[PATCHv2 0/6] SCSI 'access_state' attribute

[PATCHv2 0/6] SCSI 'access_state' attribute

[Hannes Reinecke]

Hi all,

here's the patchset to add an 'access_state' and 'preferred_path'
attribute. It will display the access state of a path if a
hardware handler is attached.
The access_state is given in terms of SCSI ALUA, and
the vendor-specific access state (eg for rdac or alua)
are mapped onto the ALUA values.
Additionally the 'is_visible' callback is updated to
only display the attributes if they are supported.

Changes to v1:
- Use sprintf instead of snprintf
- Call missing scsi_dh_remove() after a failed device_add()

Hannes Reinecke (6):
  scsi: Add 'access_state' and 'preferred_path' attribute
  scsi_dh_alua: use common definitions for ALUA state
  scsi_dh_alua: update 'access_state' field
  scsi_dh_rdac: update 'access_state' field
  scsi_dh_emc: update 'access_state' field
  scsi_sysfs: call 'device_add' after attaching device handler

 drivers/scsi/device_handler/scsi_dh_alua.c | 106 +++++++++++++++++++----------
 drivers/scsi/device_handler/scsi_dh_emc.c  |   7 +-
 drivers/scsi/device_handler/scsi_dh_rdac.c |  38 +++++++++--
 drivers/scsi/scsi_sysfs.c                  |  89 ++++++++++++++++++++++--
 include/scsi/scsi_device.h                 |   1 +
 include/scsi/scsi_proto.h                  |  12 ++++
 6 files changed, 203 insertions(+), 50 deletions(-)

-- 
1.8.5.6

[PATCHv2 1/6] scsi: Add 'access_state' and 'preferred_path' attribute

[Hannes Reinecke]

Add an 'access_state' field to struct scsi_device
and display them in sysfs as 'access_state' and
'preferred_path' attribute.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/scsi_sysfs.c  | 74 ++++++++++++++++++++++++++++++++++++++++++++++
 include/scsi/scsi_device.h |  1 +
 include/scsi/scsi_proto.h  | 12 ++++++++
 3 files changed, 87 insertions(+)

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 7e57800..c5ac171 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -81,6 +81,33 @@ const char *scsi_host_state_name(enum scsi_host_state state)
 	return name;
 }
 
+static const struct {
+	unsigned char	value;
+	char		*name;
+} sdev_access_states[] = {
+	{ SCSI_ACCESS_STATE_OPTIMAL, "active/optimized" },
+	{ SCSI_ACCESS_STATE_ACTIVE, "active/non-optimized" },
+	{ SCSI_ACCESS_STATE_STANDBY, "standby" },
+	{ SCSI_ACCESS_STATE_UNAVAILABLE, "unavailable" },
+	{ SCSI_ACCESS_STATE_LBA, "lba-dependent" },
+	{ SCSI_ACCESS_STATE_OFFLINE, "offline" },
+	{ SCSI_ACCESS_STATE_TRANSITIONING, "transitioning" },
+};
+
+const char *scsi_access_state_name(unsigned char state)
+{
+	int i;
+	char *name = NULL;
+
+	for (i = 0; i < ARRAY_SIZE(sdev_access_states); i++) {
+		if (sdev_access_states[i].value == state) {
+			name = sdev_access_states[i].name;
+			break;
+		}
+	}
+	return name;
+}
+
 static int check_set(unsigned long long *val, char *src)
 {
 	char *last;
@@ -973,6 +1000,43 @@ sdev_store_dh_state(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR(dh_state, S_IRUGO | S_IWUSR, sdev_show_dh_state,
 		   sdev_store_dh_state);
+
+static ssize_t
+sdev_show_access_state(struct device *dev,
+		       struct device_attribute *attr,
+		       char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	unsigned char access_state;
+	const char *access_state_name;
+
+	if (!sdev->handler)
+		return -EINVAL;
+
+	access_state = (sdev->access_state & SCSI_ACCESS_STATE_MASK);
+	access_state_name = scsi_access_state_name(access_state);
+
+	return sprintf(buf, "%s\n",
+		       access_state_name ? access_state_name : "unknown");
+}
+static DEVICE_ATTR(access_state, S_IRUGO, sdev_show_access_state, NULL);
+
+static ssize_t
+sdev_show_preferred_path(struct device *dev,
+			 struct device_attribute *attr,
+			 char *buf)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+
+	if (!sdev->handler)
+		return -EINVAL;
+
+	if (sdev->access_state & SCSI_ACCESS_STATE_PREFERRED)
+		return sprintf(buf, "1\n");
+	else
+		return sprintf(buf, "0\n");
+}
+static DEVICE_ATTR(preferred_path, S_IRUGO, sdev_show_preferred_path, NULL);
 #endif
 
 static ssize_t
@@ -1020,6 +1084,14 @@ static umode_t scsi_sdev_attr_is_visible(struct kobject *kobj,
 	    !sdev->host->hostt->change_queue_depth)
 		return 0;
 
