[SCSI] fnic: fixing issues in device and firmware reset code
1. Handling overlapped firmware resets
This fix serialize multiple firmware resets to avoid situation where fnic
device fails to come up for link up event, when firmware resets are issued
back to back. If there are overlapped firmware resets are issued,
the firmware reset operation checks whether there is any firmware reset in
progress, if so it polls for its completion in a loop with 100ms delay.
2. Handling device reset timeout
fnic_device_reset code has been modified to handle Device reset timeout:
- Issue terminate on device reset timeout.
- Introduced flags field (one of the scratch fields in scsi_cmnd).
With this, device reset request would have DEVICE_RESET flag set for other
routines to determine the type of the request.
Also modified fnic_terminate_rport_io, fnic_rport_exch_rset, completion
routines to handle SCSI commands with DEVICE_RESET flag.
3. LUN/Device Reset hangs when issued through IOCTL using utilities like
sg_reset.
Each SCSI command is associated with a valid tag, fnic uses this tag to
retrieve associated scsi command on completion. the LUN/Device Reset issued
through IOCTL resulting into a SCSI command that is not associated with a
valid tag. So fnic fails to retrieve associated scsi command on completion,
which causes hang. This fix allocates tag, associates it with the
scsi command and frees the tag, when the operation completed.
4. Preventing IOs during firmware reset.
Current fnic implementation allows IO submissions during firmware reset.
This fix synchronizes IO submissions and firmware reset operations.
It ensures that IOs issued to fnic prior to reset will be issued to the
firmware before firmware reset.
projects / karo-tx-linux.git / commit