Re: [PATCH 02/12] xfs: simplify xfs_chain_bio

Darrick J. Wong
2019-06-24T15:15:34Z

On Mon, Jun 24, 2019 at 07:52:43AM +0200, Christoph Hellwig wrote:
> Move setting up operation and write hint to xfs_alloc_ioend, and
> then just copy over all needed information from the previous bio
> in xfs_chain_bio and stop passing various parameters to it.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

I always thought it was a little odd that we were still setting bio
fields in the submission function...

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> fs/xfs/xfs_aops.c | 35 +++++++++++++++++------------------
> 1 file changed, 17 insertions(+), 18 deletions(-)
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index a6f0f4761a37..9cceb90e77c5 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -665,7 +665,6 @@ xfs_submit_ioend(
>
> ioend->io_bio->bi_private = ioend;
> ioend->io_bio->bi_end_io = xfs_end_bio;
> - ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
>
> /*
> * If we are failing the IO now, just mark the ioend with an
> @@ -679,7 +678,6 @@ xfs_submit_ioend(
> return status;
> }
>
> - ioend->io_bio->bi_write_hint = ioend->io_inode->i_write_hint;
> submit_bio(ioend->io_bio);
> return 0;
> }
> @@ -691,7 +689,8 @@ xfs_alloc_ioend(
> xfs_exntst_t state,
> xfs_off_t offset,
> struct block_device *bdev,
> - sector_t sector)
> + sector_t sector,
> + struct writeback_control *wbc)
> {
> struct xfs_ioend *ioend;
> struct bio *bio;
> @@ -699,6 +698,8 @@ xfs_alloc_ioend(
> bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, &xfs_ioend_bioset);
> bio_set_dev(bio, bdev);
> bio->bi_iter.bi_sector = sector;
> + bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
> + bio->bi_write_hint = inode->i_write_hint;
>
> ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
> INIT_LIST_HEAD(&ioend->io_list);
> @@ -719,24 +720,22 @@ xfs_alloc_ioend(
> * so that the bi_private linkage is set up in the right direction for the
> * traversal in xfs_destroy_ioend().
> */
> -static void
> +static struct bio *
> xfs_chain_bio(
> - struct xfs_ioend *ioend,
> - struct writeback_control *wbc,
> - struct block_device *bdev,
> - sector_t sector)
> + struct bio *prev)
> {
> struct bio *new;
>
> new = bio_alloc(GFP_NOFS, BIO_MAX_PAGES);
> - bio_set_dev(new, bdev);
> - new->bi_iter.bi_sector = sector;
> - bio_chain(ioend->io_bio, new);
> - bio_get(ioend->io_bio); /* for xfs_destroy_ioend */
> - ioend->io_bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
> - ioend->io_bio->bi_write_hint = ioend->io_inode->i_write_hint;
> - submit_bio(ioend->io_bio);
> - ioend->io_bio = new;
> + bio_copy_dev(new, prev);
> + new->bi_iter.bi_sector = bio_end_sector(prev);
> + new->bi_opf = prev->bi_opf;
> + new->bi_write_hint = prev->bi_write_hint;
> +
> + bio_chain(prev, new);
> + bio_get(prev); /* for xfs_destroy_ioend */
> + submit_bio(prev);
> + return new;
> }
>
> /*
> @@ -771,14 +770,14 @@ xfs_add_to_ioend(
> if (wpc->ioend)
> list_add(&wpc->ioend->io_list, iolist);
> wpc->ioend = xfs_alloc_ioend(inode, wpc->fork,
> - wpc->imap.br_state, offset, bdev, sector);
> + wpc->imap.br_state, offset, bdev, sector, wbc);
> }
>
> if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff, true)) {
> if (iop)
> atomic_inc(&iop->write_count);
> if (bio_full(wpc->ioend->io_bio))
> - xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
> + wpc->ioend->io_bio = xfs_chain_bio(wpc->ioend->io_bio);
> bio_add_page(wpc->ioend->io_bio, page, len, poff);
> }
>
> --
> 2.20.1
>