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From:   Wenchao Hao <haowenchao@huawei.com>
To:     "James E . J . Bottomley" <jejb@linux.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        Doug Gilbert <dgilbert@interlog.com>
CC:     <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Wenchao Hao <haowenchao@huawei.com>
Subject: [RFC PATCH 5/5] scsi:scsi_debug: fail specific scsi command with result and sense data
Date:   Wed, 9 Nov 2022 10:59:50 -0500
Message-ID: <20221109155950.3536976-6-haowenchao@huawei.com>
In-Reply-To: <20221109155950.3536976-1-haowenchao@huawei.com>
References: <20221109155950.3536976-1-haowenchao@huawei.com>
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If a fail commnd error is injected for specific scsi command, set the
scsi command's status and sense data, then finish this scsi command.

For example, the following command would make read(0x88) command finished
with UNC for 8 times:

  error=/sys/block/sdb/device/error_inject/error
  echo "2 -8 0x88 0 0 0x2 0x3 0x11 0x0" >$error

Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
---
 drivers/scsi/scsi_debug.c | 46 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 217a9e892391..06fe2914117f 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7832,6 +7832,41 @@ static int sdebug_fail_queue_cmd(struct scsi_cmnd *cmnd)
 	return 0;
 }
 
+static int sdebug_fail_cmd(struct scsi_cmnd *cmnd, int *retval,
+			   struct sdebug_err_inject *info)
+{
+	struct scsi_device *sdp = cmnd->device;
+	struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata;
+	struct sdebug_err_inject *err;
+	unsigned char *cmd = cmnd->cmnd;
+	int ret = 0;
+	int result;
+
+	if (devip == NULL)
+		return 0;
+
+	list_for_each_entry(err, &devip->inject_err_list, list) {
+		if (err->type == ERR_FAIL_CMD &&
+		    (err->cmd == cmd[0] || err->cmd == 0xff)) {
+			if (!err->cnt)
+				return 0;
+			ret = !!err->cnt;
+			goto out_handle;
+		}
+	}
+	return 0;
+
+out_handle:
+	if (err->cnt < 0)
+		err->cnt++;
+	mk_sense_buffer(cmnd, err->sense_key, err->asc, err->asq);
+	result = err->status_byte | err->host_byte << 16 | err->driver_byte << 24;
+	*info = *err;
+	*retval = schedule_resp(cmnd, devip, result, NULL, 0, 0);
+
+	return ret;
+}
+
 static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 				   struct scsi_cmnd *scp)
 {
@@ -7852,6 +7887,7 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 	bool has_wlun_rl;
 	bool inject_now;
 	int ret = 0;
+	struct sdebug_err_inject err;
 
 	scsi_set_resid(scp, 0);
 	if (sdebug_statistics) {
@@ -7904,6 +7940,16 @@ static int scsi_debug_queuecommand(struct Scsi_Host *shost,
 		return ret;
 	}
 
+	if (sdebug_fail_cmd(scp, &ret, &err)) {
+		scmd_printk(KERN_INFO, scp,
+			"fail command 0x%x with hostbyte=0x%x, "
+			"driverbyte=0x%x, statusbyte=0x%x, "
+			"sense_key=0x%x, asc=0x%x, asq=0x%x\n",
+			opcode, err.host_byte, err.driver_byte,
+			err.status_byte, err.sense_key, err.asc, err.asq);
+		return ret;
+	}
+
 	if (unlikely(inject_now && !atomic_read(&sdeb_inject_pending)))
 		atomic_set(&sdeb_inject_pending, 1);
 
-- 
2.35.3