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* [PATCH 00/27] block: cleanup direct access on .bi_vcnt & .bi_io_vec
@ 2016-04-05 11:56 Ming Lei
  2016-04-05 11:56 ` [PATCH 09/27] target: use bio_is_full() Ming Lei
  0 siblings, 1 reply; 4+ messages in thread
From: Ming Lei @ 2016-04-05 11:56 UTC (permalink / raw)
  To: Jens Axboe, linux-kernel
  Cc: linux-block, Christoph Hellwig, Boaz Harrosh, Ming Lei, Al Viro,
	Andreas Dilger, Andrew Morton, open list:STAGING SUBSYSTEM,
	open list:DEVICE-MAPPER LVM, open list:DRBD DRIVER, Frank Zago,
	Greg Kroah-Hartman, Hannes Reinecke, James Simmons, Jan Kara,
	Jarod Wilson, Jiri Kosina, Joe Perches, John L. Hammond,
	Julia Lawall, Keith Busch, Kent Overstreet, linux-bcache

Hi Guys,

It is always not a good practice to access bio->bi_vcnt and
bio->bi_io_vec from drivers directly. Also this kind of direct
access will cause trouble when converting to multipage bvecs.

The 1st patch introduces the following 4 bio helpers which can be
used inside drivers for avoiding direct access to .bi_vcnt and .bi_io_vec.

	bio_pages()
	bio_is_full()
	bio_get_base_vec()
	bio_set_vec_table()

Both bio_pages() and bio_is_full() can be easy to convert to
multipage bvecs.

For bio_get_base_vec() and bio_set_vec_table(), they are often used
during initializing a new bio or in case of single bvec bio. With the
two new helpers, it becomes quite easy to audit access to .bi_io_vec
and .bi_vcnt.

Most of the other patches use the 4 helpers to clean up most of direct
access to .bi_vcnt and .bi_io_vec from drivers, except for MD and btrfs,
which two subsystems will be done in the future. 

Also bio_add_page() is used in floppy, dm-crypt and fs/logfs to
avoiding direct access to .bi_vcnt & .bi_io_vec.

Thanks,
Ming

Ming Lei (27):
  block: bio: introduce 4 helpers for cleanup
  block: drbd: use bio_get_base_vec() to retrieve the 1st bvec
  block: drbd: remove impossible failure handling
  block: loop: use bio_get_base_vec() to retrive bvec table
  block: pktcdvd: use bio_get_base_vec() to retrive bvec table
  block: floppy: use bio_set_vec_table()
  block: floppy: use bio_add_page()
  staging: lustre: avoid to use bio->bi_vcnt directly
  target: use bio_is_full()
  bcache: debug: avoid to access .bi_io_vec directly
  bcache: io.c: use bio_set_vec_table
  bcache: journal.c: use bio_set_vec_table()
  bcache: movinggc: use bio_set_vec_table()
  bcache: writeback: use bio_set_vec_table()
  bcache: super: use bio_set_vec_table()
  bcache: super: use bio_get_base_vec
  dm: crypt: use bio_add_page()
  dm: dm-io.c: use bio_get_base_vec()
  dm: dm.c: replace 'bio->bi_vcnt == 1' with !bio_multiple_segments
  dm: dm-bufio.c: use bio_set_vec_table()
  fs: logfs: use bio_set_vec_table()
  fs: logfs: convert to bio_add_page() in sync_request()
  fs: logfs: use bio_add_page() in __bdev_writeseg()
  fs: logfs: use bio_add_page() in do_erase()
  fs: logfs: remove unnecesary check
  kernel/power/swap.c: use bio_get_base_vec()
  mm: page_io.c: use bio_get_base_vec()

 drivers/block/drbd/drbd_bitmap.c            |   4 +-
 drivers/block/drbd/drbd_receiver.c          |  14 +---
 drivers/block/floppy.c                      |   9 +--
 drivers/block/loop.c                        |   5 +-
 drivers/block/pktcdvd.c                     |   3 +-
 drivers/md/bcache/debug.c                   |  11 ++-
 drivers/md/bcache/io.c                      |   3 +-
 drivers/md/bcache/journal.c                 |   3 +-
 drivers/md/bcache/movinggc.c                |   6 +-
 drivers/md/bcache/super.c                   |  28 +++++---
 drivers/md/bcache/writeback.c               |   4 +-
 drivers/md/dm-bufio.c                       |   3 +-
 drivers/md/dm-crypt.c                       |   8 +--
 drivers/md/dm-io.c                          |   7 +-
 drivers/md/dm.c                             |   3 +-
 drivers/staging/lustre/lustre/llite/lloop.c |   9 +--
 drivers/target/target_core_pscsi.c          |   2 +-
 fs/logfs/dev_bdev.c                         | 107 +++++++++++-----------------
 include/linux/bio.h                         |  28 ++++++++
 kernel/power/swap.c                         |  10 ++-
 mm/page_io.c                                |  18 ++++-
 21 files changed, 156 insertions(+), 129 deletions(-)

