scsi_debug: append inject error flags onto scsi_cmnd object

The way the existing scsi_debug command parser associated various
inject error flags to a command was difficult to replicate in the
table driven parser. This patch adds infrastructure to append those
flags to the end of a scsi_cmnd object with the cmd_size host
template option.
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/scsi_debug.c

@@ -209,6 +209,14 @@ static const char *scsi_debug_version_date = "20141022";
 #warning "Expect DEF_CMD_PER_LUN <= SCSI_DEBUG_CANQUEUE"
 #endif
 
+struct sdebug_scmd_extra_t {
+	bool inj_recovered;
+	bool inj_transport;
+	bool inj_dif;
+	bool inj_dix;
+	bool inj_short;
+};
+
 static int scsi_debug_add_host = DEF_NUM_HOST;
 static int scsi_debug_ato = DEF_ATO;
 static int scsi_debug_delay = DEF_DELAY;
@@ -248,6 +256,7 @@ static unsigned int scsi_debug_write_same_length = DEF_WRITESAME_LENGTH;
 static bool scsi_debug_removable = DEF_REMOVABLE;
 static bool scsi_debug_clustering;
 static bool scsi_debug_host_lock = DEF_HOST_LOCK;
+static bool sdebug_any_injecting_opt;
 
 static atomic_t sdebug_cmnd_count;
 static atomic_t sdebug_completions;
@@ -3416,6 +3425,16 @@ static ssize_t opts_store(struct device_driver *ddp, const char *buf,
 	return -EINVAL;
 opts_done:
 	scsi_debug_opts = opts;
+	if (SCSI_DEBUG_OPT_RECOVERED_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_TRANSPORT_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_DIF_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_DIX_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_SHORT_TRANSFER & opts)
+		sdebug_any_injecting_opt = true;
 	atomic_set(&sdebug_cmnd_count, 0);
 	atomic_set(&sdebug_a_tsf, 0);
 	return count;
@@ -4563,6 +4582,41 @@ sdebug_change_qtype(struct scsi_device *sdev, int qtype)
 	return qtype;
 }
 
+static int
+check_inject(struct scsi_cmnd *scp)
+{
+	struct sdebug_scmd_extra_t *ep = scsi_cmd_priv(scp);
+
+	memset(ep, 0, sizeof(struct sdebug_scmd_extra_t));
+
+	if (atomic_inc_return(&sdebug_cmnd_count) >=
+	    abs(scsi_debug_every_nth)) {
+		atomic_set(&sdebug_cmnd_count, 0);
+		if (scsi_debug_every_nth < -1)
+			scsi_debug_every_nth = -1;
+		if (SCSI_DEBUG_OPT_TIMEOUT & scsi_debug_opts)
+			return 1; /* ignore command causing timeout */
+		else if (SCSI_DEBUG_OPT_MAC_TIMEOUT & scsi_debug_opts &&
+			 scsi_medium_access_command(scp))
+			return 1; /* time out reads and writes */
+		if (sdebug_any_injecting_opt) {
+			int opts = scsi_debug_opts;
+
+			if (SCSI_DEBUG_OPT_RECOVERED_ERR & opts)
+				ep->inj_recovered = true;
+			else if (SCSI_DEBUG_OPT_TRANSPORT_ERR & opts)
+				ep->inj_transport = true;
+			else if (SCSI_DEBUG_OPT_DIF_ERR & opts)
+				ep->inj_dif = true;
+			else if (SCSI_DEBUG_OPT_DIX_ERR & opts)
+				ep->inj_dix = true;
+			else if (SCSI_DEBUG_OPT_SHORT_TRANSFER & opts)
+				ep->inj_short = true;
+		}
+	}
+	return 0;
+}
+
 static struct scsi_host_template sdebug_driver_template = {
 	.show_info =		scsi_debug_show_info,
 	.write_info =		scsi_debug_write_info,
@@ -4589,11 +4643,13 @@ static struct scsi_host_template sdebug_driver_template = {
 	.use_clustering = 	DISABLE_CLUSTERING,
 	.module =		THIS_MODULE,
 	.track_queue_depth =	1,
+	.cmd_size =		sizeof(struct sdebug_scmd_extra_t),
 };
 
 static int sdebug_driver_probe(struct device * dev)
 {
 	int error = 0;
+	int opts;
 	struct sdebug_host_info *sdbg_host;
 	struct Scsi_Host *hpnt;
 	int host_prot;
@@ -4662,6 +4718,18 @@ static int sdebug_driver_probe(struct device * dev)
 	else
 		scsi_host_set_guard(hpnt, SHOST_DIX_GUARD_CRC);
 
+	opts = scsi_debug_opts;
+	if (SCSI_DEBUG_OPT_RECOVERED_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_TRANSPORT_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_DIF_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_DIX_ERR & opts)
+		sdebug_any_injecting_opt = true;
+	else if (SCSI_DEBUG_OPT_SHORT_TRANSFER & opts)
+		sdebug_any_injecting_opt = true;
+
         error = scsi_add_host(hpnt, &sdbg_host->dev);
         if (error) {
                 printk(KERN_ERR "%s: scsi_add_host failed\n", __func__);