iscsi-target: Disable Immediate + Unsolicited Data with ISER Protection

This patch explicitly disables Immediate + Unsolicited Data for ISER
connections during login in iscsi_login_zero_tsih_s2() when protection
has been enabled for the session by the underlying hardware.

This is currently required because protection / signature memory regions
(MRs) expect T10 PI to occur on RDMA READs + RDMA WRITEs transfers, and
not on a immediate data payload associated with ISCSI_OP_SCSI_CMD, or
unsolicited data-out associated with a ISCSI_OP_SCSI_DATA_OUT.

v2 changes:
  - Add TARGET_PROT_DOUT_INSERT check (Sagi)
  - Add pr_debug noisemaker (Sagi)
  - Add goto to avoid early return from MRDSL check (nab)

Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index b72d8550e8bc71e5473a5a2ac0458d89fbe15477..ca31fa1b8a4b69058290243bc61b0007d2c7d3cc 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -436,7 +436,7 @@ static int iscsi_login_zero_tsih_s2(
                }
                off = mrdsl % PAGE_SIZE;
                if (!off)
-                       return 0;
+                       goto check_prot;
 
                if (mrdsl < PAGE_SIZE)
                        mrdsl = PAGE_SIZE;
@@ -452,6 +452,31 @@ static int iscsi_login_zero_tsih_s2(
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                        return -1;
                }
+               /*
+                * ISER currently requires that ImmediateData + Unsolicited
+                * Data be disabled when protection / signature MRs are enabled.
+                */
+check_prot:
+               if (sess->se_sess->sup_prot_ops &
+                  (TARGET_PROT_DOUT_STRIP | TARGET_PROT_DOUT_PASS |
+                   TARGET_PROT_DOUT_INSERT)) {
+
+                       sprintf(buf, "ImmediateData=No");
+                       if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
+                               iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
+                                                   ISCSI_LOGIN_STATUS_NO_RESOURCES);
+                               return -1;
+                       }
+
+                       sprintf(buf, "InitialR2T=Yes");
+                       if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
+                               iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
+                                                   ISCSI_LOGIN_STATUS_NO_RESOURCES);
+                               return -1;
+                       }
+                       pr_debug("Forcing ImmediateData=No + InitialR2T=Yes for"
+                                " T10-PI enabled ISER session\n");
+               }
        }
 
        return 0;