target: Add MI_REPORT_TARGET_PGS ext. header + implict_trans_secs attribute

This patch adds support for ALUA MI_REPORT_TARGET_PGS extended header
format defined within SPC-4.  It changes target core ALUA emulation logic
within target_emulate_report_target_port_groups() to support both the
extended and original length only header formats.

It includes adding a new 'implict_trans_secs' attribute for each ALUA
target port group to control the value returned to the application client
for an recommended implict translation timeout in seconds.  By default
this value is currently set to zero, and limited up to 255 by virtue of
using a single byte in the extended header format.

This value is used by target_emulate_report_target_port_groups() within
the extended header logic to set IMPLICIT TRANSITION TIME as defined by
spc4r30.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Rob Evers <revers@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 1fe9111f4dc1..dc35d8660aa6 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -330,6 +330,7 @@ struct t10_alua_tg_pt_gp {
         int     tg_pt_gp_alua_access_type;
         int     tg_pt_gp_nonop_delay_msecs;
         int     tg_pt_gp_trans_delay_msecs;
+        int     tg_pt_gp_implict_trans_secs;
         int     tg_pt_gp_pref;
         int     tg_pt_gp_write_metadata;
         /* Used by struct t10_alua_tg_pt_gp->tg_pt_gp_md_buf_len */