[PATCH v8 17/19] scsi: scsi_debug: Implement the IO Advice Hints Grouping mode page

Bart Van Assche
2023-12-19T00:09:03Z

Implement an IO Advice Hints Grouping mode page with three permanent
streams. A permanent stream is a stream for which the device server does
not allow closing or otherwise modifying the configuration of that
stream. The stream identifier enable (ST_ENBLE) bit specifies whether
the stream identifier may be used in the GROUP NUMBER field of SCSI
WRITE commands.

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/scsi/scsi_debug.c | 61 +++++++++++++++++++++++++++++++++++++--
1 file changed, 58 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 4181d0d81224..4e18265a05da 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1975,7 +1975,11 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
arr[4] = 0x5; /* SPT: GRD_CHK:1, REF_CHK:1 */
else
arr[4] = 0x0; /* no protection stuff */
- arr[5] = 0x7; /* head of q, ordered + simple q's */
+ /*
+ * GROUP_SUP=1; HEADSUP=1 (HEAD OF QUEUE); ORDSUP=1
+ * (ORDERED queuing); SIMPSUP=1 (SIMPLE queuing).
+ */
+ arr[5] = 0x17;
} else if (0x87 == cmd[2]) { /* mode page policy */
arr[3] = 0x8; /* number of following entries */
arr[4] = 0x2; /* disconnect-reconnect mp */
@@ -2565,6 +2569,40 @@ static int resp_ctrl_m_pg(unsigned char *p, int pcontrol, int target)
return sizeof(ctrl_m_pg);
}

+/* IO Advice Hints Grouping mode page */
+static int resp_grouping_m_pg(unsigned char *p, int pcontrol, int target)
+{
+ /* IO Advice Hints Grouping mode page */
+ struct grouping_m_pg {
+ u8 page_code; /* OR 0x40 when subpage_code > 0 */
+ u8 subpage_code;
+ __be16 page_length;
+ u8 reserved[12];
+ struct scsi_io_group_descriptor descr[MAXIMUM_NUMBER_OF_STREAMS];
+ };
+ static const struct grouping_m_pg gr_m_pg = {
+ .page_code = 0xa | 0x40,
+ .subpage_code = 5,
+ .page_length = cpu_to_be16(sizeof(gr_m_pg) - 4),
+ .descr = {
+ { .st_enble = 1 },
+ { .st_enble = 1 },
+ { .st_enble = 1 },
+ { .st_enble = 1 },
+ { .st_enble = 1 },
+ { .st_enble = 0 },
+ }
+ };
+
+ BUILD_BUG_ON(sizeof(struct grouping_m_pg) !=
+ 16 + MAXIMUM_NUMBER_OF_STREAMS * 16);
+ memcpy(p, &gr_m_pg, sizeof(gr_m_pg));
+ if (1 == pcontrol) {
+ /* There are no changeable values so clear from byte 4 on. */
+ memset(p + 4, 0, sizeof(gr_m_pg) - 4);
+ }
+ return sizeof(gr_m_pg);
+}

static int resp_iec_m_pg(unsigned char *p, int pcontrol, int target)
{ /* Informational Exceptions control mode page for mode_sense */
@@ -2714,6 +2752,10 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
ap = arr + offset;
}

+ /*
+ * N.B. If len>0 before resp_*_pg() call, then form of that call should be:
+ * len += resp_*_pg(ap + len, pcontrol, target);
+ */
switch (pcode) {
case 0x1: /* Read-Write error recovery page, direct access */
if (subpcode > 0x0 && subpcode < 0xff)
@@ -2748,9 +2790,20 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
}
break;
case 0xa: /* Control Mode page, all devices */
- if (subpcode > 0x0 && subpcode < 0xff)
+ switch (subpcode) {
+ case 0:
+ len = resp_ctrl_m_pg(ap, pcontrol, target);
+ break;
+ case 0x05:
+ len = resp_grouping_m_pg(ap, pcontrol, target);
+ break;
+ case 0xff:
+ len = resp_ctrl_m_pg(ap, pcontrol, target);
+ len += resp_grouping_m_pg(ap + len, pcontrol, target);
+ break;
+ default:
goto bad_subpcode;
- len = resp_ctrl_m_pg(ap, pcontrol, target);
+ }
offset += len;
break;
case 0x19: /* if spc==1 then sas phy, control+discover */
@@ -2784,6 +2837,8 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
len += resp_caching_pg(ap + len, pcontrol, target);
}
len += resp_ctrl_m_pg(ap + len, pcontrol, target);
+ if (0xff == subpcode)
+ len += resp_grouping_m_pg(ap + len, pcontrol, target);
len += resp_sas_sf_m_pg(ap + len, pcontrol, target);
if (0xff == subpcode) {
len += resp_sas_pcd_m_spg(ap + len, pcontrol, target,