On 3/17/26 13:06, John Garry wrote:
Add a core equivalent of alua_stpg() from scsi_dh_alua.c
Signed-off-by: John Garry <[email protected]>
---
drivers/scsi/scsi_alua.c | 99 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 99 insertions(+)
diff --git a/drivers/scsi/scsi_alua.c b/drivers/scsi/scsi_alua.c
index 50c1d17b52dc7..1045885f74169 100644
--- a/drivers/scsi/scsi_alua.c
+++ b/drivers/scsi/scsi_alua.c
@@ -30,6 +30,9 @@ static struct workqueue_struct *kalua_wq;
#define RTPG_FMT_MASK 0x70
#define RTPG_FMT_EXT_HDR 0x10
+#define TPGS_MODE_NONE 0x0
+#define TPGS_MODE_IMPLICIT 0x1
+#define TPGS_MODE_EXPLICIT 0x2
#define ALUA_RTPG_SIZE 128
#define ALUA_FAILOVER_TIMEOUT 60
@@ -65,6 +68,41 @@ static int submit_rtpg(struct scsi_device *sdev, unsigned
char *buff,
ALUA_FAILOVER_RETRIES, &exec_args);
}
+/*
+ * submit_stpg - Issue a SET TARGET PORT GROUP command
+ *
+ * Currently we're only setting the current target port group state
+ * to 'active/optimized' and let the array firmware figure out
+ * the states of the remaining groups.
+ */
+static int submit_stpg(struct scsi_device *sdev,
+ struct scsi_sense_hdr *sshdr)
+{
+ u8 cdb[MAX_COMMAND_SIZE];
+ unsigned char stpg_data[8];
+ int stpg_len = 8;
+ blk_opf_t opf = REQ_OP_DRV_OUT | REQ_FAILFAST_DEV |
+ REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
+ const struct scsi_exec_args exec_args = {
+ .sshdr = sshdr,
+ };
+
+ /* Prepare the data buffer */
+ memset(stpg_data, 0, stpg_len);
+ stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL;
+ put_unaligned_be16(sdev->alua->group_id, &stpg_data[6]);
+
+ /* Prepare the command. */
+ memset(cdb, 0x0, MAX_COMMAND_SIZE);
+ cdb[0] = MAINTENANCE_OUT;
+ cdb[1] = MO_SET_TARGET_PGS;
+ put_unaligned_be32(stpg_len, &cdb[6]);
+
+ return scsi_execute_cmd(sdev, cdb, opf, stpg_data,
+ stpg_len, ALUA_FAILOVER_TIMEOUT * HZ,
+ ALUA_FAILOVER_RETRIES, &exec_args);
+}
+
static char print_alua_state(unsigned char state)
{
switch (state) {
@@ -326,6 +364,67 @@ static int scsi_alua_rtpg(struct scsi_device *sdev)
return err;
}
+
+/*
+ * scsi_alua_stpg - Issue a SET TARGET PORT GROUP command
+ *
+ * Issue a SET TARGET PORT GROUP command and evaluate the
+ * response. Returns SCSI_DH_RETRY per default to trigger
+ * a re-evaluation of the target group state or SCSI_DH_OK
+ * if no further action needs to be taken.
+ */
+__maybe_unused
+static int scsi_alua_stpg(struct scsi_device *sdev, bool optimize)
+{
+ struct alua_data *alua = sdev->alua;
+ int retval;
+ struct scsi_sense_hdr sense_hdr;
+
+ if (!(alua->tpgs & TPGS_MODE_EXPLICIT)) {
+ /* Only implicit ALUA supported, retry */
+ return -EAGAIN;//SCSI_DH_RETRY;
+ }
+ switch (alua->state) {
+ case SCSI_ACCESS_STATE_OPTIMAL:
+ return 0;//SCSI_DH_OK;
+ case SCSI_ACCESS_STATE_ACTIVE:
+ if (optimize &&
+ !alua->pref &&
+ (alua->tpgs & TPGS_MODE_IMPLICIT))
+ return 0;//SCSI_DH_OK;
+ break;
+ case SCSI_ACCESS_STATE_STANDBY:
+ case SCSI_ACCESS_STATE_UNAVAILABLE:
+ break;
+ case SCSI_ACCESS_STATE_OFFLINE:
+ return -EIO;//SCSI_DH_IO;
+ case SCSI_ACCESS_STATE_TRANSITIONING:
+ break;
+ default:
+ sdev_printk(KERN_INFO, sdev,
+ "%s: stpg failed, unhandled TPGS state %d",
+ DRV_NAME, alua->state);
+ return -ENOSYS ;//SCSI_DH_NOSYS;
+ }
+ retval = submit_stpg(sdev, &sense_hdr);
+
+ if (retval) {
+ if (retval < 0 || !scsi_sense_valid(&sense_hdr)) {
+ sdev_printk(KERN_INFO, sdev,
+ "%s: stpg failed, result %d",
+ DRV_NAME, retval);
+ if (retval < 0)
+ return -EBUSY;//SCSI_DH_DEV_TEMP_BUSY;
+ } else {
+ sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n",
+ DRV_NAME);
+ scsi_print_sense_hdr(sdev, DRV_NAME, &sense_hdr);
+ }
+ }
+ /* Retry RTPG */
+ return -EAGAIN;//SCSI_DH_RETRY;
+}
+
int scsi_alua_sdev_init(struct scsi_device *sdev)
{
int rel_port, ret, tpgs;
Hmm. The return code from alus_stpg() was really an internal thing in
scsi_dh_alua to drive the state machine.
I'd rather have _this_ function to use normal syntax (ie return '0' on
success), and modify the state machine in scsi_dh_alua accordingly.
Note: stpg handling should be done _only_ in scsi_dh_alua. The scsi
core should not attempt anything clever here.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
[email protected] +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