+#ifdef CONFIG_SCSI_DH
+	if (attr == &dev_attr_access_state.attr &&
+	    !sdev->handler)
+		return 0;
+	if (attr == &dev_attr_preferred_path.attr &&
+	    !sdev->handler)
+		return 0;
+#endif
 	return attr->mode;
 }
 
@@ -1063,6 +1135,8 @@ static struct attribute *scsi_sdev_attrs[] = {
 	&dev_attr_wwid.attr,
 #ifdef CONFIG_SCSI_DH
 	&dev_attr_dh_state.attr,
+	&dev_attr_access_state.attr,
+	&dev_attr_preferred_path.attr,
 #endif
 	&dev_attr_queue_ramp_up_period.attr,
 	REF_EVT(media_change),
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 4af2b24..c067019 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -201,6 +201,7 @@ struct scsi_device {
 	struct scsi_device_handler *handler;
 	void			*handler_data;
 
+	unsigned char		access_state;
 	enum scsi_device_state sdev_state;
 	unsigned long		sdev_data[0];
 } __attribute__((aligned(sizeof(unsigned long))));
diff --git a/include/scsi/scsi_proto.h b/include/scsi/scsi_proto.h
index a9fbf1b..c2ae21c 100644
--- a/include/scsi/scsi_proto.h
+++ b/include/scsi/scsi_proto.h
@@ -277,5 +277,17 @@ struct scsi_lun {
 	__u8 scsi_lun[8];
 };
 
+/* SPC asymmetric access states */
+#define SCSI_ACCESS_STATE_OPTIMAL     0x00
+#define SCSI_ACCESS_STATE_ACTIVE      0x01
+#define SCSI_ACCESS_STATE_STANDBY     0x02
+#define SCSI_ACCESS_STATE_UNAVAILABLE 0x03
+#define SCSI_ACCESS_STATE_LBA         0x04
+#define SCSI_ACCESS_STATE_OFFLINE     0x0e
+#define SCSI_ACCESS_STATE_TRANSITIONING 0x0f
+
+/* Values for REPORT TARGET GROUP STATES */
+#define SCSI_ACCESS_STATE_MASK        0x0f
+#define SCSI_ACCESS_STATE_PREFERRED   0x80
 
 #endif /* _SCSI_PROTO_H_ */
-- 
1.8.5.6

[PATCHv2 2/6] scsi_dh_alua: use common definitions for ALUA state

[Hannes Reinecke]

scsi_proto.h now contains definitions for the ALUA state,
so we don't have to carry them in the device handler.

Reviewed-by: Bart van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 58 +++++++++++++-----------------
 1 file changed, 25 insertions(+), 33 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 9a7657e..19f6539 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -31,14 +31,6 @@
 #define ALUA_DH_NAME "alua"
 #define ALUA_DH_VER "2.0"
 
-#define TPGS_STATE_OPTIMIZED		0x0
-#define TPGS_STATE_NONOPTIMIZED		0x1
-#define TPGS_STATE_STANDBY		0x2
-#define TPGS_STATE_UNAVAILABLE		0x3
-#define TPGS_STATE_LBA_DEPENDENT	0x4
-#define TPGS_STATE_OFFLINE		0xe
-#define TPGS_STATE_TRANSITIONING	0xf
-
 #define TPGS_SUPPORT_NONE		0x00
 #define TPGS_SUPPORT_OPTIMIZED		0x01
 #define TPGS_SUPPORT_NONOPTIMIZED	0x02
@@ -180,7 +172,7 @@ static int submit_stpg(struct scsi_device *sdev, int group_id,
 
 	/* Prepare the data buffer */
 	memset(stpg_data, 0, stpg_len);
-	stpg_data[4] = TPGS_STATE_OPTIMIZED & 0x0f;
+	stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL;
 	put_unaligned_be16(group_id, &stpg_data[6]);
 
