linux-toradex.git/block, branch v2.6.32.15

block: ensure jiffies wrap is handled correctly in blk_rq_timed_out_timer

2010-05-12T21:57:05+00:00

commit a534dbe96e9929c7245924d8252d89048c23d569 upstream.

blk_rq_timed_out_timer() relied on blk_add_timer() never returning a
timer value of zero, but commit 7838c15b8dd18e78a523513749e5b54bda07b0cb
removed the code that bumped this value when it was zero.
Therefore when jiffies is near wrap we could get unlucky & not set the
timeout value correctly.

This patch uses a flag to indicate that the timeout value was set and so
handles jiffies wrap correctly, and it keeps all the logic in one
function so should be easier to maintain in the future.

Signed-off-by: Richard Kennedy 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: Backport of various I/O topology fixes from 2.6.33 and 2.6.34

2010-04-01T22:58:56+00:00

block: Backport of various I/O topology fixes from 2.6.33 and 2.6.34

The stacking code incorrectly scaled up the data offset in some cases
causing misaligned devices to report alignment.  Rewrite the stacking
algorithm to remedy this.  

(Upstream commit 9504e0864b58b4a304820dcf3755f1da80d5e72f)

The top device misalignment flag would not be set if the added bottom
device was already misaligned as opposed to causing a stacking failure.
    
Also massage the reporting so that an error is only returned if adding
the bottom device caused the misalignment.  I.e. don't return an error
if the top is already flagged as misaligned.

(Upstream commit fe0b393f2c0a0d23a9bc9ed7dc51a1ee511098bd)


lcm() was defined to take integer-sized arguments.  The supplied
arguments are multiplied, however, causing us to overflow given
sufficiently large input.  That in turn led to incorrect optimal I/O
size reporting in some cases.  Switch lcm() over to unsigned long
similar to gcd() and move the function from blk-settings.c to lib.

Signed-off-by: Martin K. Petersen 
Reviewed-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

block: bdev_stack_limits wrapper

2010-01-25T18:49:40+00:00

commit 17be8c245054b9c7786545af3ba3ca4e54cd4ad9 upstream.

DM does not want to know about partition offsets.  Add a partition-aware
wrapper that DM can use when stacking block devices.

Signed-off-by: Martin K. Petersen 
Acked-by: Mike Snitzer 
Reviewed-by: Alasdair G Kergon 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

cfq-iosched: limit coop preemption

2009-11-03T19:25:02+00:00

CFQ has an optimization for cooperated applications. if several
io-context have close requests, they will get boost. But the
optimization get abused. Considering thread a, b, which work on one
file. a reads sectors s, s+2, s+4, ...; b reads sectors s+1, s+3, s
+5, ... Both a and b are sequential read, so they can open idle window.
a reads a sector s and goes to idle window and wakeup b. b reads sector
s+1, since in current implementation, cfq_should_preempt() thinks a and
b are cooperators, b will preempt a. b then reads sector s+1 and goes to
idle window and wakeup a. for the same reason, a will preempt b and
reads s+2. a and b will continue the circle. The circle will be very
long, and a and b will occupy whole disk queue. Other applications will
nearly have no chance to run.

Fix this limiting coop preempt until a queue is scheduled normally
again.

Signed-off-by: Shaohua Li 
Acked-by: Jeff Moyer 
Signed-off-by: Jens Axboe

cfq-iosched: fix bad return value cfq_should_preempt()

2009-11-03T19:21:35+00:00

Commit a6151c3a5c8e1ff5a28450bc8d6a99a2a0add0a7 inadvertently reversed
a preempt condition check, potentially causing a performance regression.
Make the meta check correct again.

Signed-off-by: Jens Axboe

block: silently error unsupported empty barriers too

2009-10-24T12:14:31+00:00

With 2.6.32-rc5 in a KVM guest using dm and virtio_blk, we see the
following errors:

  end_request: I/O error, dev vda, sector 0
  end_request: I/O error, dev vda, sector 0

The errors go away if dm stops submitting empty barriers, by reverting:

  commit 52b1fd5a27c625c78373e024bf570af3c9d44a79
  Author: Mikulas Patocka 
    dm: send empty barriers to targets in dm_flush

We should silently error all barriers, even empty barriers, on devices
like virtio_blk which don't support them.

See also:

  https://bugzilla.redhat.com/514901

Signed-off-by: Mark McLoughlin 
Signed-off-by: Mike Snitzer 
Acked-by: Alasdair G Kergon 
Acked-by: Mikulas Patocka 
Cc: Rusty Russell 
Cc: Neil Brown 
Cc: Christoph Hellwig 
Signed-off-by: Jens Axboe

blk-settings: fix function parameter kernel-doc notation

2009-10-12T06:20:47+00:00

Fix kernel-doc notation in blk-settings.c::blk_queue_max_discard_sectors().

Signed-off-by: Randy Dunlap 
Signed-off-by: Jens Axboe

elv_iosched_store(): fix strstrip() misuse

2009-10-09T06:48:08+00:00

elv_iosched_store() ignore the return value of strstrip().  It makes small
inconsistent behavior.

This patch fixes it.

 
 ====================================
 # cd /sys/block/{blockdev}/queue

 case1:
 # echo "anticipatory" > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case2:
 # echo "anticipatory " > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case3:
 # echo " anticipatory" > scheduler
 bash: echo: write error: Invalid argument

 
 ====================================
 # cd /sys/block/{blockdev}/queue

 case1:
 # echo "anticipatory" > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case2:
 # echo "anticipatory " > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case3:
 # echo " anticipatory" > scheduler
 noop [anticipatory] deadline cfq

Cc: Li Zefan 
Cc: Jens Axboe 
Signed-off-by: KOSAKI Motohiro 
Signed-off-by: Jens Axboe

cfq-iosched: avoid probable slice overrun when idling

2009-10-08T06:43:32+00:00

If the average think time is larger than the remaining time slice
for any given queue, don't allow it to idle. A succesful idle also
means that we need to dispatch and complete a request, so if we don't
even have time left for the idle process, we would overrun the slice
in any case.

Signed-off-by: Corrado Zoccolo 
Signed-off-by: Jens Axboe

cfq-iosched: apply bool value where we return 0/1

2009-10-07T18:02:57+00:00

Saves 16 bytes of text, woohoo. But the more important point is
that it makes the code more readable when returning bool for 0/1
cases.

Signed-off-by: Jens Axboe