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2006-02-08[PATCH] block: implement elv_insert and use it (fix ordcolor flipping bug)Tejun Heo
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 <htejun@gmail.com> Acked-by: Jens Axboe <axboe@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-05[PATCH] block: request_queue->ordcolor must not be flipped on SOFTBARRIERTejun Heo
q->ordcolor must not be flipped on SOFTBARRIER. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Jens Axboe <axboe@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-24[BLOCK] elevator: allow default scheduler to potentially be modularNate Diller
Jens has decided that allowing the default scheduler to be a module is a bug, and should not be allowed under kconfig. However, I find that scenario useful for debugging, and wish for the kernel to be able to handle this situation without OOPSing, if I enable such an option in the .config directly. This patch dynamically checks for the presence of the compiled-in default, and falls back to no-op, emitting a suitable error message, when the default is not available Tested for a range of boot options on 2.6.16-rc1-mm2. Signed-off-by: Nate Diller <nate.diller@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-24[BLOCK] elevator: default choice selectionNate Diller
My previous default iosched patch did a poor job dealing with the 'elevator=' boot-time option. The old behavior falls back to the compiled-in default if the requested one is not registered at boot time. This patch dynamically evaluates which default to use, and emits a suitable error message when the requested scheduler is not available. It also does the 'as' -> 'anticipatory' conversion before elevator registration, which along with a modified registration function, allows it to correctly indicate which default scheduler is in use. Tested for a range of boot options on 2.6.16-rc1-mm2. Signed-off-by: Nate Diller <nate.diller@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-16[BLOCK] elevator: if specified scheduler is not found, fall back to defaultJens Axboe
Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-16[BLOCK] elevator: Make elevator=as work again for anticipatoryChuck Ebbert
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-12[PATCH] fix queue stalling while barrier sequencingTejun Heo
If ordered tag isn't supported, request ordering for barrier sequencing is performed by queue draining, which basically hangs the request queue until elv_completed_request() reports completion of all previous fs requests. The condition check in elv_completed_request() was only performed for fs requests. If a special request is queued between the last to-be-drained request and the barrier sequence, draining is never completed and the queue is stalled forever. This patch moves the end-of-draining condition check such that it's performed for all requests. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-09make elv_try_merge() static, kill the dead declaration ofCoywolf Qi Hunt
elv_try_last_merge(). Signed-off-by: Coywolf Qi Hunt <qiyong@fc-cn.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-06[BLOCK] reimplement handling of barrier requestTejun Heo
Reimplement handling of barrier requests. * Flexible handling to deal with various capabilities of target devices. * Retry support for falling back. * Tagged queues which don't support ordered tag can do ordered. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2006-01-06[BLOCK] add @uptodate to end_that_request_last() and @error to rq_end_io_fn()Tejun Heo
add @uptodate argument to end_that_request_last() and @error to rq_end_io_fn(). there's no generic way to pass error code to request completion function, making generic error handling of non-fs request difficult (rq->errors is driver-specific and each driver uses it differently). this patch adds @uptodate to end_that_request_last() and @error to rq_end_io_fn(). for fs requests, this doesn't really matter, so just using the same uptodate argument used in the last call to end_that_request_first() should suffice. imho, this can also help the generic command-carrying request jens is working on. Signed-off-by: tejun heo <htejun@gmail.com> Signed-Off-By: Jens Axboe <axboe@suse.de>
2005-11-18[BLOCK] new block/ directory comment tidyCoywolf Qi Hunt
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 <qiyong@fc-cn.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12[BLOCK] elevator: elv_latter/former_request updateTejun Heo
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 <htejun@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12[BLOCK] fix string handling in elv_iosched_storeTejun Heo
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 <htejun@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12[BLOCK] Implement elv_drain_elevator for improved switch error detectionTejun Heo
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 <htejun@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12[BLOCK] elevator: run queue in elevator_switchTejun Heo
elevator_dispatch needs to run queue after forced dispatching; otherwise, the queue might stall. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12[BLOCK] elevator init fixes #2Zachary Amsden
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 <akpm@osdl.org> Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-12[BLOCK] elevator init fixesZachary Amsden
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 <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Jens Axboe <axboe@suse.de>
2005-11-04[BLOCK] Move all core block layer code to new block/ directoryJens Axboe
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 <axboe@suse.de>