scsi: scsi_debug: Implement the IO Advice Hints Grouping mode page

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>
Link: https://lore.kernel.org/r/20240130214911.1863909-18-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index b544498..ccf59b3 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1969,7 +1969,11 @@ 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 */
@@ -2559,6 +2563,40 @@ 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 */
@@ -2708,6 +2746,10 @@ 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)
@@ -2742,9 +2784,20 @@ 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 */
@@ -2778,6 +2831,8 @@ 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,