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[RFC,00/34] block: introduce bio_new()

Message ID 20210128071133.60335-1-chaitanya.kulkarni@wdc.com
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Series block: introduce bio_new() | expand

Message

Chaitanya Kulkarni Jan. 28, 2021, 7:10 a.m. UTC 
Hi,

This is a *compile only RFC* which adds a generic helper to initialize
the various fields of the bio that is repeated all the places in
file-systems, block layer, and drivers.

The new helper allows callers to initialize non-optional members of bio
such as bdev, sector, op, opflags, max_bvecs and gfp_mask by
encapsulating new bio allocation with bio alloc with initialization
at one place.

The objective of this RFC is to only start a discussion, this it not 
completely tested at all.

-ck                         

Chaitanya Kulkarni (34):
  block: move common code into blk_next_bio()
  block: introduce and use bio_new
  drdb: use bio_new in drdb
  drdb: use bio_new() in submit_one_flush
  xen-blkback: use bio_new
  zram: use bio_new
  dm: use bio_new in dm-log-writes
  dm-zoned: use bio_new in get_mblock_slow
  dm-zoned: use bio_new in dmz_write_mblock
  dm-zoned: use bio_new in dmz_rdwr_block
  nvmet: use bio_new in nvmet_bdev_execute_rw
  scsi: target/iblock: use bio_new
  block: use bio_new in __blkdev_direct_IO
  fs/buffer: use bio_new in submit_bh_wbc
  fscrypt: use bio_new in fscrypt_zeroout_range
  fs/direct-io: use bio_new in dio_bio_alloc
  iomap: use bio_new in iomap_dio_zero
  iomap: use bio_new in iomap_dio_bio_actor
  fs/jfs/jfs_logmgr.c: use bio_new in lbmRead
  fs/jfs/jfs_logmgr.c: use bio_new in lbmStartIO
  fs/jfs/jfs_metapage.c: use bio_new in metapage_writepage
  fs/jfs/jfs_metapage.c: use bio_new in metapage_readpage
  fs/mpage.c: use bio_new mpage_alloc
  fs/nilfs: use bio_new nilfs_alloc_seg_bio
  ocfs/cluster: use bio_new in dm-log-writes
  xfs: use bio_new in xfs_rw_bdev
  xfs: use bio_new in xfs_buf_ioapply_map
  zonefs: use bio_new
  power/swap: use bio_new in hib_submit_io
  hfsplus: use bio_new in hfsplus_submit_bio()
  iomap: use bio_new in iomap_readpage_actor
  mm: use bio_new in __swap_writepage
  mm: use bio_new in swap_readpage
  mm: add swap_bio_new common bio helper

 block/blk-lib.c                     | 34 ++++++++++-------------------
 block/blk-zoned.c                   |  4 +---
 block/blk.h                         |  5 +++--
 drivers/block/drbd/drbd_receiver.c  | 12 +++++-----
 drivers/block/xen-blkback/blkback.c | 20 +++++++++++------
 drivers/block/zram/zram_drv.c       |  5 ++---
 drivers/md/dm-log-writes.c          | 30 +++++++++----------------
 drivers/md/dm-zoned-metadata.c      | 18 +++++----------
 drivers/nvme/target/io-cmd-bdev.c   |  9 +++-----
 drivers/target/target_core_iblock.c |  5 ++---
 fs/block_dev.c                      |  6 ++---
 fs/buffer.c                         | 16 ++++++--------
 fs/crypto/bio.c                     |  5 ++---
 fs/direct-io.c                      |  6 ++---
 fs/hfsplus/wrapper.c                |  5 +----
 fs/iomap/buffered-io.c              | 12 +++++-----
 fs/iomap/direct-io.c                | 11 ++++------
 fs/jfs/jfs_logmgr.c                 | 13 ++++-------
 fs/jfs/jfs_metapage.c               | 15 +++++--------
 fs/mpage.c                          | 18 +++++----------
 fs/nilfs2/segbuf.c                  | 10 ++-------
 fs/ocfs2/cluster/heartbeat.c        |  6 ++---
 fs/xfs/xfs_bio_io.c                 |  7 ++----
 fs/xfs/xfs_buf.c                    |  6 ++---
 fs/zonefs/super.c                   |  6 ++---
 include/linux/bio.h                 | 25 +++++++++++++++++++++
 kernel/power/swap.c                 |  7 +++---
 mm/page_io.c                        | 30 +++++++++++++------------
 28 files changed, 151 insertions(+), 195 deletions(-)

