[PATCH v6 5/7] scsi: scsi_debug: Support injecting unaligned write errors

[Bart Van Assche <bvanassche@acm.org>]

Allow user space software, e.g. a blktests test, to inject unaligned
write errors.

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_debug.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 57c6242bfb26..051b0605f11f 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -181,6 +181,7 @@ static const char *sdebug_version_date = "20210520";
 #define SDEBUG_OPT_NO_CDB_NOISE		0x4000
 #define SDEBUG_OPT_HOST_BUSY		0x8000
 #define SDEBUG_OPT_CMD_ABORT		0x10000
+#define SDEBUG_OPT_UNALIGNED_WRITE	0x20000
 #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 | \
@@ -188,7 +189,8 @@ static const char *sdebug_version_date = "20210520";
 				  SDEBUG_OPT_DIF_ERR | SDEBUG_OPT_DIX_ERR | \
 				  SDEBUG_OPT_SHORT_TRANSFER | \
 				  SDEBUG_OPT_HOST_BUSY | \
-				  SDEBUG_OPT_CMD_ABORT)
+				  SDEBUG_OPT_CMD_ABORT | \
+				  SDEBUG_OPT_UNALIGNED_WRITE)
 #define SDEBUG_OPT_RECOV_DIF_DIX (SDEBUG_OPT_RECOVERED_ERR | \
 				  SDEBUG_OPT_DIF_ERR | SDEBUG_OPT_DIX_ERR)
 
@@ -3587,6 +3589,14 @@ static int resp_write_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
 	struct sdeb_store_info *sip = devip2sip(devip, true);
 	u8 *cmd = scp->cmnd;
 
+	if (unlikely(sdebug_opts & SDEBUG_OPT_UNALIGNED_WRITE &&
+		     atomic_read(&sdeb_inject_pending))) {
+		atomic_set(&sdeb_inject_pending, 0);
+		mk_sense_buffer(scp, ILLEGAL_REQUEST, LBA_OUT_OF_RANGE,
+				UNALIGNED_WRITE_ASCQ);
+		return check_condition_result;
+	}
+
 	switch (cmd[0]) {
 	case WRITE_16:
 		ei_lba = 0;