 	/* Prepare the command. */
@@ -248,7 +240,7 @@ struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
 	}
 	pg->group_id = group_id;
 	pg->tpgs = tpgs;
-	pg->state = TPGS_STATE_OPTIMIZED;
+	pg->state = SCSI_ACCESS_STATE_OPTIMAL;
 	if (optimize_stpg)
 		pg->flags |= ALUA_OPTIMIZE_STPG;
 	kref_init(&pg->kref);
@@ -378,22 +370,22 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
 	return SCSI_DH_OK;
 }
 
-static char print_alua_state(int state)
+static char print_alua_state(unsigned char state)
 {
 	switch (state) {
-	case TPGS_STATE_OPTIMIZED:
+	case SCSI_ACCESS_STATE_OPTIMAL:
 		return 'A';
-	case TPGS_STATE_NONOPTIMIZED:
+	case SCSI_ACCESS_STATE_ACTIVE:
 		return 'N';
-	case TPGS_STATE_STANDBY:
+	case SCSI_ACCESS_STATE_STANDBY:
 		return 'S';
-	case TPGS_STATE_UNAVAILABLE:
+	case SCSI_ACCESS_STATE_UNAVAILABLE:
 		return 'U';
-	case TPGS_STATE_LBA_DEPENDENT:
+	case SCSI_ACCESS_STATE_LBA:
 		return 'L';
-	case TPGS_STATE_OFFLINE:
+	case SCSI_ACCESS_STATE_OFFLINE:
 		return 'O';
-	case TPGS_STATE_TRANSITIONING:
+	case SCSI_ACCESS_STATE_TRANSITIONING:
 		return 'T';
 	default:
 		return 'X';
@@ -647,7 +639,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		    valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
 
 	switch (pg->state) {
-	case TPGS_STATE_TRANSITIONING:
+	case SCSI_ACCESS_STATE_TRANSITIONING:
 		if (time_before(jiffies, pg->expiry)) {
 			/* State transition, retry */
 			pg->interval = 2;
@@ -655,11 +647,11 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		} else {
 			/* Transitioning time exceeded, set port to standby */
 			err = SCSI_DH_IO;
-			pg->state = TPGS_STATE_STANDBY;
+			pg->state = SCSI_ACCESS_STATE_STANDBY;
 			pg->expiry = 0;
 		}
 		break;
-	case TPGS_STATE_OFFLINE:
+	case SCSI_ACCESS_STATE_OFFLINE:
 		/* Path unusable */
 		err = SCSI_DH_DEV_OFFLINED;
 		pg->expiry = 0;
@@ -693,20 +685,20 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
 		return SCSI_DH_RETRY;
 	}
 	switch (pg->state) {
-	case TPGS_STATE_OPTIMIZED:
+	case SCSI_ACCESS_STATE_OPTIMAL:
 		return SCSI_DH_OK;
-	case TPGS_STATE_NONOPTIMIZED:
+	case SCSI_ACCESS_STATE_ACTIVE:
 		if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
 		    !pg->pref &&
 		    (pg->tpgs & TPGS_MODE_IMPLICIT))
 			return SCSI_DH_OK;
 		break;
-	case TPGS_STATE_STANDBY:
-	case TPGS_STATE_UNAVAILABLE:
+	case SCSI_ACCESS_STATE_STANDBY:
+	case SCSI_ACCESS_STATE_UNAVAILABLE:
 		break;
-	case TPGS_STATE_OFFLINE:
+	case SCSI_ACCESS_STATE_OFFLINE:
 		return SCSI_DH_IO;
-	case TPGS_STATE_TRANSITIONING:
+	case SCSI_ACCESS_STATE_TRANSITIONING:
 		break;
 	default:
 		sdev_printk(KERN_INFO, sdev,
@@ -760,7 +752,7 @@ static void alua_rtpg_work(struct work_struct *work)
 