Comments

Damien Le Moal Jan. 28, 2021, 7:21 a.m. UTC | #1 
On 2021/01/28 16:12, Chaitanya Kulkarni wrote:
> Introduce bio_new() helper and use it in blk-lib.c to allocate and
> initialize various non-optional or semi-optional members of the bio
> along with bio allocation done with bio_alloc(). Here we also calmp the
> max_bvecs for bio with BIO_MAX_PAGES before we pass to bio_alloc().
> 
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
> ---
>  block/blk-lib.c     |  6 +-----
>  include/linux/bio.h | 25 +++++++++++++++++++++++++
>  2 files changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/block/blk-lib.c b/block/blk-lib.c
> index fb486a0bdb58..ec29415f00dd 100644
> --- a/block/blk-lib.c
> +++ b/block/blk-lib.c
> @@ -14,17 +14,13 @@ struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
>  			sector_t sect, unsigned op, unsigned opf,
>  			unsigned int nr_pages, gfp_t gfp)
>  {
> -	struct bio *new = bio_alloc(gfp, nr_pages);
> +	struct bio *new = bio_new(bdev, sect, op, opf, gfp, nr_pages);
>  
>  	if (bio) {
>  		bio_chain(bio, new);
>  		submit_bio(bio);
>  	}
>  
> -	new->bi_iter.bi_sector = sect;
> -	bio_set_dev(new, bdev);
> -	bio_set_op_attrs(new, op, opf);
> -
>  	return new;
>  }
>  
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index c74857cf1252..2a09ba100546 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -826,5 +826,30 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
>  	if (!is_sync_kiocb(kiocb))
>  		bio->bi_opf |= REQ_NOWAIT;
>  }
> +/**
> + * bio_new -	allcate and initialize new bio
> + * @bdev:	blockdev to issue discard for
> + * @sector:	start sector
> + * @op:		REQ_OP_XXX from enum req_opf
> + * @op_flags:	REQ_XXX from enum req_flag_bits
> + * @max_bvecs:	maximum bvec to be allocated for this bio
> + * @gfp_mask:	memory allocation flags (for bio_alloc)
> + *
> + * Description:
> + *    Allocates, initializes common members, and returns a new bio.
> + */
> +static inline struct bio *bio_new(struct block_device *bdev, sector_t sector,
> +				  unsigned int op, unsigned int op_flags,
> +				  unsigned int max_bvecs, gfp_t gfp_mask)
> +{
> +	unsigned nr_bvec = clamp_t(unsigned int, max_bvecs, 0, BIO_MAX_PAGES);
> +	struct bio *bio = bio_alloc(gfp_mask, nr_bvec);

I think that depending on the gfp_mask passed, bio can be NULL. So this should
be checked.

> +
> +	bio_set_dev(bio, bdev);
> +	bio->bi_iter.bi_sector = sector;
> +	bio_set_op_attrs(bio, op, op_flags);

This function is obsolete. Open code this.

> +
> +	return bio;
> +}
>  
>  #endif /* __LINUX_BIO_H */
>
Damien Le Moal Jan. 28, 2021, 7:27 a.m. UTC | #2 
On 2021/01/28 16:21, Damien Le Moal wrote:
> On 2021/01/28 16:12, Chaitanya Kulkarni wrote:
>> Introduce bio_new() helper and use it in blk-lib.c to allocate and
>> initialize various non-optional or semi-optional members of the bio
>> along with bio allocation done with bio_alloc(). Here we also calmp the
>> max_bvecs for bio with BIO_MAX_PAGES before we pass to bio_alloc().
>>
>> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
>> ---
>>  block/blk-lib.c     |  6 +-----
>>  include/linux/bio.h | 25 +++++++++++++++++++++++++
>>  2 files changed, 26 insertions(+), 5 deletions(-)
>>
>> diff --git a/block/blk-lib.c b/block/blk-lib.c
>> index fb486a0bdb58..ec29415f00dd 100644
>> --- a/block/blk-lib.c
>> +++ b/block/blk-lib.c
>> @@ -14,17 +14,13 @@ struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
>>  			sector_t sect, unsigned op, unsigned opf,
>>  			unsigned int nr_pages, gfp_t gfp)
>>  {
>> -	struct bio *new = bio_alloc(gfp, nr_pages);
>> +	struct bio *new = bio_new(bdev, sect, op, opf, gfp, nr_pages);
>>  
>>  	if (bio) {
>>  		bio_chain(bio, new);
>>  		submit_bio(bio);
>>  	}
>>  
>> -	new->bi_iter.bi_sector = sect;
>> -	bio_set_dev(new, bdev);
>> -	bio_set_op_attrs(new, op, opf);
>> -
>>  	return new;
>>  }
>>  
>> diff --git a/include/linux/bio.h b/include/linux/bio.h
>> index c74857cf1252..2a09ba100546 100644
>> --- a/include/linux/bio.h
>> +++ b/include/linux/bio.h
>> @@ -826,5 +826,30 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
>>  	if (!is_sync_kiocb(kiocb))
>>  		bio->bi_opf |= REQ_NOWAIT;
>>  }
>> +/**
>> + * bio_new -	allcate and initialize new bio
>> + * @bdev:	blockdev to issue discard for
>> + * @sector:	start sector
>> + * @op:		REQ_OP_XXX from enum req_opf
>> + * @op_flags:	REQ_XXX from enum req_flag_bits
>> + * @max_bvecs:	maximum bvec to be allocated for this bio
>> + * @gfp_mask:	memory allocation flags (for bio_alloc)
>> + *
>> + * Description:
>> + *    Allocates, initializes common members, and returns a new bio.
>> + */
>> +static inline struct bio *bio_new(struct block_device *bdev, sector_t sector,
>> +				  unsigned int op, unsigned int op_flags,
>> +				  unsigned int max_bvecs, gfp_t gfp_mask)
>> +{
>> +	unsigned nr_bvec = clamp_t(unsigned int, max_bvecs, 0, BIO_MAX_PAGES);
>> +	struct bio *bio = bio_alloc(gfp_mask, nr_bvec);
> 
> I think that depending on the gfp_mask passed, bio can be NULL. So this should
> be checked.
> 
>> +
>> +	bio_set_dev(bio, bdev);
>> +	bio->bi_iter.bi_sector = sector;
>> +	bio_set_op_attrs(bio, op, op_flags);
> 
> This function is obsolete. Open code this.

