct iscsi_session *session = conn->session;
         struct iscsi_task *task;
+        itt_t itt;
 
         if (session->state == ISCSI_STATE_TERMINATE)
                 return NULL;
@@ -531,9 +537,18 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                                  "pdu for mgmt task.\n");
                 goto requeue_task;
         }
+        itt = task->hdr->itt;
         task->hdr_len = sizeof(struct iscsi_hdr);
-
         memcpy(task->hdr, hdr, sizeof(struct iscsi_hdr));
+
+        if (hdr->itt != RESERVED_ITT) {
+                if (session->tt->parse_pdu_itt)
+                        task->hdr->itt = itt;
+                else
+                        task->hdr->itt = build_itt(task->itt,
+                                                   task->conn->session->age);
+        }
+
         INIT_LIST_HEAD(&task->running);
         list_add_tail(&task->running, &conn->mgmtqueue);
 
@@ -745,7 +760,6 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 {
         struct iscsi_reject *reject = (struct iscsi_reject *)hdr;
         struct iscsi_hdr rejected_pdu;
-        uint32_t itt;
 
         conn->exp_statsn = be32_to_cpu(reject->statsn) + 1;
 
@@ -755,10 +769,9 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 
                 if (ntoh24(reject->dlength) >= sizeof(struct iscsi_hdr)) {
                         memcpy(&rejected_pdu, data, sizeof(struct iscsi_hdr));
-                        itt = get_itt(rejected_pdu.itt);
                         iscsi_conn_printk(KERN_ERR, conn,
-                                          "itt 0x%x had pdu (op 0x%x) rejected "
-                                          "due to DataDigest error.\n", itt,
+                                          "pdu (op 0x%x) rejected "
+                                          "due to DataDigest error.\n",
                                           rejected_pdu.opcode);
                 }
         }
@@ -778,12 +791,15 @@ static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 static struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *conn, itt_t itt)
 {
         struct iscsi_session *session = conn->session;
-        uint32_t i;
+        int i;
 
         if (itt == RESERVED_ITT)
                 return NULL;
 
-        i = get_itt(itt);
+        if (session->tt->parse_pdu_itt)
+                session->tt->parse_pdu_itt(conn, itt, &i, NULL);
+        else
+                i = get_itt(itt);
         if (i >= session->cmds_max)
                 return NULL;
 
@@ -958,20 +974,25 @@ EXPORT_SYMBOL_GPL(iscsi_complete_pdu);
 int iscsi_verify_itt(struct iscsi_conn *conn, itt_t itt)
 {
         struct iscsi_session *session = conn->session;
-        uint32_t i;
+        int age = 0, i = 0;
 
         if (itt == RESERVED_ITT)
                 return 0;
 
-        if (((__force u32)itt & ISCSI_AGE_MASK) !=
-            (session->age << ISCSI_AGE_SHIFT)) {
+        if (session->tt->parse_pdu_itt)
+                session->tt->parse_pdu_itt(conn, itt, &i, &age);
+        else {
+                i = get_itt(itt);
+                age = ((__force u32)itt >> ISCSI_AGE_SHIFT) & ISCSI_AGE_MASK;
+        }
+
+        if (age != session->age) {
                 iscsi_conn_printk(KERN_ERR, conn,
                                   "received itt %x expected session age (%x)\n",
                                   (__force u32)itt, session->age);
                 return ISCSI_ERR_BAD_ITT;
         }
 
-        i = get_itt(itt);
         if (i >= session->cmds_max) {
                 iscsi_conn_printk(KERN_ERR, conn,
                                   "received invalid itt index %u (max cmds "