scsi: add SG_SCSI_RESET_NO_ESCALATE flag to SG_SCSI_RESET ioctl

Further to a January 2013 thread titled: "[PATCH] SG_SCSI_RESET ioctl
should only perform requested operation" by Jeremy Linton a patch (v3)
is presented that expands the existing ioctl to include "no_escalate"
versions to the existing resets. This requires no changes to SCSI low
level drivers (LLDs); it adds several more finely tuned reset options
to the user space. For example:

   /* This call remains the same, with the same escalating semantics
    * if the device (LU) reset fail. That is: on failure to try a
    * target reset and if that fails, try a bus reset, and if that fails
    * try a host (i.e. LLD) reset. */
   val = SG_SCSI_RESET_DEVICE;
   res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val);

   /* What follows is a new option introduced by this patch series. Only
    * a device reset is attempted. If that fails then an appropriate
    * error code is provided. N.B. There is no reset escalation. */
   val = SG_SCSI_RESET_DEVICE | SG_SCSI_RESET_NO_ESCALATE;
   res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val);

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Jeremy Linton <jlinton@tributary.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Douglas Gilbert
2014-10-18 22:11:21 +02:00
committed by Christoph Hellwig
parent 678e275732
commit 26cf591e6d
5 changed files with 43 additions and 14 deletions

View File

@@ -2366,8 +2366,18 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
break;
/* FALLTHROUGH */
case SCSI_TRY_RESET_HOST:
case SCSI_TRY_RESET_HOST | SCSI_TRY_RESET_NO_ESCALATE:
rtn = scsi_try_host_reset(scmd);
break;
case SCSI_TRY_RESET_DEVICE | SCSI_TRY_RESET_NO_ESCALATE:
rtn = scsi_try_bus_device_reset(scmd);
break;
case SCSI_TRY_RESET_TARGET | SCSI_TRY_RESET_NO_ESCALATE:
rtn = scsi_try_target_reset(scmd);
break;
case SCSI_TRY_RESET_BUS | SCSI_TRY_RESET_NO_ESCALATE:
rtn = scsi_try_bus_reset(scmd);
break;
default:
rtn = FAILED;
}