linux-toradex.git/drivers/block/null_blk.c, branch v4.2.8

null_blk: fix use-after-free problem

2015-07-22T19:30:20+00:00

end_cmd finishes request associated with nullb_cmd struct, so we
should save pointer to request_queue in a local variable before
calling end_cmd.

The problem was causes general protection fault with slab poisoning
enabled.

Fixes: 8b70f45e2eb2 ("null_blk: restart request processing on completion handler")
Tested-by: Akinobu Mita 
Signed-off-by: Mike Krinkin 
Signed-off-by: Jens Axboe

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-07-01T17:49:25+00:00

Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...

null_blk: restart request processing on completion handler

2015-06-02T02:09:05+00:00

When irqmode=2 (IRQ completion handler is timer) and queue_mode=1
(Block interface to use is rq), the completion handler should restart
request handling for any pending requests on a queue because request
processing stops when the number of commands are queued more than
hw_queue_depth (null_rq_prep_fn returns BLKPREP_DEFER).

Without this change, the following command cannot finish.

	# modprobe null_blk irqmode=2 queue_mode=1 hw_queue_depth=1
	# fio --name=t --rw=read --size=1g --direct=1 \
	  --ioengine=libaio --iodepth=64 --filename=/dev/nullb0

Signed-off-by: Akinobu Mita 
Cc: Jens Axboe 
Signed-off-by: Jens Axboe

null_blk: prevent timer handler running on a different CPU where started

2015-06-02T02:09:03+00:00

When irqmode=2 (IRQ completion handler is timer), timer handler should
be called on the same CPU where the timer has been started.

Since completion_queues are per-cpu and the completion handler only
touches completion_queue for local CPU, we need to prevent the handler
from running on a different CPU where the timer has been started.
Otherwise, the IO cannot be completed until another completion handler
is executed on that CPU.

Signed-off-by: Akinobu Mita 
Cc: Jens Axboe 
Signed-off-by: Jens Axboe

kernel/params: constify struct kernel_param_ops uses

2015-05-28T02:02:10+00:00

Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.

In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.

Test compiled on x86_64 against:

	* allnoconfig
	* allmodconfig
	* allyesconfig

@ const_found @
identifier ops;
@@

const struct kernel_param_ops ops = {
};

@ const_not_found depends on !const_found @
identifier ops;
@@

-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};

Generated-by: Coccinelle SmPL
Cc: Rusty Russell 
Cc: Junio C Hamano 
Cc: Andrew Morton 
Cc: Kees Cook 
Cc: Tejun Heo 
Cc: Ingo Molnar 
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez 
Signed-off-by: Rusty Russell

null_blk: suppress invalid partition info

2015-01-16T23:02:24+00:00

null_blk is partitionable, but it doesn't store any of the info. When
it is loaded, you would normally see:

[1226739.343608]  nullb0: unknown partition table
[1226739.343746]  nullb1: unknown partition table

which can confuse some people. Add the appropriate gendisk flag
to suppress this info.

Signed-off-by: Jens Axboe

block: fix checking return value of blk_mq_init_queue

2015-01-02T17:32:02+00:00

Check IS_ERR_OR_NULL(return value) instead of just return value.

Signed-off-by: Ming Lei 

Reduced to IS_ERR() by me, we never return NULL.
Signed-off-by: Jens Axboe

null_blk: boundary check queue_mode and irqmode

2014-11-26T21:45:48+00:00

When either queue_mode or irq_mode parameter is set outside its
boundaries, the driver will not complete requests. This stalls driver
initialization when partitions are probed. Fix by setting out of bound
values to the parameters default.

Signed-off-by: Matias Bjørling 

Updated by me to have the parse+check in just one function.

Signed-off-by: Jens Axboe

Merge branch 'master' into for-3.19/drivers

2014-11-19T02:43:46+00:00

blk-mq: add a 'list' parameter to ->queue_rq()

2014-10-29T17:14:52+00:00

Since we have the notion of a 'last' request in a chain, we can use
this to have the hardware optimize the issuing of requests. Add
a list_head parameter to queue_rq that the driver can use to
temporarily store hw commands for issue when 'last' is true. If we
are doing a chain of requests, pass in a NULL list for the first
request to force issue of that immediately, then batch the remainder
for deferred issue until the last request has been sent.

Instead of adding yet another argument to the hot ->queue_rq path,
encapsulate the passed arguments in a blk_mq_queue_data structure.
This is passed as a constant, and has been tested as faster than
passing 4 (or even 3) args through ->queue_rq. Update drivers for
the new ->queue_rq() prototype. There are no functional changes
in this patch for drivers - if they don't use the passed in list,
then they will just queue requests individually like before.

Signed-off-by: Jens Axboe