target: Update SPC/SBC emulation for sess_prot_type

This patch updates standard INQUIRY, INQUIRY EVPD=0x86, READ_CAPACITY_16
and control mode pages to use se_sess->sess_prot_type when determing which
type of T10-PI related feature bits can be exposed.

This is required for fabric sessions supporting T10-PI metadata to
backend devices that don't have protection enabled.

Reviewed-by: Martin Petersen <martin.petersen@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Doug Gilbert <dgilbert@interlog.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 20 insertions, 7 deletions

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 9efd1fd985ee..67bc1886f004 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -93,6 +93,8 @@ sbc_emulate_readcapacity_16(struct se_cmd *cmd)
 {
         struct se_device *dev = cmd->se_dev;
         struct se_session *sess = cmd->se_sess;
+        int pi_prot_type = dev->dev_attrib.pi_prot_type;
+
         unsigned char *rbuf;
         unsigned char buf[32];
         unsigned long long blocks = dev->transport->get_blocks(dev);
@@ -114,8 +116,15 @@ sbc_emulate_readcapacity_16(struct se_cmd *cmd)
          * Set P_TYPE and PROT_EN bits for DIF support
          */
         if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
-                if (dev->dev_attrib.pi_prot_type)
-                        buf[12] = (dev->dev_attrib.pi_prot_type - 1) << 1 | 0x1;
+                /*
+                 * Only override a device's pi_prot_type if no T10-PI is
+                 * available, and sess_prot_type has been explicitly enabled.
+                 */
+                if (!pi_prot_type)
+                        pi_prot_type = sess->sess_prot_type;
+
+                if (pi_prot_type)
+                        buf[12] = (pi_prot_type - 1) << 1 | 0x1;
         }
 
         if (dev->transport->get_lbppbe)
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c
index f310aac38bd8..9ec64596588c 100644
--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -103,10 +103,12 @@ spc_emulate_inquiry_std(struct se_cmd *cmd, unsigned char *buf)
                 buf[5] |= 0x8;
         /*
          * Set Protection (PROTECT) bit when DIF has been enabled on the
-         * device, and the transport supports VERIFY + PASS.
+         * device, and the fabric supports VERIFY + PASS.  Also report
+         * PROTECT=1 if sess_prot_type has been configured to allow T10-PI
+         * to unprotected devices.
          */
         if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
-                if (dev->dev_attrib.pi_prot_type)
+                if (dev->dev_attrib.pi_prot_type || cmd->se_sess->sess_prot_type)
                         buf[5] |= 0x1;
         }
 
@@ -480,9 +482,11 @@ spc_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
          * only for TYPE3 protection.
          */
         if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
-                if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT)
+                if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE1_PROT ||
+                    cmd->se_sess->sess_prot_type == TARGET_DIF_TYPE1_PROT)
                         buf[4] = 0x5;
-                else if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE3_PROT)
+                else if (dev->dev_attrib.pi_prot_type == TARGET_DIF_TYPE3_PROT ||
+                        cmd->se_sess->sess_prot_type == TARGET_DIF_TYPE3_PROT)
                         buf[4] = 0x4;
         }
 
@@ -874,7 +878,7 @@ static int spc_modesense_control(struct se_cmd *cmd, u8 pc, u8 *p)
          * TAG field.
          */
         if (sess->sup_prot_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DOUT_PASS)) {
-                if (dev->dev_attrib.pi_prot_type)
+                if (dev->dev_attrib.pi_prot_type || sess->sess_prot_type)
                         p[5] |= 0x80;
         }