[S390] cio: notify drivers of channel path events

This patch adds a notification mechanism to inform ccw drivers
about changes to channel paths, which occured while the device
is online.

Signed-off-by: Sebastian Ott <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/ccwdev.h

···
 };
 
 /*
+ * Possible events used by the path_event notifier.
+ */
+#define PE_NONE				0x0
+#define PE_PATH_GONE			0x1 /* A path is no longer available. */
+#define PE_PATH_AVAILABLE		0x2 /* A path has become available and
+					       was successfully verified. */
+#define PE_PATHGROUP_ESTABLISHED	0x4 /* A pathgroup was reset and had
+					       to be established again. */
+
+/*
  * Possible CIO actions triggered by the unit check handler.
  */
 enum uc_todo {
···
  * @set_online: called when setting device online
  * @set_offline: called when setting device offline
  * @notify: notify driver of device state changes
+ * @path_event: notify driver of channel path events
  * @shutdown: called at device shutdown
  * @prepare: prepare for pm state transition
  * @complete: undo work done in @prepare
···
 	int (*set_online) (struct ccw_device *);
 	int (*set_offline) (struct ccw_device *);
 	int (*notify) (struct ccw_device *, int);
+	void (*path_event) (struct ccw_device *, int *);
 	void (*shutdown) (struct ccw_device *);
 	int (*prepare) (struct ccw_device *);
 	void (*complete) (struct ccw_device *);

drivers/s390/cio/device.c

···
 static int io_subchannel_chp_event(struct subchannel *sch,
 				   struct chp_link *link, int event)
 {
+	struct ccw_device *cdev = sch_get_cdev(sch);
 	int mask;
 
 	mask = chp_ssd_get_mask(&sch->ssd_info, link);
···
 	case CHP_VARY_OFF:
 		sch->opm &= ~mask;
 		sch->lpm &= ~mask;
+		if (cdev)
+			cdev->private->path_gone_mask |= mask;
 		io_subchannel_terminate_path(sch, mask);
 		break;
 	case CHP_VARY_ON:
 		sch->opm |= mask;
 		sch->lpm |= mask;
+		if (cdev)
+			cdev->private->path_new_mask |= mask;
 		io_subchannel_verify(sch);
 		break;
 	case CHP_OFFLINE:
 		if (cio_update_schib(sch))
 			return -ENODEV;
+		if (cdev)
+			cdev->private->path_gone_mask |= mask;
 		io_subchannel_terminate_path(sch, mask);
 		break;
 	case CHP_ONLINE:
 		if (cio_update_schib(sch))
 			return -ENODEV;
 		sch->lpm |= mask & sch->opm;
+		if (cdev)
+			cdev->private->path_new_mask |= mask;
 		io_subchannel_verify(sch);
 		break;
 	}

drivers/s390/cio/device_fsm.c

···
 
 static void ccw_device_oper_notify(struct ccw_device *cdev)
 {
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+
 	if (ccw_device_notify(cdev, CIO_OPER) == NOTIFY_OK) {
 		/* Reenable channel measurements, if needed. */
 		ccw_device_sched_todo(cdev, CDEV_TODO_ENABLE_CMF);
+		/* Save indication for new paths. */
+		cdev->private->path_new_mask = sch->vpm;
 		return;
 	}
 	/* Driver doesn't want device back. */
···
 	}
 }
 