 		pg->flags &= ~ALUA_PG_RUN_RTPG;
 		spin_unlock_irqrestore(&pg->lock, flags);
-		if (state == TPGS_STATE_TRANSITIONING) {
+		if (state == SCSI_ACCESS_STATE_TRANSITIONING) {
 			if (alua_tur(sdev) == SCSI_DH_RETRY) {
 				spin_lock_irqsave(&pg->lock, flags);
 				pg->flags &= ~ALUA_PG_RUNNING;
@@ -1006,7 +998,7 @@ static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
 {
 	struct alua_dh_data *h = sdev->handler_data;
 	struct alua_port_group __rcu *pg;
-	int state = TPGS_STATE_OPTIMIZED;
+	unsigned char state = SCSI_ACCESS_STATE_OPTIMAL;
 	int ret = BLKPREP_OK;
 
 	rcu_read_lock();
@@ -1014,11 +1006,11 @@ static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
 	if (pg)
 		state = pg->state;
 	rcu_read_unlock();
-	if (state == TPGS_STATE_TRANSITIONING)
+	if (state == SCSI_ACCESS_STATE_TRANSITIONING)
 		ret = BLKPREP_DEFER;
-	else if (state != TPGS_STATE_OPTIMIZED &&
-		 state != TPGS_STATE_NONOPTIMIZED &&
-		 state != TPGS_STATE_LBA_DEPENDENT) {
+	else if (state != SCSI_ACCESS_STATE_OPTIMAL &&
+		 state != SCSI_ACCESS_STATE_ACTIVE &&
+		 state != SCSI_ACCESS_STATE_LBA) {
 		ret = BLKPREP_KILL;
 		req->cmd_flags |= REQ_QUIET;
 	}
-- 
1.8.5.6

[PATCHv2 3/6] scsi_dh_alua: update 'access_state' field

[Hannes Reinecke]

Track attached SCSI devices and update the 'access_state' field
whenever an ALUA state change has been detected.

Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 48 ++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 19f6539..5bcdf8d 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <asm/unaligned.h>
 #include <scsi/scsi.h>
+#include <scsi/scsi_proto.h>
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_eh.h>
 #include <scsi/scsi_dh.h>
@@ -75,6 +76,7 @@ struct alua_port_group {
 	struct kref		kref;
 	struct rcu_head		rcu;
 	struct list_head	node;
+	struct list_head	dh_list;
 	unsigned char		device_id_str[256];
 	int			device_id_len;
 	int			group_id;
@@ -92,6 +94,7 @@ struct alua_port_group {
 };
 
 struct alua_dh_data {
+	struct list_head	node;
 	struct alua_port_group	*pg;
 	int			group_id;
 	spinlock_t		pg_lock;
@@ -247,6 +250,7 @@ struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
 	INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
 	INIT_LIST_HEAD(&pg->rtpg_list);
 	INIT_LIST_HEAD(&pg->node);
+	INIT_LIST_HEAD(&pg->dh_list);
 	spin_lock_init(&pg->lock);
 
 	spin_lock(&port_group_lock);
@@ -328,6 +332,8 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
 {
 	int rel_port = -1, group_id;
 	struct alua_port_group *pg, *old_pg = NULL;
+	bool pg_updated;
+	unsigned long flags;
 
 	group_id = scsi_vpd_tpg_id(sdev, &rel_port);
 	if (group_id < 0) {
@@ -357,10 +363,22 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
 	old_pg = h->pg;
 	if (old_pg != pg) {
 		/* port group has changed. Update to new port group */
+		if (h->pg) {
+			spin_lock_irqsave(&old_pg->lock, flags);
+			list_del_rcu(&h->node);
+			spin_unlock_irqrestore(&old_pg->lock, flags);
+		}
 		rcu_assign_pointer(h->pg, pg);
+		pg_updated = true;
 	}
+
+	spin_lock_irqsave(&pg->lock, flags);
 	if (sdev->synchronous_alua)
 		pg->flags |= ALUA_SYNC_STPG;
+	if (pg_updated)
+		list_add_rcu(&h->node, &pg->dh_list);
+	spin_unlock_irqrestore(&pg->lock, flags);
+
 	alua_rtpg_queue(h->pg, sdev, NULL, true);
 	spin_unlock(&h->pg_lock);
 
