linux.git/block/elevator.c, branch v2.6.17

[PATCH] elevator switching race

2006-06-08T22:14:23+00:00

There's a race between shutting down one io scheduler and firing up the
next, in which a new io could enter and cause the io scheduler to be
invoked with bad or NULL data.

To fix this, we need to maintain the queue lock for a bit longer.
Unfortunately we cannot do that, since the elevator init requires to be
run without the lock held.  This isn't easily fixable, without also
changing the mempool API.  So split the initialization into two parts,
and alloc-init operation and an attach operation.  Then we can
preallocate the io scheduler and related structures, and run the attach
inside the lock after we detach the old one.

This patch has survived 30 minutes of 1 second io scheduler switching
with a very busy io load.

Signed-off-by: Jens Axboe 
Signed-off-by: Linus Torvalds

[BLOCK] limit request_fn recursion

2006-05-11T19:38:59+00:00

Don't recurse back into the driver even if the unplug threshold is met,
when the driver asks for a requeue. This is both silly from a logical
point of view (requeues typically happen due to driver/hardware
shortage), and also dangerous since we could hit an endless request_fn
-> requeue -> unplug -> request_fn loop and crash on stack overrun.

Also limit blk_run_queue() to one level of recursion, similar to how
blk_start_queue() works.

This patch fixed a real problem with SLES10 and lpfc, and it could hit
any SCSI lld that returns non-zero from it's ->queuecommand() handler.

Signed-off-by: Jens Axboe 
Signed-off-by: Linus Torvalds

[PATCH] block/elevator.c: remove unused exports

2006-04-20T13:45:22+00:00

This patch removes the following unused EXPORT_SYMBOL's:
- elv_requeue_request
- elv_completed_request

They are only used by the block core, hence they need not be exported.

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

[PATCH] Don't pass boot parameters to argv_init[]

2006-03-31T20:18:53+00:00

The boot cmdline is parsed in parse_early_param() and
parse_args(,unknown_bootoption).

And __setup() is used in obsolete_checksetup().

	start_kernel()
		-> parse_args()
			-> unknown_bootoption()
				-> obsolete_checksetup()

If __setup()'s callback (->setup_func()) returns 1 in
obsolete_checksetup(), obsolete_checksetup() thinks a parameter was
handled.

If ->setup_func() returns 0, obsolete_checksetup() tries other
->setup_func().  If all ->setup_func() that matched a parameter returns 0,
a parameter is seted to argv_init[].

Then, when runing /sbin/init or init=app, argv_init[] is passed to the app.
If the app doesn't ignore those arguments, it will warning and exit.

This patch fixes a wrong usage of it, however fixes obvious one only.

Signed-off-by: OGAWA Hirofumi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

BUG_ON() Conversion in block/elevator.c

2006-03-24T17:43:26+00:00

this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.

Signed-off-by: Eric Sesterhenn 
Signed-off-by: Adrian Bunk

[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23

2006-03-23T19:00:26+00:00

Signed-off-by: Jens Axboe

[PATCH] fix rmmod problems with elevator attributes, clean them up

2006-03-19T03:27:18+00:00

[PATCH] elevator_t lifetime rules and sysfs fixes

2006-03-18T23:35:43+00:00

[PATCH] stop elv_unregister() from rogering other iosched's data, fix locking

2006-03-18T23:34:12+00:00

Signed-off-by: Al Viro

[PATCH] block: implement elv_insert and use it (fix ordcolor flipping bug)

2006-02-08T15:52:58+00:00

q->ordcolor must only be flipped on initial queueing of a hardbarrier
request.

Constructing ordered sequence and requeueing used to pass through
__elv_add_request() which flips q->ordcolor when it sees a barrier
request.

This patch separates out elv_insert() from __elv_add_request() and uses
elv_insert() when constructing ordered sequence and requeueing.
elv_insert() inserts the given request at the specified position and
does nothing else.

Signed-off-by: Tejun Heo 
Acked-by: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds