Re: [PATCH v6 01/13] block: Generalized bio pool freeing

From: Nicholas A. Bellinger
Date: Wed Aug 22 2012 - 17:27:02 EST


On Wed, 2012-08-22 at 10:03 -0700, Kent Overstreet wrote:
> With the old code, when you allocate a bio from a bio pool you have to
> implement your own destructor that knows how to find the bio pool the
> bio was originally allocated from.
>
> This adds a new field to struct bio (bi_pool) and changes
> bio_alloc_bioset() to use it. This makes various bio destructors
> unnecessary, so they're then deleted.
>
> v6: Explain the temporary if statement in bio_put
>
> Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
> CC: Jens Axboe <axboe@xxxxxxxxx>
> CC: NeilBrown <neilb@xxxxxxx>
> CC: Alasdair Kergon <agk@xxxxxxxxxx>
> CC: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> CC: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
> Acked-by: Tejun Heo <tj@xxxxxxxxxx>
> ---
> drivers/block/drbd/drbd_main.c | 13 +------------
> drivers/md/dm-crypt.c | 9 ---------
> drivers/md/dm-io.c | 11 -----------
> drivers/md/dm.c | 20 --------------------
> drivers/md/md.c | 28 ++++------------------------
> drivers/target/target_core_iblock.c | 9 ---------
> fs/bio.c | 31 +++++++++++++------------------
> include/linux/blk_types.h | 3 +++
> 8 files changed, 21 insertions(+), 103 deletions(-)
>

<SNIP>

> diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
> index 76db75e..e58cd7d 100644
> --- a/drivers/target/target_core_iblock.c
> +++ b/drivers/target/target_core_iblock.c
> @@ -543,14 +543,6 @@ static void iblock_complete_cmd(struct se_cmd *cmd)
> kfree(ibr);
> }
>
> -static void iblock_bio_destructor(struct bio *bio)
> -{
> - struct se_cmd *cmd = bio->bi_private;
> - struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
> -
> - bio_free(bio, ib_dev->ibd_bio_set);
> -}
> -
> static struct bio *
> iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
> {
> @@ -572,7 +564,6 @@ iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
>
> bio->bi_bdev = ib_dev->ibd_bd;
> bio->bi_private = cmd;
> - bio->bi_destructor = iblock_bio_destructor;
> bio->bi_end_io = &iblock_bio_done;
> bio->bi_sector = lba;
> return bio;

The change to drop iblock_bio_destructor() looks fine to me. For the
drivers/target/ bit, feel free to add:

Acked-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

Nice work Kent!

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