massage the preferred path detection to happen when mpath asks for

a paths status, rather than on attach. the status it returns depends
on the type of device you have. hds provides two types of arrays,
symmetric and asymmetric.

on a symmetric device you can shove io down any path to any port
on any controller and it will work. on symmetric devices we say all
paths are part of the same group, and unconditionally return active
path status to any check request.

on asymmetric devices we group paths by which controller in teh
array they connect to. the controllers return whether theyre providing
a preferred path via a couple of status bits in a hds specific vpd
page, so we query that and return the state of the bits.

unfortunately hds arrays dont report change of lun ownership in any
way, so we dont currently have any way of failing over at the moment.
ill have to think about the least worst way to handle that.

tested by deraadt@ on hppa

1 files changed, 60 insertions, 46 deletions

diff --git a/sys/scsi/mpath_hds.c b/sys/scsi/mpath_hds.c
index 9348b49a65d..b2a593ba409 100644
--- a/sys/scsi/mpath_hds.c
+++ b/sys/scsi/mpath_hds.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mpath_hds.c,v 1.14 2013/12/06 21:03:02 deraadt Exp $ */
+/*	$OpenBSD: mpath_hds.c,v 1.15 2014/04/03 04:02:50 dlg Exp $ */
 
 /*
  * Copyright (c) 2011 David Gwynne <dlg@openbsd.org>
@@ -47,7 +47,7 @@
 #define HDS_VPD			0xe0
 
 struct hds_vpd {
-        struct scsi_vpd_hdr	hdr; /* HDS_VPD */
+	struct scsi_vpd_hdr	hdr; /* HDS_VPD */
 	u_int8_t		state;
 #define HDS_VPD_VALID			0x80
 #define HDS_VPD_PREFERRED		0x40
@@ -61,7 +61,10 @@ struct hds_vpd {
 struct hds_softc {
 	struct device		sc_dev;
 	struct mpath_path	sc_path;
+	struct scsi_xshandler	sc_xsh;
+	struct hds_vpd		*sc_vpd;
 	int			sc_mode;
+	int			sc_ctrl;
 };
 #define DEVNAME(_s) ((_s)->sc_dev.dv_xname)
 
@@ -101,7 +104,9 @@ struct hds_device {
 
 int		hds_inquiry(struct scsi_link *, int *);
 int		hds_info(struct hds_softc *);
-int		hds_preferred(struct hds_softc *, int *);
+
+void		hds_status(struct scsi_xfer *);
+void		hds_status_done(struct scsi_xfer *);
 
 struct hds_device hds_devices[] = {
 /*	  " vendor "  "     device     " */
@@ -140,7 +145,6 @@ hds_attach(struct device *parent, struct device *self, void *aux)
 	struct hds_softc *sc = (struct hds_softc *)self;
 	struct scsi_attach_args *sa = aux;
 	struct scsi_link *link = sa->sa_sc_link;
-	int preferred = 1;
 
 	printf("\n");
 
@@ -151,6 +155,10 @@ hds_attach(struct device *parent, struct device *self, void *aux)
 	scsi_xsh_set(&sc->sc_path.p_xsh, link, hds_mpath_start);
 	sc->sc_path.p_link = link;
 
+	/* init status handler */
+	scsi_xsh_set(&sc->sc_xsh, link, hds_status);
+	sc->sc_vpd = dma_alloc(sizeof(*sc->sc_vpd), PR_WAITOK);
+
 	if (hds_inquiry(link, &sc->sc_mode) != 0) {
 		printf("%s: unable to query controller mode\n", DEVNAME(sc));
 		return;
@@ -161,22 +169,19 @@ hds_attach(struct device *parent, struct device *self, void *aux)
 		return;
 	}
 
