From 8c6d7671937fa581e2c7d1723a0b0e4631706dea Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@sandisk.com>
Date: Wed, 15 Apr 2015 17:27:13 +0200
Subject: [PATCH] scst_lib: Fix SCSI pass-through error handling

Some but not all SCSI LLD drivers set req->errors. Some SCSI
LLD drivers set req->errors to a negative Unix error code and
others assign the result of make_status_bytes() to req->errors.
The SCSI core finishes failed pass-through requests by calling
blk_finish_request(). That function calls req->end_io() without
setting req->errors. Hence check both the error argument and
req->errors before calling sioc->done().

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
---
 scst/src/dev_handlers/scst_disk.c |  4 +++-
 scst/src/scst_lib.c               | 12 +++++++++---
 scst/src/scst_targ.c              |  2 ++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/scst/src/dev_handlers/scst_disk.c b/scst/src/dev_handlers/scst_disk.c
index 3b85ae15b..7f7f05319 100644
--- a/scst/src/dev_handlers/scst_disk.c
+++ b/scst/src/dev_handlers/scst_disk.c
@@ -355,7 +355,9 @@ static void disk_cmd_done(void *data, char *sense, int result, int resid)
 	TRACE_DBG("work %p, cmd %p, left %d, result %d, sense %p, resid %d",
 		work, work->cmd, work->left, result, sense, resid);
 
-	if (result == SAM_STAT_GOOD)
+	WARN_ON_ONCE(IS_ERR_VALUE(result));
+
+	if (status_byte(result) == GOOD)
 		goto out_complete;
 
 	work->result = result;
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index dcbed6278..b4f648568 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -6740,8 +6740,10 @@ out:
 static void scsi_end_async(struct request *req, int error)
 {
 	struct scsi_io_context *sioc = req->end_io_data;
+	int errors;
 
-	TRACE_DBG("sioc %p, cmd %p", sioc, sioc->data);
+	TRACE_DBG("sioc %p, cmd %p, error %d / %d", sioc, sioc->data, error,
+		  req->errors);
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 17, 0)
 	lockdep_assert_held(req->q->queue_lock);
@@ -6750,11 +6752,15 @@ static void scsi_end_async(struct request *req, int error)
 		lockdep_assert_held(req->q->queue_lock);
 #endif
 
+	errors = req->errors && !IS_ERR_VALUE(req->errors) ? req->errors :
+		IS_ERR_VALUE(req->errors) || error ?
+		SAM_STAT_CHECK_CONDITION : 0;
+
 	if (sioc->done)
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 30)
-		sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
+		sioc->done(sioc->data, sioc->sense, errors, req->data_len);
 #else
-		sioc->done(sioc->data, sioc->sense, req->errors, req->resid_len);
+		sioc->done(sioc->data, sioc->sense, errors, req->resid_len);
 #endif
 
 	kmem_cache_free(scsi_io_context_cache, sioc);
diff --git a/scst/src/scst_targ.c b/scst/src/scst_targ.c
index bed46ed5d..79247a4e5 100644
--- a/scst/src/scst_targ.c
+++ b/scst/src/scst_targ.c
@@ -1724,6 +1724,8 @@ static void scst_do_cmd_done(struct scst_cmd *cmd, int result,
 
 	scst_set_exec_time(cmd);
 
+	WARN_ON_ONCE(IS_ERR_VALUE(result));
+
 	cmd->status = result & 0xff;
 	cmd->msg_status = msg_byte(result);
 	cmd->host_status = host_byte(result);