linux.git/block, branch v2.6.26-rc2

block: avoid duplicate calls to get_part() in disk stat code

2008-05-07T08:15:46+00:00

get_part() is fairly expensive, as it O(N) loops over partitions
to find the right one. In lots of normal IO paths we end up looking
up the partition twice, to make matters even worse. Change the
stat add code to accept a passed in partition instead.

Signed-off-by: Jens Axboe

cfq-iosched: make io priorities inherit CPU scheduling class as well as nice

2008-05-07T07:51:23+00:00

We currently set all processes to the best-effort scheduling class,
regardless of what CPU scheduling class they belong to. Improve that
so that we correctly track idle and rt scheduling classes as well.

Signed-off-by: Jens Axboe

block: optimize generic_unplug_device()

2008-05-07T07:48:17+00:00

Original patch from Mikulas Patocka 

Mike Anderson was doing an OLTP benchmark on a computer with 48 physical
disks mapped to one logical device via device mapper.

He found that there was a slowdown on request_queue->lock in function
generic_unplug_device. The slowdown is caused by the fact that when some
code calls unplug on the device mapper, device mapper calls unplug on all
physical disks. These unplug calls take the lock, find that the queue is
already unplugged, release the lock and exit.

With the below patch, performance of the benchmark was increased by 18%
(the whole OLTP application, not just block layer microbenchmarks).

So I'm submitting this patch for upstream. I think the patch is correct,
because when more threads call simultaneously plug and unplug, it is
unspecified, if the queue is or isn't plugged (so the patch can't make
this worse). And the caller that plugged the queue should unplug it
anyway. (if it doesn't, there's 3ms timeout).

Signed-off-by: Mikulas Patocka 
Signed-off-by: Jens Axboe

block: get rid of likely/unlikely predictions in merge logic

2008-05-07T07:33:55+00:00

They tend to depend a lot on the workload, so not a clear-cut
likely or unlikely fit.

Signed-off-by: Jens Axboe

cfq-iosched: fix RCU race in the cfq io_context destructor handling

2008-05-07T07:28:57+00:00

put_io_context() drops the RCU read lock before calling into cfq_dtor(),
however we need to hold off freeing there before grabbing and
dereferencing the first object on the list.

So extend the rcu_read_lock() scope to cover the calling of cfq_dtor(),
and optimize cfq_free_io_context() to use a new variant for
call_for_each_cic() that assumes the RCU read lock is already held.

Hit in the wild by Alexey Dobriyan 

Signed-off-by: Jens Axboe

block: adjust tagging function queue bit locking

2008-05-07T07:27:43+00:00

For most initialization purposes, calling blk_queue_init_tags() without
the queue lock held is OK. Only if called for resizing an existing map
must the lock be held. Ditto for tag cleanup, the maps are reference
counted.

So switch the general queue flag setting to the unlocked variant, but
retain the locked variant for resizing.

Signed-off-by: Jens Axboe

block: sysfs store function needs to grab queue_lock and use queue_flag_*()

2008-05-07T07:09:39+00:00

Concurrency isn't a big deal here since we have requests in flight
at this point, but do the locked variant to set a better example.

Signed-off-by: Jens Axboe

Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6

2008-05-02T20:52:35+00:00

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6:
  [SCSI] aic94xx: fix section mismatch
  [SCSI] u14-34f: Fix 32bit only problem
  [SCSI] dpt_i2o: sysfs code
  [SCSI] dpt_i2o: 64 bit support
  [SCSI] dpt_i2o: move from virt_to_bus/bus_to_virt to dma_alloc_coherent
  [SCSI] dpt_i2o: use standard __init / __exit code
  [SCSI] megaraid_sas: fix suspend/resume sections
  [SCSI] aacraid: Add Power Management support
  [SCSI] aacraid: Fix jbod operations scan issues
  [SCSI] aacraid: Fix warning about macro side-effects
  [SCSI] add support for variable length extended commands
  [SCSI] Let scsi_cmnd->cmnd use request->cmd buffer
  [SCSI] bsg: add large command support
  [SCSI] aacraid: Fix down_interruptible() to check the return value correctly
  [SCSI] megaraid_sas; Update the Version and Changelog
  [SCSI] ibmvscsi: Handle non SCSI error status
  [SCSI] bug fix for free list handling
  [SCSI] ipr: Rename ipr's state scsi host attribute to prevent collisions
  [SCSI] megaraid_mbox: fix Dell CERC firmware problem

[SCSI] add support for variable length extended commands

2008-05-02T16:33:25+00:00

Add support for variable-length, extended, and vendor specific
CDBs to scsi-ml. It is now possible for initiators and ULD's
to issue these types of commands. LLDs need not change much.
All they need is to raise the .max_cmd_len to the longest command
they support (see iscsi patch).

- clean-up some code paths that did not expect commands to be
  larger than 16, and change cmd_len members' type to short as
  char is not enough.

Signed-off-by: Boaz Harrosh 
Signed-off-by: Benny Halevy 
Signed-off-by: James Bottomley

[SCSI] bsg: add large command support

2008-05-02T15:17:35+00:00

This enables bsg to handle the request length larger than BLK_MAX_CDB
(mainly for the variable length CDB format).

Signed-off-by: FUJITA Tomonori 
Acked-by: Jens Axboe 
Signed-off-by: James Bottomley