SCSI_RESET(9F) Kernel Functions for Drivers SCSI_RESET(9F)
NAME
scsi_reset - reset a SCSI bus or target
SYNOPSIS
#include <sys/scsi/scsi.h>
int scsi_reset(
struct scsi_address *ap,
int level);
INTERFACE LEVEL
illumos DDI specific (illumos DDI).
PARAMETERS
ap Pointer to the
scsi_address structure.
level The level of reset required.
DESCRIPTION
The
scsi_reset() function asks the host adapter driver to reset the
SCSI bus or a
SCSI target as specified by
level. If
level equals
RESET_ALL, the
SCSI bus is reset. If it equals
RESET_TARGET,
ap is
used to determine the target to be reset. If it equals
RESET_LUN,
ap is used to determine the logical unit to be reset.
When given the
RESET_LUN level,
scsi_reset() can return failure if
the
LOGICAL UNIT RESET message is not supported by the target device,
or if the underlying HBA driver does not implement the ability to
issue a
LOGICAL UNIT RESET message.
Note that, at the point when
scsi_reset() resets the logical unit
(case
RESET_LUN), or the target (case
RESET_TARGET), or the bus (case
RESET_ALL), there might be one or more command packets outstanding.
That is, packets have been passed to
scsi_transport(), and queued or
possibly transported, but the commands have not been completed and
the target completion routine has not been called for those packets.
The successful call to
scsi_reset() has the side effect that any such
commands currently outstanding are aborted, at which point the
packets are marked with
pkt_reason set to
CMD_RESET, and the
appropriate bit -- either
STAT_BUS_RESET or
STAT_DEV_RESET -- is set
in
pkt_statistics. Once thus appropriately marked, the aborted
command packets are passed to the target driver command completion
routine.
Also note that, at the moment that a thread executing
scsi_reset() actually resets the target or the bus, it is possible that a second
thread may have already called
scsi_transport(), but not yet queued
or transported its command. In this case the HBA will not yet have
received the second thread's packet and this packet will not be
aborted.
RETURN VALUES
The
scsi_reset() function returns:
1 Upon success.
0 Upon failure.
CONTEXT
The
scsi_reset() function can be called from user, interrupt, or
kernel context.
SEE ALSO
tran_reset(9E),
tran_reset_notify(9E),
scsi_abort(9F) Writing Device Drivers January 16, 2006 SCSI_RESET(9F)
