s390/dasd: add query PPRC function

Add function to query the Peer-to-Peer-Remote-Copy (PPRC) state of a
device by reading the related structure through a read subsystem data call.

Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Link: https://lore.kernel.org/r/20220920192616.808070-3-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/s390/block/dasd_eckd.c

@@ -6086,6 +6086,71 @@ static int dasd_hosts_print(struct dasd_device *device, struct seq_file *m)
 	return 0;
 }
 
+/*
+ * Perform Subsystem Function - Peer-to-Peer Remote Copy Extended Query
+ */
+static int dasd_eckd_query_pprc_status(struct dasd_device *device,
+				       struct dasd_pprc_data_sc4 *data)
+{
+	struct dasd_pprc_data_sc4 *pprc_data;
+	struct dasd_psf_prssd_data *prssdp;
+	struct dasd_ccw_req *cqr;
+	struct ccw1 *ccw;
+	int rc;
+
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */	+ 1 /* RSSD */,
+				   sizeof(*prssdp) + sizeof(*pprc_data) + 1,
+				   device, NULL);
+	if (IS_ERR(cqr)) {
+		DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
+				"Could not allocate query PPRC status request");
+		return PTR_ERR(cqr);
+	}
+	cqr->startdev = device;
+	cqr->memdev = device;
+	cqr->block = NULL;
+	cqr->retries = 256;
+	cqr->expires = 10 * HZ;
+
+	/* Prepare for Read Subsystem Data */
+	prssdp = (struct dasd_psf_prssd_data *)cqr->data;
+	memset(prssdp, 0, sizeof(struct dasd_psf_prssd_data));
+	prssdp->order = PSF_ORDER_PRSSD;
+	prssdp->suborder = PSF_SUBORDER_PPRCEQ;
+	prssdp->varies[0] = PPRCEQ_SCOPE_4;
+	pprc_data = (struct dasd_pprc_data_sc4 *)(prssdp + 1);
+
+	ccw = cqr->cpaddr;
+	ccw->cmd_code = DASD_ECKD_CCW_PSF;
+	ccw->count = sizeof(struct dasd_psf_prssd_data);
+	ccw->flags |= CCW_FLAG_CC;
+	ccw->flags |= CCW_FLAG_SLI;
+	ccw->cda = (__u32)(addr_t)prssdp;
+
+	/* Read Subsystem Data - query host access */
+	ccw++;
+	ccw->cmd_code = DASD_ECKD_CCW_RSSD;
+	ccw->count = sizeof(*pprc_data);
+	ccw->flags |= CCW_FLAG_SLI;
+	ccw->cda = (__u32)(addr_t)pprc_data;
+
+	cqr->buildclk = get_tod_clock();
+	cqr->status = DASD_CQR_FILLED;
+
+	rc = dasd_sleep_on_interruptible(cqr);
+	if (rc == 0) {
+		*data = *pprc_data;
+	} else {
+		DBF_EVENT_DEVID(DBF_WARNING, device->cdev,
+				"PPRC Extended Query failed with rc=%d\n",
+				rc);
+		rc = -EOPNOTSUPP;
+	}
+
+	dasd_sfree_request(cqr, cqr->memdev);
+	return rc;
+}
+
 /*
  * Perform Subsystem Function - CUIR response
  */
@@ -6705,6 +6770,7 @@ static struct dasd_discipline dasd_eckd_discipline = {
 	.ext_pool_exhaust = dasd_eckd_ext_pool_exhaust,
 	.ese_format = dasd_eckd_ese_format,
 	.ese_read = dasd_eckd_ese_read,
+	.pprc_status = dasd_eckd_query_pprc_status,
 };
 
 static int __init

drivers/s390/block/dasd_eckd.h

@@ -66,9 +66,15 @@
  * Perform Subsystem Function / Sub-Orders
  */
 #define PSF_SUBORDER_QHA		 0x1C /* Query Host Access */
+#define PSF_SUBORDER_PPRCEQ		 0x50 /* PPRC Extended Query */
 #define PSF_SUBORDER_VSQ		 0x52 /* Volume Storage Query */
 #define PSF_SUBORDER_LCQ		 0x53 /* Logical Configuration Query */
 
+/*
+ * PPRC Extended Query Scopes
+ */
+#define PPRCEQ_SCOPE_4			 0x04 /* Scope 4 for PPRC Extended Query */
+
 /*
  * CUIR response condition codes
  */

drivers/s390/block/dasd_int.h

@@ -259,6 +259,37 @@ struct dasd_uid {
 	char vduit[33];
 };
 
+/*
+ * PPRC Status data
+ */
+struct dasd_pprc_header {
+	__u8 entries;		/* 0     Number of device entries */
+	__u8 unused;		/* 1     unused */
+	__u16 entry_length;	/* 2-3   Length of device entry */
+	__u32 unused2;		/* 4-7   unused */
+} __packed;
+
+struct dasd_pprc_dev_info {
+	__u8 state;		/* 0       Copy State */
+	__u8 flags;		/* 1       Flags */
+	__u8 reserved1[2];	/* 2-3     reserved */
+	__u8 prim_lss;		/* 4       Primary device LSS */
+	__u8 primary;		/* 5       Primary device address */
+	__u8 sec_lss;		/* 6       Secondary device LSS */
+	__u8 secondary;		/* 7       Secondary device address */
+	__u16 pprc_id;		/* 8-9     Peer-to-Peer Remote Copy ID */
+	__u8 reserved2[12];	/* 10-21   reserved */
+	__u16 prim_cu_ssid;	/* 22-23   Pimary Control Unit SSID */
+	__u8 reserved3[12];	/* 24-35   reserved */
+	__u16 sec_cu_ssid;	/* 36-37   Secondary Control Unit SSID */
+	__u8 reserved4[90];	/* 38-127  reserved */
+} __packed;
+
+struct dasd_pprc_data_sc4 {
+	struct dasd_pprc_header header;
+	struct dasd_pprc_dev_info dev_info[5];
+} __packed;
+
 /*
  * the struct dasd_discipline is
  * sth like a table of virtual functions, if you think of dasd_eckd
@@ -387,6 +418,7 @@ struct dasd_discipline {
 	struct dasd_ccw_req *(*ese_format)(struct dasd_device *,
 					   struct dasd_ccw_req *, struct irb *);
 	int (*ese_read)(struct dasd_ccw_req *, struct irb *);
+	int (*pprc_status)(struct dasd_device *, struct	dasd_pprc_data_sc4 *);
 };
 
 extern struct dasd_discipline *dasd_diag_discipline_pointer;