Re: [PATCH 2/2] RDMA/srp: Rework SCSI device reset handling

On 1/19/19 2:04 AM, Christoph Hellwig wrote:

...

• /* Check whether all requests have finished. */
• blk_freeze_queue_start(q);
• time_left = blk_mq_freeze_queue_wait_timeout(q, 1 * HZ);
• blk_mq_unfreeze_queue(q);

• return time_left > 0 ? SUCCESS : FAILED;

This is entirely generic SCSI/block evel functionality. I'd rather have a new WAIT_FOR_FREEZE return value from ->eh_device_reset_handler and handle this in the SCSI midlayer.

Hi Christoph,

Since a SCSI device must only reply to a reset task management function after all affected commands have completed, the only case in which that wait code is useful is if a regular reply is sent concurrently with the SCSI reset reply and the two replies get reordered. Since the SCSI error handler is able to deal with pending commands after a device reset, how about leaving out the queue freeze / unfreeze code?

Thanks,

Bart.