@@ -613,8 +631,18 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 			if (spin_trylock_irqsave(&tmp_pg->lock, flags)) {
 				if ((tmp_pg == pg) ||
 				    !(tmp_pg->flags & ALUA_PG_RUNNING)) {
+					struct alua_dh_data *h;
+
 					tmp_pg->state = desc[0] & 0x0f;
 					tmp_pg->pref = desc[0] >> 7;
+					rcu_read_lock();
+					list_for_each_entry_rcu(h,
+						&tmp_pg->dh_list, node) {
+						/* h->sdev should always be valid */
+						BUG_ON(!h->sdev);
+						h->sdev->access_state = desc[0];
+					}
+					rcu_read_unlock();
 				}
 				if (tmp_pg == pg)
 					valid_states = desc[1];
@@ -645,10 +673,22 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
 			pg->interval = 2;
 			err = SCSI_DH_RETRY;
 		} else {
+			struct alua_dh_data *h;
+
 			/* Transitioning time exceeded, set port to standby */
 			err = SCSI_DH_IO;
 			pg->state = SCSI_ACCESS_STATE_STANDBY;
 			pg->expiry = 0;
+			rcu_read_lock();
+			list_for_each_entry_rcu(h, &pg->dh_list, node) {
+				BUG_ON(!h->sdev);
+				h->sdev->access_state =
+					(pg->state & SCSI_ACCESS_STATE_MASK);
+				if (pg->pref)
+					h->sdev->access_state |=
+						SCSI_ACCESS_STATE_PREFERRED;
+			}
+			rcu_read_unlock();
 		}
 		break;
 	case SCSI_ACCESS_STATE_OFFLINE:
@@ -1041,6 +1081,7 @@ static int alua_bus_attach(struct scsi_device *sdev)
 	rcu_assign_pointer(h->pg, NULL);
 	h->init_error = SCSI_DH_OK;
 	h->sdev = sdev;
+	INIT_LIST_HEAD(&h->node);
 
 	mutex_init(&h->init_mutex);
 	err = alua_initialize(sdev, h);
@@ -1070,9 +1111,12 @@ static void alua_bus_detach(struct scsi_device *sdev)
 	rcu_assign_pointer(h->pg, NULL);
 	h->sdev = NULL;
 	spin_unlock(&h->pg_lock);
-	if (pg)
+	if (pg) {
+		spin_lock(&pg->lock);
+		list_del_rcu(&h->node);
+		spin_unlock(&pg->lock);
 		kref_put(&pg->kref, release_port_group);
-
+	}
 	sdev->handler_data = NULL;
 	kfree(h);
 }
-- 
1.8.5.6

[PATCHv2 4/6] scsi_dh_rdac: update 'access_state' field

[Hannes Reinecke]

Track attached SCSI devices and update the 'access_state'
whenever the path state of the device changes.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/device_handler/scsi_dh_rdac.c | 38 ++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index 93880ed..06fbd0b 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -165,6 +165,7 @@ struct rdac_controller {
 	struct work_struct	ms_work;
 	struct scsi_device	*ms_sdev;
 	struct list_head	ms_head;
+	struct list_head	dh_list;
 };
 
 struct c2_inquiry {
@@ -181,7 +182,9 @@ struct c2_inquiry {
 };
 
 struct rdac_dh_data {
+	struct list_head	node;
 	struct rdac_controller	*ctlr;
+	struct scsi_device	*sdev;
 #define UNINITIALIZED_LUN	(1 << 8)
 	unsigned		lun;
 
@@ -392,6 +395,7 @@ static struct rdac_controller *get_controller(int index, char *array_name,
 	INIT_WORK(&ctlr->ms_work, send_mode_select);
 	INIT_LIST_HEAD(&ctlr->ms_head);
 	list_add(&ctlr->node, &ctlr_list);
+	INIT_LIST_HEAD(&ctlr->dh_list);
 
 	return ctlr;
 }
@@ -455,7 +459,8 @@ static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
 
 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
 {
-	int err;
+	int err, access_state;
+	struct rdac_dh_data *tmp;
 	struct c9_inquiry *inqp;
 
 	h->state = RDAC_STATE_ACTIVE;
@@ -471,19 +476,31 @@ static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
 			h->mode = RDAC_MODE; /* LUN in RDAC mode */
 
 		/* Update ownership */
-		if (inqp->avte_cvp & 0x1)
+		if (inqp->avte_cvp & 0x1) {
 			h->lun_state = RDAC_LUN_OWNED;
-		else {
+			access_state = SCSI_ACCESS_STATE_OPTIMAL;
+		} else {
 			h->lun_state = RDAC_LUN_UNOWNED;
-			if (h->mode == RDAC_MODE)
+			if (h->mode == RDAC_MODE) {
 				h->state = RDAC_STATE_PASSIVE;
+				access_state = SCSI_ACCESS_STATE_STANDBY;
+			} else
+				access_state = SCSI_ACCESS_STATE_ACTIVE;
 		}
 
