On Fri, Apr 24, 2020 at 12:41:36PM +0200, Christoph Hellwig wrote:
> On Fri, Apr 24, 2020 at 06:23:48PM +0800, Ming Lei wrote:
> > +/* complete requests which just requires one flush command */
> > +static void blk_complete_flush_requests(struct blk_flush_queue *fq,
> > + struct list_head *flush_list)
> > +{
> > + struct block_device *bdev;
> > + struct request *rq;
> > + int error = -ENXIO;
> > +
> > + if (list_empty(flush_list))
> > + return;
> > +
> > + rq = list_first_entry(flush_list, struct request, queuelist);
> > +
> > + /* Send flush via one active hctx so we can move on */
> > + bdev = bdget_disk(rq->rq_disk, 0);
> > + if (bdev) {
> > + error = blkdev_issue_flush(bdev, GFP_KERNEL, NULL);
> > + bdput(bdev);
> > + }
>
> FYI, we don't really need the bdev to send a bio anymore, this could just
> do:
>
> bio = bio_alloc(GFP_KERNEL, 0); // XXX: shouldn't this be GFP_NOIO??
Error handling.
> bio->bi_disk = rq->rq_disk;
> bio->bi_partno = 0;
> bio_associate_blkg(bio); // XXX: actually, shouldn't this come from rq?
> bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
> error = submit_bio_wait(bio);
> bio_put(bio);
Yeah, that is another way, however I prefer to blkdev_issue_flush
because it takes less code and we do have the API of blkdev_issue_flush.
Thanks,
Ming