-	if (hds_preferred(sc, &preferred) != 0) {
-		printf("%s: unable to query preferred path\n", DEVNAME(sc));
-		return;
-	}
-
-	if (!preferred)
-		return;
-
-	/* XXX id isnt real, needs to come from hds_info */
-	if (mpath_path_attach(&sc->sc_path, 0, &hds_mpath_ops) != 0)
+	if (mpath_path_attach(&sc->sc_path,
+	    (sc->sc_mode == HDS_SYMMETRIC) ? 0 : sc->sc_ctrl,
+	    &hds_mpath_ops) != 0)
 		printf("%s: unable to attach path\n", DEVNAME(sc));
 }
 
 int
 hds_detach(struct device *self, int flags)
 {
+	struct hds_softc *sc = (struct hds_softc *)self;
+
+	dma_free(sc->sc_vpd, sizeof(*sc->sc_vpd));
+
 	return (0);
 }
 
@@ -214,7 +219,45 @@ hds_mpath_status(struct scsi_link *link)
 {
 	struct hds_softc *sc = link->device_softc;
 
-	mpath_path_status(&sc->sc_path, MPATH_S_UNKNOWN);
+	if (sc->sc_mode == HDS_SYMMETRIC)
+		mpath_path_status(&sc->sc_path, MPATH_S_ACTIVE);
+	else
+		scsi_xsh_add(&sc->sc_xsh);
+}
+
+void
+hds_status(struct scsi_xfer *xs)
+{
+	struct scsi_link *link = xs->sc_link;
+	struct hds_softc *sc = link->device_softc;
+
+	scsi_init_inquiry(xs, SI_EVPD, HDS_VPD,
+	    sc->sc_vpd, sizeof(*sc->sc_vpd));
+
+	xs->done = hds_status_done;
+
+	scsi_xs_exec(xs);
+}
+
+void
+hds_status_done(struct scsi_xfer *xs)
+{
+	struct scsi_link *link = xs->sc_link;
+	struct hds_softc *sc = link->device_softc;
+	struct hds_vpd *vpd = sc->sc_vpd;
+	int status;
+
+	scsi_xs_put(xs);
+
+	if (_2btol(vpd->hdr.page_length) < sizeof(vpd->state) ||
+	    !ISSET(vpd->state, HDS_VPD_VALID))
+		status = MPATH_S_UNKNOWN;
+	else if (ISSET(vpd->state, HDS_VPD_PREFERRED))
+		status = MPATH_S_ACTIVE;
+	else
+		status = MPATH_S_PASSIVE;
+
+	mpath_path_status(&sc->sc_path, status);
 }
 
 int
@@ -281,6 +324,8 @@ hds_info(struct hds_softc *sc)
 		printf("%s: ldev %s, controller %c, port %c, %s\n",
 		    DEVNAME(sc), ldev, ctrl, port,
 		    sc->sc_mode == HDS_SYMMETRIC ? "symmetric" : "asymmetric");
+
+		sc->sc_ctrl = ctrl;
 	} else
 		error = ENXIO;
 
@@ -288,34 +333,3 @@ done:
 	dma_free(buf, len);
 	return (error);
 }
-
-int
-hds_preferred(struct hds_softc *sc, int *preferred)
-{
-	struct scsi_link *link = sc->sc_path.p_link;
-	struct hds_vpd *pg;
-	int error;
-
-	if (sc->sc_mode == HDS_SYMMETRIC) {
-		*preferred = 1;
-		return (0);
-	}
-
-	pg = dma_alloc(sizeof(*pg), PR_WAITOK);
-
-	error = scsi_inquire_vpd(link, pg, sizeof(*pg), HDS_VPD, scsi_autoconf);
-	if (error)
-		goto done;
-
-	if (_2btol(pg->hdr.page_length) < sizeof(pg->state) ||
-	     !ISSET(pg->state, HDS_VPD_VALID)) {
-		error = ENXIO;
-		goto done;
-	}
-
-	*preferred = ISSET(pg->state, HDS_VPD_PREFERRED);
-
-done:
-	dma_free(pg, sizeof(*pg));
-	return (error);
-}