+static void ccw_device_report_path_events(struct ccw_device *cdev)
+{
+	struct subchannel *sch = to_subchannel(cdev->dev.parent);
+	int path_event[8];
+	int chp, mask;
+
+	for (chp = 0, mask = 0x80; chp < 8; chp++, mask >>= 1) {
+		path_event[chp] = PE_NONE;
+		if (mask & cdev->private->path_gone_mask & ~(sch->vpm))
+			path_event[chp] |= PE_PATH_GONE;
+		if (mask & cdev->private->path_new_mask & sch->vpm)
+			path_event[chp] |= PE_PATH_AVAILABLE;
+		if (mask & cdev->private->pgid_reset_mask & sch->vpm)
+			path_event[chp] |= PE_PATHGROUP_ESTABLISHED;
+	}
+	if (cdev->online && cdev->drv->path_event)
+		cdev->drv->path_event(cdev, path_event);
+}
+
+static void ccw_device_reset_path_events(struct ccw_device *cdev)
+{
+	cdev->private->path_gone_mask = 0;
+	cdev->private->path_new_mask = 0;
+	cdev->private->pgid_reset_mask = 0;
+}
+
 void
 ccw_device_verify_done(struct ccw_device *cdev, int err)
 {
···
 					      &cdev->private->irb);
 			memset(&cdev->private->irb, 0, sizeof(struct irb));
 		}
+		ccw_device_report_path_events(cdev);
 		break;
 	case -ETIME:
 	case -EUSERS:
···
 		ccw_device_done(cdev, DEV_STATE_NOT_OPER);
 		break;
 	}
+	ccw_device_reset_path_events(cdev);
 }
 
 /*

drivers/s390/cio/device_pgid.c

···
 	spid_do(cdev);
 }
 
+static int pgid_is_reset(struct pgid *p)
+{
+	char *c;
+
+	for (c = (char *)p + 1; c < (char *)(p + 1); c++) {
+		if (*c != 0)
+			return 0;
+	}
+	return 1;
+}
+
 static int pgid_cmp(struct pgid *p1, struct pgid *p2)
 {
 	return memcmp((char *) p1 + 1, (char *) p2 + 1,
···
  * Determine pathgroup state from PGID data.
  */
 static void pgid_analyze(struct ccw_device *cdev, struct pgid **p,
-			 int *mismatch, int *reserved, int *reset)
+			 int *mismatch, int *reserved, u8 *reset)
 {
 	struct pgid *pgid = &cdev->private->pgid[0];
 	struct pgid *first = NULL;
···
 			continue;
 		if (pgid->inf.ps.state2 == SNID_STATE2_RESVD_ELSE)
 			*reserved = 1;
-		if (pgid->inf.ps.state1 == SNID_STATE1_RESET) {
-			/* A PGID was reset. */
-			*reset = 1;
+		if (pgid_is_reset(pgid)) {
+			*reset |= lpm;
 			continue;
 		}
 		if (!first) {
···
 	struct pgid *pgid;
 	int mismatch = 0;
 	int reserved = 0;
-	int reset = 0;
+	u8 reset = 0;
 	u8 donepm;
 
 	if (rc)
···
 		donepm = pgid_to_donepm(cdev);
 		sch->vpm = donepm & sch->opm;
 		cdev->private->pgid_todo_mask &= ~donepm;
+		cdev->private->pgid_reset_mask |= reset;
 		pgid_fill(cdev, pgid);
 	}
 out:
 	CIO_MSG_EVENT(2, "snid: device 0.%x.%04x: rc=%d pvm=%02x vpm=%02x "
-		      "todo=%02x mism=%d rsvd=%d reset=%d\n", id->ssid,
+		      "todo=%02x mism=%d rsvd=%d reset=%02x\n", id->ssid,
 		      id->devno, rc, cdev->private->pgid_valid_mask, sch->vpm,
 		      cdev->private->pgid_todo_mask, mismatch, reserved, reset);
 	switch (rc) {

drivers/s390/cio/io_sch.h

···
 	struct subchannel_id schid;	/* subchannel number */
 	struct ccw_request req;		/* internal I/O request */
 	int iretry;
-	u8 pgid_valid_mask;		/* mask of valid PGIDs */
-	u8 pgid_todo_mask;		/* mask of PGIDs to be adjusted */
+	u8 pgid_valid_mask;	/* mask of valid PGIDs */
+	u8 pgid_todo_mask;	/* mask of PGIDs to be adjusted */
+	u8 pgid_reset_mask;	/* mask of PGIDs which were reset */
+	u8 path_gone_mask;	/* mask of paths, that became unavailable */
+	u8 path_new_mask;	/* mask of paths, that became available */
 	struct {
 		unsigned int fast:1;	/* post with "channel end" */
 		unsigned int repall:1;	/* report every interrupt status */