Re: [GIT PULL] Block driver changes for 3.20

[Jens Axboe <axboe@fb.com>]

On 02/12/2015 03:37 PM, Linus Torvalds wrote:
> On Thu, Feb 12, 2015 at 12:57 PM, Jens Axboe <axboe@fb.com> wrote:
>>
>> - Switching libata to use the new blk-mq tagging policy, removing code
>>    (and a suboptimal implementation) from libata. This will throw you a
>>    merge conflict, since a bug in the original libata tagging code was
>>    fixed since this code was branched. Trivial. From Shaohua.
>
> Somebody should still check my resolution, since the code had been
> moved to another file. Tejun / Dan, it's your commit 72dd299d5039
> ("libata: allow sata_sil24 to opt-out of tag ordered submission") that
> added a ATA_FLAG_LOWTAG, which conflicts with commit 98bd4be1ba95
> ("libata: move sas ata tag allocation to libata-scsi.c") that moved
> the code.
>
> I verified that it all looks sane, and still compiles, but somebody
> should verify that the tag allocation changes still *work*,
> particularly for that sata_sil24 case.
>
> (I haven't pushed out quite yet, I'm waiting for the rest to compile
> cleanly too, and then I'll do a local compile and boot to see that it
> all works for me, but I'm writing this as a heads-up)

When the code was moved, it also morphed into the sas specific tag 
allocation. And the LOWTAG part was for sil24, which doesn't call that 
code anymore. So either resolution is fine:

1) Drop the LOWTAG part of ata_sas_allocate_tag(), which is the easy 
resolve. Or,
2) Add the two LOWTAG lines in ata_sas_allocate_tag().

So don't worry too much about it, if it compiles, it's good...

-- 
Jens Axboe