Further to the thread titled: "[PATCH] SG_SCSI_RESET ioctl should
only perform requested operation" by Jeremy Linton a patch (v2)
is presented that adds "no_escalate" versions to the existing
ioctl. 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. 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);

This patches applies to lk 3.7.8 and lk 3.8.0-rc7 . I will extend
sg_reset in the sg3_utils package to use it. Note the bsg driver
does not support the SG_SCSI_RESET ioctl and that continues to
be the case.
v2 of this patch modifies the SG_SCSI_RESET ioctl in scsi_ioctl.c
so block device nodes (e.g. /dev/sdb) have this additional
functionality.

ChangeLog:
   - modify SG_SCSI_RESET ioctl so the SG_SCSI_RESET_NO_ESCALATE
     value may be added to the existing values. If so the existing
     device->target->bus->host escalation does not occur. The
     SG_SCSI_RESET ioctl is modified in both the sg driver and
     scsi_ioctl.c (so block devices can use it).
   - modify scsi_reset_provider() in the scsi_error.c file in a
     similar way to support this additional functionality.

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>