Re: [PATCH v3 03/30] block: Remove req_bio_endio()

[Damien Le Moal <dlemoal@kernel.org>]

On 3/29/24 06:28, Bart Van Assche wrote:
> On 3/27/24 5:43 PM, Damien Le Moal wrote:
>> Moving req_bio_endio() code into its only caller, blk_update_request(),
>> allows reducing accesses to and tests of bio and request fields. Also,
>> given that partial completions of zone append operations is not
>> possible and that zone append operations cannot be merged, the update
>> of the BIO sector using the request sector for these operations can be
>> moved directly before the call to bio_endio().
> 
> Reviewed-by: Bart Van Assche <bvanassche@acm.org>
> 
>> -	if (unlikely(error && !blk_rq_is_passthrough(req) &&
>> -		     !(req->rq_flags & RQF_QUIET)) &&
>> -		     !test_bit(GD_DEAD, &req->q->disk->state)) {
>> +	if (unlikely(error && !blk_rq_is_passthrough(req) && !quiet) &&
>> +	    !test_bit(GD_DEAD, &req->q->disk->state)) {
> 
> A question that is independent of this patch series: is it a bug or is
> it a feature that the GD_DEAD bit test is not marked as "unlikely"?

likely/unlikely are optimizations... I guess that bit test could be under
unlikely() as well. Though if we are dealing with a removable media device, this
may not be appropriate, which may be why it is not under unlikely(). Not sure.

> 
> Thanks,
> 
> Bart.

-- 
Damien Le Moal
Western Digital Research