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 
> Signed-off-by: Hannes Reinecke 

Reviewed-by: Johannes Thumshirn 

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Johannes Thumshirn  Storage
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[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 
Signed-off-by: Hannes Reinecke 
---
 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_headms_head;
+   struct list_headdh_list;
 };
 
 struct c2_inquiry {
@@ -181,7 +182,9 @@ struct c2_inquiry {
 };
 
 struct rdac_dh_data {
+   struct list_headnode;
struct rdac_controller  *ctlr;
+   struct scsi_device  *sdev;
 #define UNINITIALIZED_LUN  (1 << 8)
unsignedlun;
 
@@ -392,6 +395,7 @@ static struct rdac_controller *get_controller(int index, 
char *array_name,
INIT_WORK(>ms_work, send_mode_select);
INIT_LIST_HEAD(>ms_head);
list_add(>node, _list);
+   INIT_LIST_HEAD(>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, >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(>node, >ctlr->dh_list);
+   h->sdev = sdev;
+   }
spin_unlock(_lock);
}
return err;
@@ -829,8 +850,11 @@ static void rdac_bus_detach( struct scsi_device *sdev )
flush_workqueue(kmpath_rdacd);
 
spin_lock(_lock);
-   if (h->ctlr)
+   if (h->ctlr) {
+   list_del_rcu(>node);
+   h->sdev = NULL;
kref_put(>ctlr->kref, release_controller);
+   }
spin_unlock(_lock);
sdev->handler_data = NULL;
kfree(h);
-- 
1.8.5.6

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