And that also mean that you could remove one argument to bio_new(): combine op
and op_flags into "unsigned int opf"

> 
>> +
>> +	return bio;
>> +}
>>  
>>  #endif /* __LINUX_BIO_H */
>>
> 
>
Matthew Wilcox Jan. 28, 2021, 4:47 p.m. UTC | #3 
FYI your email is completely unreadable to those not using html.
I can't tell what you wrote and what Damien wrote.

On Thu, Jan 28, 2021 at 08:33:10AM +0000, Chaitanya Kulkarni wrote:
> On 1/27/21 11:21 PM, Damien Le Moal wrote:
> 
> On 2021/01/28 16:12, Chaitanya Kulkarni wrote:
> 
> 
> Introduce bio_new() helper and use it in blk-lib.c to allocate and
> initialize various non-optional or semi-optional members of the bio
> along with bio allocation done with bio_alloc(). Here we also calmp the
> max_bvecs for bio with BIO_MAX_PAGES before we pass to bio_alloc().
> 
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com><mailto:chaitanya.kulkarni@wdc.com>
> ---
>  block/blk-lib.c     |  6 +-----
>  include/linux/bio.h | 25 +++++++++++++++++++++++++
>  2 files changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/block/blk-lib.c b/block/blk-lib.c
> index fb486a0bdb58..ec29415f00dd 100644
> --- a/block/blk-lib.c
> +++ b/block/blk-lib.c
> @@ -14,17 +14,13 @@ struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
>                         sector_t sect, unsigned op, unsigned opf,
>                         unsigned int nr_pages, gfp_t gfp)
>  {
> -       struct bio *new = bio_alloc(gfp, nr_pages);
> +       struct bio *new = bio_new(bdev, sect, op, opf, gfp, nr_pages);
> 
>         if (bio) {
>                 bio_chain(bio, new);
>                 submit_bio(bio);
>         }
> 
> -       new->bi_iter.bi_sector = sect;
> -       bio_set_dev(new, bdev);
> -       bio_set_op_attrs(new, op, opf);
> -
>         return new;
>  }
> 
> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index c74857cf1252..2a09ba100546 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -826,5 +826,30 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
>         if (!is_sync_kiocb(kiocb))
>                 bio->bi_opf |= REQ_NOWAIT;
>  }
> +/**
> + * bio_new -   allcate and initialize new bio
> + * @bdev:      blockdev to issue discard for
> + * @sector:    start sector
> + * @op:                REQ_OP_XXX from enum req_opf
> + * @op_flags:  REQ_XXX from enum req_flag_bits
> + * @max_bvecs: maximum bvec to be allocated for this bio
> + * @gfp_mask:  memory allocation flags (for bio_alloc)
> + *
> + * Description:
> + *    Allocates, initializes common members, and returns a new bio.
> + */
> +static inline struct bio *bio_new(struct block_device *bdev, sector_t sector,
> +                                 unsigned int op, unsigned int op_flags,
> +                                 unsigned int max_bvecs, gfp_t gfp_mask)
> +{
> +       unsigned nr_bvec = clamp_t(unsigned int, max_bvecs, 0, BIO_MAX_PAGES);
> +       struct bio *bio = bio_alloc(gfp_mask, nr_bvec);
> 
> 
> I think that depending on the gfp_mask passed, bio can be NULL. So this should
> be checked.
> 
> 
> true, I'll add that check.
> 
> 
> 
> 
> +
> +       bio_set_dev(bio, bdev);
> +       bio->bi_iter.bi_sector = sector;
> +       bio_set_op_attrs(bio, op, op_flags);
> 
> 
> This function is obsolete. Open code this.
> 
> 
> true, will do.
> 
> 
> 
> 
> +
> +       return bio;
> +}
> 
>  #endif /* __LINUX_BIO_H */
> 
> 
> 
> Thanks for the comments Damien.