 		/* Update path prio*/
-		if (inqp->path_prio & 0x1)
+		if (inqp->path_prio & 0x1) {
 			h->preferred = RDAC_PREFERRED;
-		else
+			access_state |= SCSI_ACCESS_STATE_PREFERRED;
+		} else
 			h->preferred = RDAC_NON_PREFERRED;
+		rcu_read_lock();
+		list_for_each_entry_rcu(tmp, &h->ctlr->dh_list, node) {
+			/* h->sdev should always be valid */
+			BUG_ON(!tmp->sdev);
+			tmp->sdev->access_state = access_state;
+		}
+		rcu_read_unlock();
 	}
 
 	return err;
@@ -508,6 +525,10 @@ static int initialize_controller(struct scsi_device *sdev,
 		h->ctlr = get_controller(index, array_name, array_id, sdev);
 		if (!h->ctlr)
 			err = SCSI_DH_RES_TEMP_UNAVAIL;
+		else {
+			list_add_rcu(&h->node, &h->ctlr->dh_list);
+			h->sdev = sdev;
+		}
 		spin_unlock(&list_lock);
 	}
 	return err;
@@ -829,8 +850,11 @@ static void rdac_bus_detach( struct scsi_device *sdev )
 		flush_workqueue(kmpath_rdacd);
 
 	spin_lock(&list_lock);
-	if (h->ctlr)
+	if (h->ctlr) {
+		list_del_rcu(&h->node);
+		h->sdev = NULL;
 		kref_put(&h->ctlr->kref, release_controller);
+	}
 	spin_unlock(&list_lock);
 	sdev->handler_data = NULL;
 	kfree(h);
-- 
1.8.5.6

[PATCHv2 5/6] scsi_dh_emc: update 'access_state' field

[Hannes Reinecke]

Update the 'access_state' field of the SCSI device whenever
the path state changes.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/device_handler/scsi_dh_emc.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
index e6fb97c..375d818 100644
--- a/drivers/scsi/device_handler/scsi_dh_emc.c
+++ b/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -199,7 +199,12 @@ static int parse_sp_info_reply(struct scsi_device *sdev,
 	csdev->lun_state = csdev->buffer[4];
 	csdev->current_sp = csdev->buffer[8];
 	csdev->port = csdev->buffer[7];
-
+	if (csdev->lun_state == CLARIION_LUN_OWNED)
+		sdev->access_state = SCSI_ACCESS_STATE_OPTIMAL;
+	else
+		sdev->access_state = SCSI_ACCESS_STATE_STANDBY;
+	if (csdev->default_sp == csdev->current_sp)
+		sdev->access_state |= SCSI_ACCESS_STATE_PREFERRED;
 out:
 	return err;
 }
-- 
1.8.5.6

[PATCHv2 6/6] scsi_sysfs: call 'device_add' after attaching device handler

[Hannes Reinecke]

'device_add' will be evaluating the 'is_visible' callback
when creating the sysfs attributes. As by this time the
device handler has not been attached the 'access_state'
attribute will never be visible.

This patch moves the code around so that the device handler
is present by the time 'is_visible' is evaluated to
correctly display the 'access_state' attribute.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/scsi_sysfs.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index c5ac171..d164419 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1220,13 +1220,6 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 
 	scsi_autopm_get_device(sdev);
 
-	error = device_add(&sdev->sdev_gendev);
-	if (error) {
-		sdev_printk(KERN_INFO, sdev,
-				"failed to add device: %d\n", error);
-		return error;
-	}
-
 	error = scsi_dh_add_device(sdev);
 	if (error)
 		/*
@@ -1235,6 +1228,14 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 		sdev_printk(KERN_INFO, sdev,
 				"failed to add device handler: %d\n", error);
 
+	error = device_add(&sdev->sdev_gendev);
+	if (error) {
+		sdev_printk(KERN_INFO, sdev,
+				"failed to add device: %d\n", error);
+		scsi_dh_remove_device(sdev);
+		return error;
+	}
+
 	device_enable_async_suspend(&sdev->sdev_dev);
 	error = device_add(&sdev->sdev_dev);
 	if (error) {
-- 
1.8.5.6

Re: [PATCHv2 1/6] scsi: Add 'access_state' and 'preferred_path' attribute

[Johannes Thumshirn]

