linux.git/block/elevator.c, branch v2.6.15

[BLOCK] new block/ directory comment tidy

2005-11-18T20:59:31+00:00

Some leftover comments referring to drivers/block that are now block/.
They don't add any information we don't already have, so kill them.

Signed-off-by: Coywolf Qi Hunt 
Signed-off-by: Jens Axboe

[BLOCK] elevator: elv_latter/former_request update

2005-11-12T09:57:05+00:00

With generic dispatch queue update, implicit former/latter request
handling using rq->queuelist.prev/next doesn't work as expected
anymore.  Also, the only iosched dependent on this feature was
noop-iosched and it has been reimplemented to have its own
latter/former methods.  This patch removes implicit former/latter
handling.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

[BLOCK] fix string handling in elv_iosched_store

2005-11-12T09:56:21+00:00

elv_iosched_store doesn't terminate string passed from userspace if
it's too long.  Also, if the written length is zero (probably not
possible), it accesses elevator_name[-1].  This patch fixes both bugs.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

[BLOCK] Implement elv_drain_elevator for improved switch error detection

2005-11-12T09:56:06+00:00

This patch adds request_queue->nr_sorted which keeps the number of
requests in the iosched and implement elv_drain_elevator which
performs forced dispatching.  elv_drain_elevator checks whether
iosched actually dispatches all requests it has and prints error
message if it doesn't.  As buggy forced dispatching can result in
wrong barrier operations, I think this extra check is worthwhile.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

[BLOCK] elevator: run queue in elevator_switch

2005-11-12T09:55:37+00:00

elevator_dispatch needs to run queue after forced dispatching;
otherwise, the queue might stall.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe

[BLOCK] elevator init fixes #2

2005-11-12T09:55:05+00:00

In addition to the first patch, which is probably goodness, I found the
cause of my panic - applying this patch fixes it and now I am booting.
If the chosen_elevator[] is not found, fall back to noop.

Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

[BLOCK] elevator init fixes

2005-11-12T09:54:48+00:00

I got a panic in the elevator code, backtrace :

Unable to handle kernel NULL pointer dereference at virtual address 00000060
..
EIP is at elevator_put+0x0/0x30 (null elevator_type passed)
..
elevator_init+0x38
blk_init_queu_node+0xc9
floppy_init+0xdb
do_initcalls+0x23
init+0x10a
init+0x0

Clearly if the kmalloc here fails, e->elevator_type is not yet set; this
appears to be the correct fix, but I think I probably hit the second case
due to a race condition.  Someone more familiar with the elevator code
should look at this more closely until I can determine if I can reproduce.

Signed-off-by: Zachary Amsden 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

[BLOCK] Move all core block layer code to new block/ directory

2005-11-04T07:43:35+00:00

drivers/block/ is right now a mix of core and driver parts. Lets move
the core parts to a new top level directory. Al will move the fs/
related block parts to block/ next.

Signed-off-by: Jens Axboe