linux-toradex.git/block, branch v2.6.26-rc3

Remove blkdev warning triggered by using md

2008-05-15T02:11:15+00:00

As setting and clearing queue flags now requires that we hold a spinlock
on the queue, and as blk_queue_stack_limits is called without that lock,
get the lock inside blk_queue_stack_limits.

For blk_queue_stack_limits to be able to find the right lock, each md
personality needs to set q->queue_lock to point to the appropriate lock.
Those personalities which didn't previously use a spin_lock, us
q->__queue_lock.  So always initialise that lock when allocated.

With this in place, setting/clearing of the QUEUE_FLAG_PLUGGED bit will no
longer cause warnings as it will be clear that the proper lock is held.

Thanks to Dan Williams for review and fixing the silly bugs.

Signed-off-by: NeilBrown 
Cc: Dan Williams 
Cc: Jens Axboe 
Cc: Alistair John Strachan 
Cc: Nick Piggin 
Cc: "Rafael J. Wysocki" 
Cc: Jacek Luczak 
Cc: Prakash Punnoor 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

block: do_mounts - accept root=

2008-05-14T17:37:57+00:00

Some devices, like md, may create partitions only at first access,
so allow root= to be set to a valid non-existant partition of an
existing disk. This applies only to non-initramfs root mounting.

This fixes a regression from 2.6.24 which did allow this to happen and
broke some users machines :(

Acked-by: Neil Brown 
Tested-by: Joao Luis Meloni Assirati 
Cc: stable 
Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Fix misuses of bdevname()

2008-05-13T15:02:26+00:00

bdevname() fills the buffer that it is given as a parameter, so calling
strcpy() or snprintf() on the returned value is redundant (and probably not
guaranteed to work - I don't think strcpy and snprintf support overlapping
buffers.)

Signed-off-by: Jean Delvare 
Cc: Stephen Tweedie 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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