Re: [PATCH 5/8] btrfs: cleanup scrub_rbio

[Christoph Hellwig <hch@lst.de>]

On Tue, Dec 13, 2022 at 04:53:33PM +0800, Qu Wenruo wrote:
>>     	ret = scrub_assemble_read_bios(rbio, &bio_list);
>>   	if (ret < 0)
>> -		goto cleanup;
>> +		return ret;
>>     	submit_read_bios(rbio, &bio_list);
>>   	wait_event(rbio->io_wait, atomic_read(&rbio->stripes_pending) == 0);
>>     	/* We may have some failures, recover the failed sectors first. */
>>   	ret = recover_scrub_rbio(rbio);
>> -	if (ret < 0)
>> -		goto cleanup;
>> +	if (ret < 0) {
>> +		while ((bio = bio_list_pop(&bio_list)))
>> +			bio_put(bio);
>> +		return ret;
>> +	}
>
> Do we still need the cleanup? IIRC after submit_read_bios() (or be more 
> safe, after wait_event()), we should no longer touch @bio_list anymore.

Oh, true.  submit_read_bios does the list_pop, so we don't need
this here, and in recover_rbio either.  And looking at it a little more
I think the are could use even more cleanup by:

 - moving the wait_event for stripes_pending into submit_read_bios.
 - moving the submit_read_bios *_assemble_read_bios and stop passing
   the bio_list entirely, which removes all the confusion about
   who cleans it up.

What do you think of this series (still needs testing before I can
post it):

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/btrfs-raid56-cleanups