linux-toradex.git/include/linux/bio.h, branch v2.6.31.7

block: Create bip slabs with embedded integrity vectors

2009-07-01T08:56:25+00:00

This patch restores stacking ability to the block layer integrity
infrastructure by creating a set of dedicated bip slabs.  Each bip slab
has an embedded bio_vec array at the end.  This cuts down on memory
allocations and also simplifies the code compared to the original bvec
version.  Only the largest bip slab is backed by a mempool.  The pool is
contained in the bio_set so stacking drivers can ensure forward
progress.

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

block: Add bio_list_peek()

2009-06-15T06:47:21+00:00

Introduce bio_list_peek(), to obtain a pointer to the first bio on the bio_list
without actually removing it from the list. This is needed when you want to
serialize based on the list being empty or not.

Signed-off-by: Geert Uytterhoeven 
Acked-by: Jens Axboe 
Signed-off-by: Benjamin Herrenschmidt

block: Use accessor functions for queue limits

2009-05-22T21:22:54+00:00

Convert all external users of queue limits to using wrapper functions
instead of poking the request queue variables directly.

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

block: drop request->hard_* and *nr_sectors

2009-05-11T07:50:54+00:00

struct request has had a few different ways to represent some
properties of a request.  ->hard_* represent block layer's view of the
request progress (completion cursor) and the ones without the prefix
are supposed to represent the issue cursor and allowed to be updated
as necessary by the low level drivers.  The thing is that as block
layer supports partial completion, the two cursors really aren't
necessary and only cause confusion.  In addition, manual management of
request detail from low level drivers is cumbersome and error-prone at
the very least.

Another interesting duplicate fields are rq->[hard_]nr_sectors and
rq->{hard_cur|current}_nr_sectors against rq->data_len and
rq->bio->bi_size.  This is more convoluted than the hard_ case.

rq->[hard_]nr_sectors are initialized for requests with bio but
blk_rq_bytes() uses it only for !pc requests.  rq->data_len is
initialized for all request but blk_rq_bytes() uses it only for pc
requests.  This causes good amount of confusion throughout block layer
and its drivers and determining the request length has been a bit of
black magic which may or may not work depending on circumstances and
what the specific LLD is actually doing.

rq->{hard_cur|current}_nr_sectors represent the number of sectors in
the contiguous data area at the front.  This is mainly used by drivers
which transfers data by walking request segment-by-segment.  This
value always equals rq->bio->bi_size >> 9.  However, data length for
pc requests may not be multiple of 512 bytes and using this field
becomes a bit confusing.

In general, having multiple fields to represent the same property
leads only to confusion and subtle bugs.  With recent block low level
driver cleanups, no driver is accessing or manipulating these
duplicate fields directly.  Drop all the duplicates.  Now rq->sector
means the current sector, rq->data_len the current total length and
rq->bio->bi_size the current segment length.  Everything else is
defined in terms of these three and available only through accessors.

* blk_recalc_rq_sectors() is collapsed into blk_update_request() and
  now handles pc and fs requests equally other than rq->sector update.
  This means that now pc requests can use partial completion too (no
  in-kernel user yet tho).

* bio_cur_sectors() is replaced with bio_cur_bytes() as block layer
  now uses byte count as the primary data length.

* blk_rq_pos() is now guranteed to be always correct.  In-block users
  converted.

* blk_rq_bytes() is now guaranteed to be always valid as is
  blk_rq_sectors().  In-block users converted.

* blk_rq_sectors() is now guaranteed to equal blk_rq_bytes() >> 9.
  More convenient one is used.

* blk_rq_bytes() and blk_rq_cur_bytes() are now inlined and take const
  pointer to request.

[ Impact: API cleanup, single way to represent one property of a request ]

Signed-off-by: Tejun Heo 
Cc: Boaz Harrosh 
Signed-off-by: Jens Axboe

loop: use BIO list management functions

2009-04-28T05:37:28+00:00

Now that the bio list management stuff is generic, convert loop to use
bio lists instead of its own private bio list implementation.

Cc:  Jens Axboe 
Cc: Christoph Hellwig 
Signed-off-by: Akinobu Mita 
Signed-off-by: Jens Axboe

bio: fix bio_kmalloc()

2009-04-22T06:35:10+00:00

Impact: fix bio_kmalloc() and its destruction path

bio_kmalloc() was broken in two ways.

* bvec_alloc_bs() first allocates bvec using kmalloc() and then
  ignores it and allocates again like non-kmalloc bvecs.

* bio_kmalloc_destructor() didn't check for and free bio integrity
  data.

This patch fixes the above problems.  kmalloc patch is separated out
from bio_alloc_bioset() and allocates the requested number of bvecs as
inline bvecs.

* bio_alloc_bioset() no longer takes NULL @bs.  None other than
  bio_kmalloc() used it and outside users can't know how it was
  allocated anyway.

* Define and use BIO_POOL_NONE so that pool index check in
  bvec_free_bs() triggers if inline or kmalloc allocated bvec gets
  there.

* Relocate destructors on top of each allocation function so that how
  they're used is more clear.

Jens Axboe suggested allocating bvecs inline.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: move bio list helpers into bio.h

2009-04-15T06:28:09+00:00

It's used by DM and MD and generally useful, so move the bio list
helpers into bio.h.

Signed-off-by: Christoph Hellwig 
Acked-by: Alasdair G Kergon 
Signed-off-by: Jens Axboe

block: Add flag for telling the IO schedulers NOT to anticipate more IO

2009-04-06T15:04:54+00:00

By default, CFQ will anticipate more IO from a given io context if the
previously completed IO was sync. This used to be fine, since the only
sync IO was reads and O_DIRECT writes. But with more "normal" sync writes
being used now, we don't want to anticipate for those.

Add a bio/request flag that informs the IO scheduler that this is a sync
request that we should not idle for. Introduce WRITE_ODIRECT specifically
for O_DIRECT writes, and make sure that the other sync writes set this
flag.

Signed-off-by: Jens Axboe 
Signed-off-by: Linus Torvalds

block: add private bio_set for bio integrity allocations

2009-03-24T11:35:17+00:00

The integrity bio allocation needs its own bio_set to avoid violating
the mempool allocation rules and risking deadlocks.

Signed-off-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

block: Add gfp_mask parameter to bio_integrity_clone()

2009-03-14T20:06:51+00:00

Stricter gfp_mask might be required for clone allocation.
For example, request-based dm may clone bio in interrupt context
so it has to use GFP_ATOMIC.

Signed-off-by: Kiyoshi Ueda 
Signed-off-by: Jun'ichi Nomura 
Acked-by: Martin K. Petersen 
Cc: Alasdair G Kergon 
Signed-off-by: Jens Axboe