-- 
1.9.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH 09/27] target: use bio_is_full()
  2016-04-05 11:56 [PATCH 00/27] block: cleanup direct access on .bi_vcnt & .bi_io_vec Ming Lei
@ 2016-04-05 11:56 ` Ming Lei
  2016-04-05 13:02   ` Christoph Hellwig
  0 siblings, 1 reply; 4+ messages in thread
From: Ming Lei @ 2016-04-05 11:56 UTC (permalink / raw)
  To: Jens Axboe, linux-kernel
  Cc: linux-block, Christoph Hellwig, Boaz Harrosh, Ming Lei,
	Nicholas A. Bellinger, open list:TARGET SUBSYSTEM,
	open list:TARGET SUBSYSTEM

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 drivers/target/target_core_pscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index de18790..24906c3 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -951,7 +951,7 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 			pr_debug("PSCSI: bio->bi_vcnt: %d nr_vecs: %d\n",
 				bio->bi_vcnt, nr_vecs);
 
-			if (bio->bi_vcnt > nr_vecs) {
+			if (bio_is_full(bio)) {
 				pr_debug("PSCSI: Reached bio->bi_vcnt max:"
 					" %d i: %d bio: %p, allocating another"
 					" bio\n", bio->bi_vcnt, i, bio);
-- 
1.9.1

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH 09/27] target: use bio_is_full()
  2016-04-05 11:56 ` [PATCH 09/27] target: use bio_is_full() Ming Lei
@ 2016-04-05 13:02   ` Christoph Hellwig
  2016-04-07  4:07     ` Ming Lei
  0 siblings, 1 reply; 4+ messages in thread
From: Christoph Hellwig @ 2016-04-05 13:02 UTC (permalink / raw)
  To: Ming Lei
  Cc: Jens Axboe, linux-kernel, linux-block, Christoph Hellwig,
	Boaz Harrosh, Nicholas A. Bellinger, open list:TARGET SUBSYSTEM,
	open list:TARGET SUBSYSTEM

On Tue, Apr 05, 2016 at 07:56:54PM +0800, Ming Lei wrote:
> +++ b/drivers/target/target_core_pscsi.c
> @@ -951,7 +951,7 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
>  			pr_debug("PSCSI: bio->bi_vcnt: %d nr_vecs: %d\n",
>  				bio->bi_vcnt, nr_vecs);
>  
> -			if (bio->bi_vcnt > nr_vecs) {
> +			if (bio_is_full(bio)) {
>  				pr_debug("PSCSI: Reached bio->bi_vcnt max:"
>  					" %d i: %d bio: %p, allocating another"
>  					" bio\n", bio->bi_vcnt, i, bio);

This check should be removed entirely - bio_add_pc_page takes care of
it.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH 09/27] target: use bio_is_full()
  2016-04-05 13:02   ` Christoph Hellwig
@ 2016-04-07  4:07     ` Ming Lei
  0 siblings, 0 replies; 4+ messages in thread
From: Ming Lei @ 2016-04-07  4:07 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Jens Axboe, Linux Kernel Mailing List, linux-block, Boaz Harrosh,
	Nicholas A. Bellinger, open list:TARGET SUBSYSTEM,
	open list:TARGET SUBSYSTEM

On Tue, Apr 5, 2016 at 9:02 PM, Christoph Hellwig <hch@infradead.org> wrote:
> On Tue, Apr 05, 2016 at 07:56:54PM +0800, Ming Lei wrote:
>> +++ b/drivers/target/target_core_pscsi.c
>> @@ -951,7 +951,7 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
>>                       pr_debug("PSCSI: bio->bi_vcnt: %d nr_vecs: %d\n",
>>                               bio->bi_vcnt, nr_vecs);
>>
>> -                     if (bio->bi_vcnt > nr_vecs) {
>> +                     if (bio_is_full(bio)) {
>>                               pr_debug("PSCSI: Reached bio->bi_vcnt max:"
>>                                       " %d i: %d bio: %p, allocating another"
>>                                       " bio\n", bio->bi_vcnt, i, bio);
>
> This check should be removed entirely - bio_add_pc_page takes care of
> it.

OK.


-- 
Ming Lei

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2016-04-07  4:07 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2016-04-05 11:56 [PATCH 00/27] block: cleanup direct access on .bi_vcnt & .bi_io_vec Ming Lei
2016-04-05 11:56 ` [PATCH 09/27] target: use bio_is_full() Ming Lei
2016-04-05 13:02   ` Christoph Hellwig
2016-04-07  4:07     ` Ming Lei

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