scsi: scsi_debug: Set command result and sense data if error is injected

If a fail command error is injected, set the command's status and sense
data then finish this SCSI command.

Set SCSI command's status and sense data format:

  +--------+------+-------------------------------------------------------+
  | Column | Type | Description                                           |
  +--------+------+-------------------------------------------------------+
  |   1    |  u8  | Error type, fixed to 0x2                              |
  +--------+------+-------------------------------------------------------+
  |   2    |  s32 | Error Count                                           |
  |        |      |  0: the rule will be ignored                          |
  |        |      |  positive: the rule will always take effect           |
  |        |      |  negative: the rule takes effect n times where -n is  |
  |        |      |            the value given. Ignored after n times     |
  +--------+------+-------------------------------------------------------+
  |   3    |  x8  | SCSI command opcode, 0xff for all commands            |
  +--------+------+-------------------------------------------------------+
  |   4    |  x8  | Host byte in scsi_cmd::status                         |
  |        |      | [scsi_cmd::status has 32 bits holding these 3 bytes]  |
  +--------+------+-------------------------------------------------------+
  |   5    |  x8  | Driver byte in scsi_cmd::status                       |
  +--------+------+-------------------------------------------------------+
  |   6    |  x8  | SCSI Status byte in scsi_cmd::status                  |
  +--------+------+-------------------------------------------------------+
  |   7    |  x8  | SCSI Sense Key in scsi_cmnd                           |
  +--------+------+-------------------------------------------------------+
  |   8    |  x8  | SCSI ASC in scsi_cmnd                                 |
  +--------+------+-------------------------------------------------------+
  |   9    |  x8  | SCSI ASCQ in scsi_cmnd                                |
  +--------+------+-------------------------------------------------------+

Examples:
    error=/sys/kernel/debug/scsi_debug/0:0:0:1/error
    echo "2 -10 0x88 0 0 0x2 0x3 0x11 0x0" >${error}

will make device's read command return with media error with additional
sense of "Unrecovered read error" (UNC):

Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
Link: https://lore.kernel.org/r/20231010092051.608007-7-haowenchao2@huawei.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index efdd63dd6d25deadde80745e4eecdf4bcbd57e1c..d15d007f13178e34ee7b58bbb058631ca53eed0d 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7797,6 +7797,48 @@ 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;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(err, &devip->inject_err_list, list) {
+               if (err->type == ERR_FAIL_CMD &&
+                   (err->cmd == cmd[0] || err->cmd == 0xff)) {
+                       if (!err->cnt) {
+                               rcu_read_unlock();
+                               return 0;
+                       }
+
+                       ret = !!err->cnt;
+                       rcu_read_unlock();
+                       goto out_handle;
+               }
+       }
+       rcu_read_unlock();
+
+       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)
 {
@@ -7817,6 +7859,7 @@ 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) {
@@ -7869,6 +7912,16 @@ 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);