> _______________________________________________
> Ocfs2-devel mailing list
> Ocfs2-devel@oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
Darrick J. Wong Jan. 28, 2021, 5:21 p.m. UTC | #4 
On Wed, Jan 27, 2021 at 11:11:26PM -0800, Chaitanya Kulkarni wrote:
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_buf.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index f8400bbd6473..3ff6235e4f94 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -1507,12 +1507,10 @@ xfs_buf_ioapply_map(
>  	atomic_inc(&bp->b_io_remaining);
>  	nr_pages = min(total_nr_pages, BIO_MAX_PAGES);
>  
> -	bio = bio_alloc(GFP_NOIO, nr_pages);
> -	bio_set_dev(bio, bp->b_target->bt_bdev);
> -	bio->bi_iter.bi_sector = sector;
> +	bio = bio_new(bp->b_target->bt_bdev, sector, op, 0, nr_pages,
> +		      GFP_NOIO);
>  	bio->bi_end_io = xfs_buf_bio_end_io;
>  	bio->bi_private = bp;
> -	bio->bi_opf = op;
>  
>  	for (; size && nr_pages; nr_pages--, page_index++) {
>  		int	rbytes, nbytes = PAGE_SIZE - offset;
> -- 
> 2.22.1
>
Pavel Machek Feb. 17, 2021, 10:02 p.m. UTC | #5 
Hi!
> 

> diff --git a/kernel/power/swap.c b/kernel/power/swap.c

> index c73f2e295167..e92e36c053a6 100644

> --- a/kernel/power/swap.c

> +++ b/kernel/power/swap.c

> @@ -271,13 +271,12 @@ static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr,

>  		struct hib_bio_batch *hb)

>  {

>  	struct page *page = virt_to_page(addr);

> +	sector_t sect = page_off * (PAGE_SIZE >> 9);

>  	struct bio *bio;

>  	int error = 0;

>  

> -	bio = bio_alloc(GFP_NOIO | __GFP_HIGH, 1);

> -	bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);

> -	bio_set_dev(bio, hib_resume_bdev);

> -	bio_set_op_attrs(bio, op, op_flags);

> +	bio = bio_new(hib_resume_bdev, sect, op, op_flags, 1,

> +		      GFP_NOIO | __GFP_HIGH);

>  


C function with 6 arguments... dunno. Old version looks comparable or
even more readable...

Best regards,
							Pavel

-- 
http://www.livejournal.com/~pavelmachek
Chaitanya Kulkarni Feb. 18, 2021, 1:28 a.m. UTC | #6 
On 2/17/21 14:03, Pavel Machek wrote:
> Hi!
>> diff --git a/kernel/power/swap.c b/kernel/power/swap.c
>> index c73f2e295167..e92e36c053a6 100644
>> --- a/kernel/power/swap.c
>> +++ b/kernel/power/swap.c
>> @@ -271,13 +271,12 @@ static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr,
>>  		struct hib_bio_batch *hb)
>>  {
>>  	struct page *page = virt_to_page(addr);
>> +	sector_t sect = page_off * (PAGE_SIZE >> 9);
>>  	struct bio *bio;
>>  	int error = 0;
>>  
>> -	bio = bio_alloc(GFP_NOIO | __GFP_HIGH, 1);
>> -	bio->bi_iter.bi_sector = page_off * (PAGE_SIZE >> 9);
>> -	bio_set_dev(bio, hib_resume_bdev);
>> -	bio_set_op_attrs(bio, op, op_flags);
>> +	bio = bio_new(hib_resume_bdev, sect, op, op_flags, 1,
>> +		      GFP_NOIO | __GFP_HIGH);
>>  
> C function with 6 arguments... dunno. Old version looks comparable or
> even more readable...
>
> Best regards,
> 							Pavel
The library functions that are in the kernel tree which are used
in different file-systems and fabrics drivers do take 6 arguments.

Plus what is the point of duplicating code for mandatory
parameters all over the kernel ?