linux-toradex.git/block/elevator.c, branch v2.6.36-rc5

block: add function call to switch the IO scheduler from a driver

2010-08-23T11:52:19+00:00

Currently drivers must do an elevator_exit() + elevator_init()
to switch IO schedulers. There are a few problems with this:

- Since commit 1abec4fdbb142e3ccb6ce99832fae42129134a96,
  elevator_init() requires a zeroed out q->elevator
  pointer. The two existing in-kernel users don't do that.

- It will only work at initialization time, since using the
  above two-staged construct does not properly quisce the queue.

So add elevator_change() which takes care of this, and convert
the elv_iosched_store() sysfs interface to use this helper as well.

Reported-by: Peter Oberparleiter 
Reported-by: Kevin Vigor 
Signed-off-by: Jens Axboe

block: add secure discard

2010-08-12T15:43:30+00:00

Secure discard is the same as discard except that all copies of the
discarded sectors (perhaps created by garbage collection) must also be
erased.

Signed-off-by: Adrian Hunter 
Acked-by: Jens Axboe 
Cc: Kyungmin Park 
Cc: Madhusudhan Chikkature 
Cc: Christoph Hellwig 
Cc: Ben Gardiner 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

block: unify flags for struct bio and struct request

2010-08-07T16:20:39+00:00

Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver.  There were two flags in the bio that were
missing in the requests:  BIO_RW_UNPLUG and BIO_RW_AHEAD.  Also I've
renamed two request flags that had a superflous RW in them.

Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: remove wrappers for request type/flags

2010-08-07T16:17:56+00:00

Remove all the trivial wrappers for the cmd_type and cmd_flags fields in
struct requests.  This allows much easier grepping for different request
types instead of unwinding through macros.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: make blk_init_free_list and elevator_init idempotent

2010-06-04T11:47:06+00:00

blk_init_allocated_queue_node may fail and the caller _could_ retry.
Accommodate the unlikely event that blk_init_allocated_queue_node is
called on an already initialized (possibly partially) request_queue.

Signed-off-by: Mike Snitzer 
Signed-off-by: Jens Axboe

block: Adjust elv_iosched_show to return "none" for bio-based DM

2010-05-24T07:07:32+00:00

Bio-based DM doesn't use an elevator (queue is !blk_queue_stackable()).

Longer-term DM will not allocate an elevator for bio-based DM.  But even
then there will be small potential for an elevator to be allocated for
a request-based DM table only to have a bio-based table be loaded in the
end.

Displaying "none" for bio-based DM will help avoid user confusion.

Signed-off-by: Mike Snitzer 
Signed-off-by: Jens Axboe

block: allow initialization of previously allocated request_queue

2010-05-11T06:57:42+00:00

blk_init_queue() allocates the request_queue structure and then
initializes it as needed (request_fn, elevator, etc).

Split initialization out to blk_init_allocated_queue_node.
Introduce blk_init_allocated_queue wrapper function to model existing
blk_init_queue and blk_init_queue_node interfaces.

Export elv_register_queue to allow a newly added elevator to be
registered with sysfs.  Export elv_unregister_queue for symmetry.

These changes allow DM to initialize a device's request_queue with more
precision.  In particular, DM no longer unconditionally initializes a
full request_queue (elevator et al).  It only does so for a
request-based DM device.

Signed-off-by: Mike Snitzer 
Signed-off-by: Jens Axboe

blkio: Add io_merged stat

2010-04-09T06:36:07+00:00

This includes both the number of bios merged into requests belonging to this
cgroup as well as the number of requests merged together.
In the past, we've observed different merging behavior across upstream kernels,
some by design some actual bugs. This stat helps a lot in debugging such
problems when applications report decreased throughput with a new kernel
version.

This needed adding an extra elevator function to capture bios being merged as I
did not want to pollute elevator code with blkiocg knowledge and hence needed
the accounting invocation to come from CFQ.

Signed-off-by: Divyesh Shah
Signed-off-by: Jens Axboe

Block: Fix block/elevator.c elevator_get() off-by-one error

2010-04-02T06:41:14+00:00

elevator_get() not check the name length, if the name length > sizeof(elv),
elv will miss the '\0'. And elv buffer will be replace "-iosched" as something
like aaaaaaaaa, then call request_module() can load an not trust module.

Signed-off-by: Zhitong Wang 
Signed-off-by: Jens Axboe

Driver core: Constify struct sysfs_ops in struct kobj_type

2010-03-08T01:04:49+00:00

Constify struct sysfs_ops.

This is part of the ops structure constification
effort started by Arjan van de Ven et al.

Benefits of this constification:

 * prevents modification of data that is shared
   (referenced) by many other structure instances
   at runtime

 * detects/prevents accidental (but not intentional)
   modification attempts on archs that enforce
   read-only kernel data at runtime

 * potentially better optimized code as the compiler
   can assume that the const data cannot be changed

 * the compiler/linker move const data into .rodata
   and therefore exclude them from false sharing

Signed-off-by: Emese Revfy 
Acked-by: David Teigland 
Acked-by: Matt Domsch 
Acked-by: Maciej Sosnowski 
Acked-by: Hans J. Koch 
Acked-by: Pekka Enberg 
Acked-by: Jens Axboe 
Acked-by: Stephen Hemminger 
Signed-off-by: Greg Kroah-Hartman