On Fri, Mar 10 2017 at 10:07am -0500,
Jack Wang <jinpu.wang@xxxxxxxxxxxxxxxx> wrote:
>
>
> On 10.03.2017 15:55, Mikulas Patocka wrote:
> >
> >
> > On Fri, 10 Mar 2017, Mike Snitzer wrote:
> >
> >> On Fri, Mar 10 2017 at 7:34am -0500,
> >> Lars Ellenberg <lars.ellenberg@xxxxxxxxxx> wrote:
> >>
> >>>> --- a/block/blk-core.c
> >>>> +++ b/block/blk-core.c
> >>>> @@ -1975,7 +1975,14 @@ generic_make_request_checks(struct bio *bio)
> >>>> */
> >>>> blk_qc_t generic_make_request(struct bio *bio)
> >>>> {
> >>>> - struct bio_list bio_list_on_stack;
> >>>> + /*
> >>>> + * bio_list_on_stack[0] contains bios submitted by the current
> >>>> + * make_request_fn.
> >>>> + * bio_list_on_stack[1] contains bios that were submitted before
> >>>> + * the current make_request_fn, but that haven't been processed
> >>>> + * yet.
> >>>> + */
> >>>> + struct bio_list bio_list_on_stack[2];
> >>>> blk_qc_t ret = BLK_QC_T_NONE;
> >>>
> >>> May I suggest that, if you intend to assign something that is not a
> >>> plain &(struct bio_list), but a &(struct bio_list[2]),
> >>> you change the task member so it is renamed (current->bio_list vs
> >>> current->bio_lists, plural, is what I did last year).
> >>> Or you will break external modules, silently, and horribly (or,
> >>> rather, they won't notice, but break the kernel).
> >>> Examples of such modules would be DRBD, ZFS, quite possibly others.
> >>
> >> drbd is upstream -- so what is the problem? (if you are having to
> >> distribute drbd independent of the upstream drbd then why is drbd
> >> upstream?)
> >>
> >> As for ZFS, worrying about ZFS kABI breakage is the last thing we should
> >> be doing.
> >
> > It's better to make external modules not compile than to silently
> > introduce bugs in them. So yes, I would rename that.
> >
> > Mikulas
>
> Agree, better rename current->bio_list to current->bio_lists
Fine, normally wouldn't do so but I'm not so opposed that we need to get
hung up on this detail. If Neil and Jens agree then so be it.
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