From: Stephen M. Cameron <scame...@beardog.cce.hp.com>

* Do not check event bits on locked up controllers to
  see if they need to be rescanned.
* Do not initiate any device rescans on controllers
  which are known to be locked up.

Signed-off-by: Stephen M. Cameron <scame...@beardog.cce.hp.com>
---
 drivers/scsi/hpsa.c |   39 +++++++++++++++++++++++++++++++++++----
 1 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 1383169..f88bb73 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -2875,11 +2875,38 @@ static int hpsa_scsi_queue_command_lck(struct scsi_cmnd 
*cmd,
 
 static DEF_SCSI_QCMD(hpsa_scsi_queue_command)
 
+static int do_not_scan_if_controller_locked_up(struct ctlr_info *h)
+{
+       unsigned long flags;
+
+       /*
+        * Don't let rescans be initiated on a controller known
+        * to be locked up.  If the controller locks up *during*
+        * a rescan, that thread is probably hosed, but at least
+        * we can prevent new rescan threads from piling up on a
+        * locked up controller.
+        */
+       spin_lock_irqsave(&h->lock, flags);
+       if (unlikely(h->lockup_detected)) {
+               spin_unlock_irqrestore(&h->lock, flags);
+               spin_lock_irqsave(&h->scan_lock, flags);
+               h->scan_finished = 1;
+               wake_up_all(&h->scan_wait_queue);
+               spin_unlock_irqrestore(&h->scan_lock, flags);
+               return 1;
+       }
+       spin_unlock_irqrestore(&h->lock, flags);
+       return 0;
+}
+
 static void hpsa_scan_start(struct Scsi_Host *sh)
 {
        struct ctlr_info *h = shost_to_hba(sh);
        unsigned long flags;
 
+       if (do_not_scan_if_controller_locked_up(h))
+               return;
+
        /* wait until any scan already in progress is finished. */
        while (1) {
                spin_lock_irqsave(&h->scan_lock, flags);
@@ -2896,6 +2923,9 @@ static void hpsa_scan_start(struct Scsi_Host *sh)
        h->scan_finished = 0; /* mark scan as in progress */
        spin_unlock_irqrestore(&h->scan_lock, flags);
 
+       if (do_not_scan_if_controller_locked_up(h))
+               return;
+
        hpsa_update_scsi_devices(h, h->scsi_host->host_no);
 
        spin_lock_irqsave(&h->scan_lock, flags);
@@ -5389,7 +5419,7 @@ static void controller_lockup_detected(struct ctlr_info 
*h)
        spin_unlock_irqrestore(&h->lock, flags);
 }
 
-static void detect_controller_lockup(struct ctlr_info *h)
+static int detect_controller_lockup(struct ctlr_info *h)
 {
        u64 now;
        u32 heartbeat;
@@ -5399,7 +5429,7 @@ static void detect_controller_lockup(struct ctlr_info *h)
        /* If we've received an interrupt recently, we're ok. */
        if (time_after64(h->last_intr_timestamp +
                                (h->heartbeat_sample_interval), now))
-               return;
+               return 0;
 
        /*
         * If we've already checked the heartbeat recently, we're ok.
@@ -5408,7 +5438,7 @@ static void detect_controller_lockup(struct ctlr_info *h)
         */
        if (time_after64(h->last_heartbeat_timestamp +
                                (h->heartbeat_sample_interval), now))
-               return;
+               return 0;
 
        /* If heartbeat has not changed since we last looked, we're not ok. */
        spin_lock_irqsave(&h->lock, flags);
@@ -5416,12 +5446,13 @@ static void detect_controller_lockup(struct ctlr_info 
*h)
        spin_unlock_irqrestore(&h->lock, flags);
        if (h->last_heartbeat == heartbeat) {
                controller_lockup_detected(h);
-               return;
+               return 1;
        }
 
        /* We're ok. */
        h->last_heartbeat = heartbeat;
        h->last_heartbeat_timestamp = now;
+       return 0;
 }
 
 static int hpsa_kickoff_rescan(struct ctlr_info *h)

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