linux-stable.git/include/linux/blk_types.h, branch v3.7.3

block: Implement support for WRITE SAME

2012-09-20T12:31:45+00:00

The WRITE SAME command supported on some SCSI devices allows the same
block to be efficiently replicated throughout a block range. Only a
single logical block is transferred from the host and the storage device
writes the same data to all blocks described by the I/O.

This patch implements support for WRITE SAME in the block layer. The
blkdev_issue_write_same() function can be used by filesystems and block
drivers to replicate a buffer across a block range. This can be used to
efficiently initialize software RAID devices, etc.

Signed-off-by: Martin K. Petersen 
Acked-by: Mike Snitzer 
Signed-off-by: Jens Axboe

block: Clean up special command handling logic

2012-09-20T12:31:38+00:00

Remove special-casing of non-rw fs style requests (discard). The nomerge
flags are consolidated in blk_types.h, and rq_mergeable() and
bio_mergeable() have been modified to use them.

bio_is_rw() is used in place of bio_has_data() a few places. This is
done to to distinguish true reads and writes from other fs type requests
that carry a payload (e.g. write same).

Signed-off-by: Martin K. Petersen 
Acked-by: Mike Snitzer 
Signed-off-by: Jens Axboe

block: Kill bi_destructor

2012-09-09T08:35:39+00:00

Now that we've got generic code for freeing bios allocated from bio
pools, this isn't needed anymore.

This patch also makes bio_free() static, since without bi_destructor
there should be no need for it to be called anywhere else.

bio_free() is now only called from bio_put, so we can refactor those a
bit - move some code from bio_put() to bio_free() and kill the redundant
bio->bi_next = NULL.

v5: Switch to BIO_KMALLOC_POOL ((void *)~0), per Boaz
v6: BIO_KMALLOC_POOL now NULL, drop bio_free's EXPORT_SYMBOL
v7: No #define BIO_KMALLOC_POOL anymore

Signed-off-by: Kent Overstreet 
CC: Jens Axboe 
Signed-off-by: Jens Axboe

block: Add bio_reset()

2012-09-09T08:35:39+00:00

Reusing bios is something that's been highly frowned upon in the past,
but driver code keeps doing it anyways. If it's going to happen anyways,
we should provide a generic method.

This'll help with getting rid of bi_destructor - drivers/block/pktcdvd.c
was open coding it, by doing a bio_init() and resetting bi_destructor.

This required reordering struct bio, but the block layer is not yet
nearly fast enough for any cacheline effects to matter here.

v5: Add a define BIO_RESET_BITS, to be very explicit about what parts of
bio->bi_flags are saved.
v6: Further commenting verbosity, per Tejun
v9: Add a function comment

Signed-off-by: Kent Overstreet 
CC: Jens Axboe 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: Generalized bio pool freeing

2012-09-09T08:35:38+00:00

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 
CC: Jens Axboe 
CC: NeilBrown 
CC: Alasdair Kergon 
CC: Nicholas Bellinger 
CC: Lars Ellenberg 
Acked-by: Tejun Heo 
Acked-by: Nicholas Bellinger 
Signed-off-by: Jens Axboe

mm: add get_kernel_page[s] for pinning of kernel addresses for I/O

2012-08-01T01:42:47+00:00

This patch adds two new APIs get_kernel_pages() and get_kernel_page() that
may be used to pin a vector of kernel addresses for IO.  The initial user
is expected to be NFS for allowing pages to be written to swap using
aops->direct_IO().  Strictly speaking, swap-over-NFS only needs to pin one
page for IO but it makes sense to express the API in terms of a vector and
add a helper for pinning single pages.

Signed-off-by: Mel Gorman 
Reviewed-by: Rik van Riel 
Cc: Christoph Hellwig 
Cc: David S. Miller 
Cc: Eric B Munson 
Cc: Eric Paris 
Cc: James Morris 
Cc: Mel Gorman 
Cc: Mike Christie 
Cc: Neil Brown 
Cc: Peter Zijlstra 
Cc: Sebastian Andrzej Siewior 
Cc: Trond Myklebust 
Cc: Xiaotian Feng 
Cc: Mark Salter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

block: implement bio_associate_current()

2012-03-06T20:27:24+00:00

IO scheduling and cgroup are tied to the issuing task via io_context
and cgroup of %current.  Unfortunately, there are cases where IOs need
to be routed via a different task which makes scheduling and cgroup
limit enforcement applied completely incorrectly.

For example, all bios delayed by blk-throttle end up being issued by a
delayed work item and get assigned the io_context of the worker task
which happens to serve the work item and dumped to the default block
cgroup.  This is double confusing as bios which aren't delayed end up
in the correct cgroup and makes using blk-throttle and cfq propio
together impossible.

Any code which punts IO issuing to another task is affected which is
getting more and more common (e.g. btrfs).  As both io_context and
cgroup are firmly tied to task including userland visible APIs to
manipulate them, it makes a lot of sense to match up tasks to bios.

This patch implements bio_associate_current() which associates the
specified bio with %current.  The bio will record the associated ioc
and blkcg at that point and block layer will use the recorded ones
regardless of which task actually ends up issuing the bio.  bio
release puts the associated ioc and blkcg.

It grabs and remembers ioc and blkcg instead of the task itself
because task may already be dead by the time the bio is issued making
ioc and blkcg inaccessible and those are all block layer cares about.

elevator_set_req_fn() is updated such that the bio elvdata is being
allocated for is available to the elevator.

This doesn't update block cgroup policies yet.  Further patches will
implement the support.

-v2: #ifdef CONFIG_BLK_CGROUP added around bio->bi_ioc dereference in
     rq_ioc() to fix build breakage.

Signed-off-by: Tejun Heo 
Cc: Vivek Goyal 
Cc: Kent Overstreet 
Signed-off-by: Jens Axboe

block: Remove the control of complete cpu from bio.

2011-10-24T14:11:30+00:00

bio originally has the functionality to set the complete cpu, but
it is broken.

Chirstoph said that "This code is unused, and from the all the
discussions lately pretty obviously broken.  The only thing keeping
it serves is creating more confusion and possibly more bugs."

And Jens replied with "We can kill bio_set_completion_cpu(). I'm fine
with leaving cpu control to the request based drivers, they are the
only ones that can toggle the setting anyway".

So this patch tries to remove all the work of controling complete cpu
from a bio.

Cc: Shaohua Li 
Cc: Christoph Hellwig 
Signed-off-by: Tao Ma 
Signed-off-by: Jens Axboe

block: separate priority boosting from REQ_META

2011-08-23T12:50:29+00:00

Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.

All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Namhyung Kim 
Signed-off-by: Jens Axboe

Move some REQ flags to the common bio/request area

2011-08-11T08:36:03+00:00

REQ_SECURE, REQ_FLUSH and REQ_FUA may all be set on a bio as well as
on a request, so relocate them to the shared part of the enum.

Signed-off-by: Matthew Wilcox 
Signed-off-by: Namhyung Kim 
Reviewed-by: Jeff Moyer 
Signed-off-by: Jens Axboe