[PATCH 5/5] staging: hv: Gracefully handle SCSI resets - RESEND

[Hank Janssen]

(Send from a linux machine, not routed through exchange)

If we get a SCSI host bus reset we now gracefully handle it, and we 
take the device offline. This before sometimes caused hangs.

Signed-off-by:Hank Janssen <hjans...@microsoft.com
Signed-off-by:Haiyang Zhang <haiya...@microsoft.com


---
 drivers/staging/hv/storvsc.c |   36 +++++++++++++++++++++++++++++++++++-
 1 files changed, 35 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/hv/storvsc.c b/drivers/staging/hv/storvsc.c
index 6bd2ff1..5f222cf 100644
--- a/drivers/staging/hv/storvsc.c
+++ b/drivers/staging/hv/storvsc.c
@@ -48,7 +48,9 @@ struct storvsc_device {
 
        /* 0 indicates the device is being destroyed */
        atomic_t RefCount;
-
+       
+       int reset;
+       spinlock_t lock;
        atomic_t NumOutstandingRequests;
 
        /*
@@ -93,6 +95,9 @@ static inline struct storvsc_device *AllocStorDevice(struct 
hv_device *Device)
        atomic_cmpxchg(&storDevice->RefCount, 0, 2);
 
        storDevice->Device = Device;
+       storDevice->reset  = 0;
+       spin_lock_init(&storDevice->lock);
+
        Device->Extension = storDevice;
 
        return storDevice;
@@ -101,6 +106,7 @@ static inline struct storvsc_device *AllocStorDevice(struct 
hv_device *Device)
 static inline void FreeStorDevice(struct storvsc_device *Device)
 {
        /* ASSERT(atomic_read(&Device->RefCount) == 0); */
+       /*kfree(Device->lock);*/
        kfree(Device);
 }
 
@@ -108,13 +114,24 @@ static inline void FreeStorDevice(struct storvsc_device 
*Device)
 static inline struct storvsc_device *GetStorDevice(struct hv_device *Device)
 {
        struct storvsc_device *storDevice;
+       unsigned long flags;
 
        storDevice = (struct storvsc_device *)Device->Extension;
+
+       spin_lock_irqsave(&storDevice->lock, flags);
+
+       if (storDevice->reset == 1) {
+               spin_unlock_irqrestore(&storDevice->lock, flags);
+               return NULL;
+       }
+
        if (storDevice && atomic_read(&storDevice->RefCount) > 1)
                atomic_inc(&storDevice->RefCount);
        else
                storDevice = NULL;
 
+       spin_unlock_irqrestore(&storDevice->lock, flags);
+
        return storDevice;
 }
 
@@ -122,13 +139,19 @@ static inline struct storvsc_device *GetStorDevice(struct 
hv_device *Device)
 static inline struct storvsc_device *MustGetStorDevice(struct hv_device 
*Device)
 {
        struct storvsc_device *storDevice;
+       unsigned long flags;
 
        storDevice = (struct storvsc_device *)Device->Extension;
+
+       spin_lock_irqsave(&storDevice->lock, flags);
+
        if (storDevice && atomic_read(&storDevice->RefCount))
                atomic_inc(&storDevice->RefCount);
        else
                storDevice = NULL;
 
+       spin_unlock_irqrestore(&storDevice->lock, flags);
+
        return storDevice;
 }
 
@@ -614,6 +637,7 @@ int StorVscOnHostReset(struct hv_device *Device)
        struct storvsc_device *storDevice;
        struct storvsc_request_extension *request;
        struct vstor_packet *vstorPacket;
+       unsigned long flags;
        int ret;
 
        DPRINT_INFO(STORVSC, "resetting host adapter...");
@@ -625,6 +649,16 @@ int StorVscOnHostReset(struct hv_device *Device)
                return -1;
        }
 
+       spin_lock_irqsave(&storDevice->lock, flags);
+       storDevice->reset = 1;
+       spin_unlock_irqrestore(&storDevice->lock, flags);
+
+       /*
+        * Wait for traffic in transit to complete
+        */
+       while (atomic_read(&storDevice->NumOutstandingRequests))
+               udelay(1000);
+
        request = &storDevice->ResetRequest;
        vstorPacket = &request->VStorPacket;
 
-- 
1.6.0.2


_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/virtualization