From 66d6afec5a89464880e7793ad1b791cbee1efd8d Mon Sep 17 00:00:00 2001
From: Michael Lotz <mmlr@mlotz.ch>
Date: Sun, 1 Sep 2019 01:57:52 +0200
Subject: [PATCH] virtio_scsi: Abort requests on timeout.

Previously the CCB would never complete when a timeout occured, leading
to all further IO stopping.

Abort the request by setting the CCB status to aborted and handing the
CCB back to the SCSI layer. That one will then handle the error (and
possibly retrying). This is similar to how such errors are handled in
AHCI and the ATA stack.

Since it is now possible that we receive a completion interrupt for an
already aborted request, we need to keep track of what request the
interrupts belong to and only notify when the current one completes. As
there currently can't be multiple requests in flight, a simple counter
is used.

Change-Id: Ib80e146605efd2f81123803f424cc7f66f52a6c8
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1815
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
---
 .../scsi/virtio/VirtioSCSIController.cpp      | 20 +++++++++++--------
 .../busses/scsi/virtio/VirtioSCSIPrivate.h    |  2 ++
 .../busses/scsi/virtio/VirtioSCSIRequest.cpp  | 11 ++++++++++
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIController.cpp b/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIController.cpp
index 59fa80b6c4..5082f1342f 100644
--- a/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIController.cpp
+++ b/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIController.cpp
@@ -37,6 +37,7 @@ VirtioSCSIController::VirtioSCSIController(device_node *node)
 	fVirtioDevice(NULL),
 	fStatus(B_NO_INIT),
 	fRequest(NULL),
+	fCurrentRequest(0),
 	fEventDPC(NULL)
 {
 	CALLED();
@@ -230,16 +231,20 @@ VirtioSCSIController::ExecuteRequest(scsi_ccb *ccb)
 	}
 	fRequest->FillRequest(inCount, outCount, entries);
 
+	atomic_add(&fCurrentRequest, 1);
 	fInterruptCondition.Add(&fInterruptConditionEntry);
 
 	fVirtio->queue_request_v(fRequestVirtioQueue, entries,
-		outCount, inCount, NULL);
+		outCount, inCount, (void *)(addr_t)fCurrentRequest);
 
 	result = fInterruptConditionEntry.Wait(B_RELATIVE_TIMEOUT,
 		fRequest->Timeout());
 
-	if (result != B_OK)
+	if (result != B_OK) {
+		ERROR("wait failed with status: %#" B_PRIx32 "\n", result);
+		fRequest->Abort();
 		return result;
+	}
 
 	return fRequest->Finish(false);
 }
@@ -273,11 +278,6 @@ VirtioSCSIController::_RequestCallback(void* driverCookie, void* cookie)
 {
 	CALLED();
 	VirtioSCSIController* controller = (VirtioSCSIController*)driverCookie;
-
-	while (controller->fVirtio->queue_dequeue(
-			controller->fRequestVirtioQueue, NULL, NULL)) {
-	}
-
 	controller->_RequestInterrupt();
 }
 
@@ -285,7 +285,11 @@ VirtioSCSIController::_RequestCallback(void* driverCookie, void* cookie)
 void
 VirtioSCSIController::_RequestInterrupt()
 {
-	fInterruptCondition.NotifyAll();
+	void* cookie = NULL;
+	while (fVirtio->queue_dequeue(fRequestVirtioQueue, &cookie, NULL)) {
+		if ((int32)(addr_t)cookie == atomic_get(&fCurrentRequest))
+			fInterruptCondition.NotifyAll();
+	}
 }
 
 
diff --git a/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIPrivate.h b/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIPrivate.h
index 78413e4d3a..a7afe88552 100644
--- a/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIPrivate.h
+++ b/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIPrivate.h
@@ -91,6 +91,7 @@ private:
 
 			VirtioSCSIRequest*	fRequest;
 
+			int32				fCurrentRequest;
 			ConditionVariable	fInterruptCondition;
 			ConditionVariableEntry fInterruptConditionEntry;
 
@@ -123,6 +124,7 @@ public:
 									{ return fCCB->data_length > 0; }
 
 			status_t			Finish(bool resubmit);
+			void				Abort();
 
 			// SCSI stuff
 			status_t			Start(scsi_ccb *ccb);
diff --git a/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIRequest.cpp b/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIRequest.cpp
index ff4244b6b3..49071609e7 100644
--- a/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIRequest.cpp
+++ b/src/add-ons/kernel/busses/scsi/virtio/VirtioSCSIRequest.cpp
@@ -140,6 +140,17 @@ VirtioSCSIRequest::Finish(bool resubmit)
 }
 
 
+void
+VirtioSCSIRequest::Abort()
+{
+	scsi_ccb *ccb = fCCB;
+	mutex_unlock(&fLock);
+
+	ccb->subsys_status = SCSI_REQ_ABORTED;
+	gSCSI->finished(ccb, 1);
+}
+
+
 void
 VirtioSCSIRequest::RequestSense()
 {