From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch adds a new target_core_fabric_ops callback for allowing fabric
drivers to expose a TPG attribute for signaling when a T10-PI protected
fabric wants to function with an un-protected device without T10-PI.
This specifically is to allow LIO to perform WRITE_STRIP + READ_INSERT
operations when functioning with non T10-PI enabled devices, seperate
from any available hw offloads the fabric supports.
This is done using a new se_sess->sess_prot_type that is set at fabric
session creation time based upon the TPG attribute. It currently cannot
be changed for individual sessions after initial creation.
Also, update existing target_core_sbc.c code to honor sess_prot_type when
setting up cmd->prot_op + cmd->prot_type assignments.
Cc: Martin Petersen <martin.petersen@xxxxxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Doug Gilbert <dgilbert@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_sbc.c | 44 +++++++++++++++++++++++++---------
drivers/target/target_core_transport.c | 8 +++++++
include/target/target_core_base.h | 1 +
include/target/target_core_fabric.h | 8 +++++++
4 files changed, 50 insertions(+), 11 deletions(-)
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 95a7a74..5b3564a 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -581,12 +581,13 @@ sbc_compare_and_write(struct se_cmd *cmd)
}
static int
-sbc_set_prot_op_checks(u8 protect, enum target_prot_type prot_type,
+sbc_set_prot_op_checks(u8 protect, bool fabric_prot, enum target_prot_type prot_type,
bool is_write, struct se_cmd *cmd)
{
if (is_write) {
- cmd->prot_op = protect ? TARGET_PROT_DOUT_PASS :
- TARGET_PROT_DOUT_INSERT;
+ cmd->prot_op = fabric_prot ? TARGET_PROT_DOUT_STRIP :
+ protect ? TARGET_PROT_DOUT_PASS :
+ TARGET_PROT_DOUT_INSERT;
switch (protect) {
case 0x0:
case 0x3:
@@ -610,8 +611,9 @@ sbc_set_prot_op_checks(u8 protect, enum target_prot_type prot_type,
return -EINVAL;
}
} else {
- cmd->prot_op = protect ? TARGET_PROT_DIN_PASS :
- TARGET_PROT_DIN_STRIP;
+ cmd->prot_op = fabric_prot ? TARGET_PROT_DIN_INSERT :
+ protect ? TARGET_PROT_DIN_PASS :
+ TARGET_PROT_DIN_STRIP;
switch (protect) {
case 0x0:
case 0x1:
@@ -644,11 +646,15 @@ sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
u32 sectors, bool is_write)
{
u8 protect = cdb[1] >> 5;
+ int sp_ops = cmd->se_sess->sup_prot_ops;
+ int pi_prot_type = dev->dev_attrib.pi_prot_type;
+ bool fabric_prot = false;
if (!cmd->t_prot_sg || !cmd->t_prot_nents) {
- if (protect && !dev->dev_attrib.pi_prot_type) {
- pr_err("CDB contains protect bit, but device does not"
- " advertise PROTECT=1 feature bit\n");
+ if (protect &&
+ !dev->dev_attrib.pi_prot_type && !cmd->se_sess->sess_prot_type) {
+ pr_err("CDB contains protect bit, but device + fabric does"
+ " not advertise PROTECT=1 feature bit\n");
return TCM_INVALID_CDB_FIELD;
}
if (cmd->prot_pto)
@@ -669,15 +675,28 @@ sbc_check_prot(struct se_device *dev, struct se_cmd *cmd, unsigned char *cdb,
cmd->reftag_seed = cmd->t_task_lba;
break;
case TARGET_DIF_TYPE0_PROT:
+ /*
+ * See if the fabric supports T10-PI, and the session has been
+ * configured to allow export PROTECT=1 feature bit with backend
+ * devices that don't support T10-PI.
+ */
+ fabric_prot = is_write ?
+ (sp_ops & (TARGET_PROT_DOUT_PASS | TARGET_PROT_DOUT_STRIP)) :
+ (sp_ops & (TARGET_PROT_DIN_PASS | TARGET_PROT_DIN_INSERT));
+
+ if (fabric_prot && cmd->se_sess->sess_prot_type) {
+ pi_prot_type = cmd->se_sess->sess_prot_type;
+ break;
+ }
+ /* Fallthrough */
default:
return TCM_NO_SENSE;
}
- if (sbc_set_prot_op_checks(protect, dev->dev_attrib.pi_prot_type,
- is_write, cmd))
+ if (sbc_set_prot_op_checks(protect, fabric_prot, pi_prot_type, is_write, cmd))
return TCM_INVALID_CDB_FIELD;
- cmd->prot_type = dev->dev_attrib.pi_prot_type;
+ cmd->prot_type = pi_prot_type;
cmd->prot_length = dev->prot_length * sectors;
/**
@@ -1231,6 +1250,9 @@ sbc_dif_copy_prot(struct se_cmd *cmd, unsigned int sectors, bool read,
unsigned int i, len, left;
unsigned int offset = sg_off;
+ if (!sg)
+ return;
+
left = sectors * dev->prot_length;
for_each_sg(cmd->t_prot_sg, psg, cmd->t_prot_nents, i) {
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index ac3cbab..38d9d1b 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -322,11 +322,19 @@ void __transport_register_session(
struct se_session *se_sess,
void *fabric_sess_ptr)
{
+ struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
unsigned char buf[PR_REG_ISID_LEN];
se_sess->se_tpg = se_tpg;
se_sess->fabric_sess_ptr = fabric_sess_ptr;
/*
+ * Determine if fabric allows for T10-PI feature bits to be exposed
+ * to initiators for device backends with !dev->dev_attrib.pi_prot_type
+ */
+ if (tfo->tpg_check_prot_fabric_only)
+ se_sess->sess_prot_type = tfo->tpg_check_prot_fabric_only(se_tpg);
+
+ /*
* Used by struct se_node_acl's under ConfigFS to locate active se_session-t
*
* Only set for struct se_session's that will actually be moving I/O.
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 672150b..fe25a78 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -616,6 +616,7 @@ struct se_session {
unsigned sess_tearing_down:1;
u64 sess_bin_isid;
enum target_prot_op sup_prot_ops;
+ enum target_prot_type sess_prot_type;
struct se_node_acl *se_node_acl;
struct se_portal_group *se_tpg;
void *fabric_sess_ptr;
diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 22a4e98e..9811c85 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -27,6 +27,14 @@ struct target_core_fabric_ops {
* inquiry response
*/
int (*tpg_check_demo_mode_login_only)(struct se_portal_group *);
+ /*
+ * Optionally used as a configfs tunable to determine when
+ * target-core should signal the PROTECT=1 feature bit for
+ * backends that don't support T10-PI, so that either fabric
+ * HW offload or target-core emulation performs the associated
+ * WRITE_STRIP and READ_INSERT operations.
+ */
+ int (*tpg_check_prot_fabric_only)(struct se_portal_group *);
struct se_node_acl *(*tpg_alloc_fabric_acl)(
struct se_portal_group *);
void (*tpg_release_fabric_acl)(struct se_portal_group *,
--
1.9.1
--
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