Although it is important to be able to trigger the code in the SCSI
core for SCSI_MLQUEUE_HOST_BUSY handling, currently it is
nontrivial to trigger that code. Hence this patch that adds a new
error injection option to the scsi_debug driver for making the
.queue_rq() implementation of this driver return
SCSI_MLQUEUE_HOST_BUSY.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
drivers/scsi/scsi_debug.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 9833850a53df..4b87e94e6611 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -161,12 +161,14 @@ static const char *sdebug_version_date = "20160430";
#define SDEBUG_OPT_N_WCE 0x1000
#define SDEBUG_OPT_RESET_NOISE 0x2000
#define SDEBUG_OPT_NO_CDB_NOISE 0x4000
+#define SDEBUG_OPT_HOST_BUSY 0x8000
#define SDEBUG_OPT_ALL_NOISE (SDEBUG_OPT_NOISE | SDEBUG_OPT_Q_NOISE | \
SDEBUG_OPT_RESET_NOISE)
#define SDEBUG_OPT_ALL_INJECTING (SDEBUG_OPT_RECOVERED_ERR | \
SDEBUG_OPT_TRANSPORT_ERR | \
SDEBUG_OPT_DIF_ERR | SDEBUG_OPT_DIX_ERR | \
- SDEBUG_OPT_SHORT_TRANSFER)
+ SDEBUG_OPT_SHORT_TRANSFER | \
+ SDEBUG_OPT_HOST_BUSY)
/* When "every_nth" > 0 then modulo "every_nth" commands:
* - a missing response is simulated if SDEBUG_OPT_TIMEOUT is set
* - a RECOVERED_ERROR is simulated on successful read and write
@@ -282,6 +284,7 @@ struct sdebug_queued_cmd {
unsigned int inj_dif:1;
unsigned int inj_dix:1;
unsigned int inj_short:1;
+ unsigned int inj_host_busy:1;
};
struct sdebug_queue {
@@ -3995,6 +3998,7 @@ static void setup_inject(struct sdebug_queue *sqp,
sqcp->inj_dif = !!(SDEBUG_OPT_DIF_ERR & sdebug_opts);
sqcp->inj_dix = !!(SDEBUG_OPT_DIX_ERR & sdebug_opts);
sqcp->inj_short = !!(SDEBUG_OPT_SHORT_TRANSFER & sdebug_opts);
+ sqcp->inj_host_busy = !!(SDEBUG_OPT_HOST_BUSY & sdebug_opts);
}
/* Complete the processing of the thread that queued a SCSI command to this
@@ -5278,6 +5282,12 @@ static bool fake_timeout(struct scsi_cmnd *scp)
return false;
}
+static bool fake_host_busy(struct scsi_cmnd *scp)
+{
+ return (sdebug_opts & SDEBUG_OPT_HOST_BUSY) &&
+ (atomic_read(&sdebug_cmnd_count) % abs(sdebug_every_nth)) == 0;
+}
+
static int scsi_debug_queuecommand(struct Scsi_Host *shost,
struct scsi_cmnd *scp)
{
@@ -5320,6 +5330,8 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
sdev_printk(KERN_INFO, sdp, "%s: cmd %s\n", my_name,
b);
}
+ if (fake_host_busy(scp))
+ return SCSI_MLQUEUE_HOST_BUSY;
has_wlun_rl = (sdp->lun == SCSI_W_LUN_REPORT_LUNS);
if (unlikely((sdp->lun >= sdebug_max_luns) && !has_wlun_rl))
goto err_out;
--
2.15.0
