linux-toradex.git/block/blk-ioc.c, branch v2.6.32.60

block: Fix io_context leak after failure of clone with CLONE_IO

2012-10-07T21:37:22+00:00

commit b69f2292063d2caf37ca9aec7d63ded203701bf3 upstream

With CLONE_IO, parent's io_context->nr_tasks is incremented, but never
decremented whenever copy_process() fails afterwards, which prevents
exit_io_context() from calling IO schedulers exit functions.

Give a task_struct to exit_io_context(), and call exit_io_context() instead of
put_io_context() in copy_process() cleanup path.

Signed-off-by: Louis Rilling 
Signed-off-by: Jens Axboe 
Signed-off-by: Willy Tarreau

block: Fix io_context leak after clone with CLONE_IO

2012-10-07T21:37:22+00:00

commit 61cc74fbb87af6aa551a06a370590c9bc07e29d9 upstream

With CLONE_IO, copy_io() increments both ioc->refcount and ioc->nr_tasks.
However exit_io_context() only decrements ioc->refcount if ioc->nr_tasks
reaches 0.

Always call put_io_context() in exit_io_context().

Signed-off-by: Louis Rilling 
Signed-off-by: Jens Axboe 
Signed-off-by: Willy Tarreau

block: prevent possible io_context->refcount overflow

2009-06-10T21:07:15+00:00

Currently io_context has an atomic_t(32-bit) as refcount.  In the case of
cfq, for each device against whcih a task does I/O, a reference to the
io_context would be taken.  And when there are multiple process sharing
io_contexts(CLONE_IO) would also have a reference to the same io_context.

Theoretically the possible maximum number of processes sharing the same
io_context + the number of disks/cfq_data referring to the same io_context
can overflow the 32-bit counter on a very high-end machine.

Even though it is an improbable case, let us make it atomic_long_t.

Signed-off-by: Nikanth Karthikesan 
Signed-off-by: Andrew Morton 
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

cfq-iosched: add hlist for browsing parallel to the radix tree

2008-02-19T09:04:00+00:00

It's cumbersome to browse a radix tree from start to finish, especially
since we modify keys when a process exits. So add a hlist for the single
purpose of browsing over all known cfq_io_contexts, used for exit,
io prio change, etc.

This fixes http://bugzilla.kernel.org/show_bug.cgi?id=9948

Signed-off-by: Jens Axboe

make blk_ioc_init() static

2008-02-19T09:04:00+00:00

blk_ioc_init() can become static.

Signed-off-by: Adrian Bunk 
Signed-off-by: Jens Axboe

block: kill swap_io_context()

2008-02-01T10:34:49+00:00

It blindly copies everything in the io_context, including the lock.
That doesn't work so well for either lock ordering or lockdep.

There seems zero point in swapping io contexts on a request to request
merge, so the best point of action is to just remove it.

Signed-off-by: Jens Axboe

block: continue ll_rw_blk.c splitup

2008-01-29T20:55:08+00:00

Adds files for barrier handling, rq execution, io context handling,
mapping data to requests, and queue settings.

Signed-off-by: Jens Axboe