| SCSI_RESET(9F) | Kernel Functions for Drivers | SCSI_RESET(9F) |
scsi_reset - reset a SCSI bus or target
#include <sys/scsi/scsi.h> int scsi_reset(struct scsi_address *ap, int level);
illumos DDI specific (illumos DDI).
ap
level
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.
The scsi_reset() function returns:
1
0
The scsi_reset() function can be called from user, interrupt, or kernel context.
tran_reset(9E), tran_reset_notify(9E), scsi_abort(9F)
Writing Device Drivers
| January 16, 2006 | OmniOS |