On Thu, Mar 03, 2016 at 07:54:07AM +0100, Hannes Reinecke wrote:
> Add an 'access_state' field to struct scsi_device
> and display them in sysfs as 'access_state' and
> 'preferred_path' attribute.
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Hannes Reinecke <hare@suse.de>

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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Re: [PATCHv2 2/6] scsi_dh_alua: use common definitions for ALUA state

[Johannes Thumshirn]

On Thu, Mar 03, 2016 at 07:54:08AM +0100, Hannes Reinecke wrote:
> scsi_proto.h now contains definitions for the ALUA state,
> so we don't have to carry them in the device handler.
> 
> Reviewed-by: Bart van Assche <bart.vanassche@sandisk.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Hannes Reinecke <hare@suse.de>

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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Re: [PATCHv2 3/6] scsi_dh_alua: update 'access_state' field

[Johannes Thumshirn]

On Thu, Mar 03, 2016 at 07:54:09AM +0100, Hannes Reinecke wrote:
> Track attached SCSI devices and update the 'access_state' field
> whenever an ALUA state change has been detected.
> 
> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
> Reviewed-by: Ewan Milne <emilne@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Hannes Reinecke <hare@suse.de>

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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Re: [PATCHv2 4/6] scsi_dh_rdac: update 'access_state' field

[Johannes Thumshirn]

On Thu, Mar 03, 2016 at 07:54:10AM +0100, Hannes Reinecke wrote:
> Track attached SCSI devices and update the 'access_state'
> whenever the path state of the device changes.
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Hannes Reinecke <hare@suse.com>

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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Re: [PATCHv2 5/6] scsi_dh_emc: update 'access_state' field

[Johannes Thumshirn]

On Thu, Mar 03, 2016 at 07:54:11AM +0100, Hannes Reinecke wrote:
> Update the 'access_state' field of the SCSI device whenever
> the path state changes.
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Hannes Reinecke <hare@suse.de>

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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Re: [PATCHv2 6/6] scsi_sysfs: call 'device_add' after attaching device handler

[Johannes Thumshirn]

On Thu, Mar 03, 2016 at 07:54:12AM +0100, Hannes Reinecke wrote:
> 'device_add' will be evaluating the 'is_visible' callback
> when creating the sysfs attributes. As by this time the
> device handler has not been attached the 'access_state'
> attribute will never be visible.
> 
> This patch moves the code around so that the device handler
> is present by the time 'is_visible' is evaluated to
> correctly display the 'access_state' attribute.
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Hannes Reinecke <hare@suse.de>

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
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Re: [PATCHv2 1/6] scsi: Add 'access_state' and 'preferred_path' attribute

[Bart Van Assche]

On 03/02/2016 10:54 PM, Hannes Reinecke wrote:
> Add an 'access_state' field to struct scsi_device
> and display them in sysfs as 'access_state' and
> 'preferred_path' attribute.

Reviewed-by: Bart van Assche <bart.vanassche@sandisk.com>

Re: [PATCHv2 6/6] scsi_sysfs: call 'device_add' after attaching device handler

[Bart Van Assche]

On 03/02/2016 10:54 PM, Hannes Reinecke wrote:
> 'device_add' will be evaluating the 'is_visible' callback
> when creating the sysfs attributes. As by this time the
> device handler has not been attached the 'access_state'
> attribute will never be visible.
>
> This patch moves the code around so that the device handler
> is present by the time 'is_visible' is evaluated to
> correctly display the 'access_state' attribute.

Reviewed-by: Bart van Assche <bart.vanassche@sandisk.com>

Re: [PATCHv2 0/6] SCSI 'access_state' attribute

[Martin K. Petersen]

>>>>> "Hannes" == Hannes Reinecke <hare@suse.de> writes:

Hannes> Hi all, here's the patchset to add an 'access_state' and
Hannes> 'preferred_path' attribute. It will display the access state of
Hannes> a path if a hardware handler is attached.  The access_state is
Hannes> given in terms of SCSI ALUA, and the vendor-specific access
Hannes> state (eg for rdac or alua) are mapped onto the ALUA values.
Hannes> Additionally the 'is_visible' callback is updated to only
Hannes> display the attributes if they are supported.

Applied to 4.6/scsi-queue.

-- 
Martin K. Petersen	Oracle Linux Engineering