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* block: add timer on blkdev_dequeue_request() not elv_next_request()Tejun Heo2008-11-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Block queue supports two usage models - one where block driver peeks at the front of queue using elv_next_request(), processes it and finishes it and the other where block driver peeks at the front of queue, dequeue the request using blkdev_dequeue_request() and finishes it. The latter is more flexible as it allows the driver to process multiple commands concurrently. These two inconsistent usage models affect the block layer implementation confusing. For some, elv_next_request() is considered the issue point while others consider blkdev_dequeue_request() the issue point. Till now the inconsistency mostly affect only accounting, so it didn't really break anything seriously; however, with block layer timeout, this inconsistency hits hard. Block layer considers elv_next_request() the issue point and adds timer but SCSI layer thinks it was just peeking and when the request can't process the command right away, it's just left there without further processing. This makes the request dangling on the timer list and, when the timer goes off, the request which the SCSI layer and below think is still on the block queue ends up in the EH queue, causing various problems - EH hang (failed count goes over busy count and EH never wakes up), WARN_ON() and oopses as low level driver trying to handle the unknown command, etc. depending on the timing. As SCSI midlayer is the only user of block layer timer at the moment, moving blk_add_timer() to elv_dequeue_request() fixes the problem; however, this two usage models definitely need to be cleaned up in the future. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: only call ->request_fn when the queue is not stoppedJens Axboe2008-10-17
| | | | | | | | | | | | Callers should use either blk_run_queue/__blk_run_queue, or blk_start_queueing() to invoke request handling instead of calling ->request_fn() directly as that does not take the queue stopped flag into account. Also add appropriate comments on the above functions to detail their usage. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: simplify string handling in elv_iosched_store()Li Zefan2008-10-17
| | | | | | | strlcpy() guarantees the dest buffer is NULL teminated. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: change elevator to use __blk_end_request()Kiyoshi Ueda2008-10-09
| | | | | | | | | | This patch converts elevator to use __blk_end_request() directly so that end_{queued|dequeued}_request() can be removed. Related 'uptodate' arguments is converted to 'error'. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: Add interface to abort queued requestsMike Anderson2008-10-09
| | | | | Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: unify request timeout handlingJens Axboe2008-10-09
| | | | | | | | | | | | | Right now SCSI and others do their own command timeout handling. Move those bits to the block layer. Instead of having a timer per command, we try to be a bit more clever and simply have one per-queue. This avoids the overhead of having to tear down and setup a timer for each command, so it will result in a lot less timer fiddling. Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: use linux/uaccess.h in elevator.c instead of asm variantJens Axboe2008-10-09
| | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* drop vmerge accountingMikulas Patocka2008-10-09
| | | | | | | | Remove hw_segments field from struct bio and struct request. Without virtual merge accounting they have no purpose. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Allow elevators to sort/merge discard requestsDavid Woodhouse2008-10-09
| | | | | | | | | | | | | But blkdev_issue_discard() still emits requests which are interpreted as soft barriers, because naïve callers might otherwise issue subsequent writes to those same sectors, which might cross on the queue (if they're reallocated quickly enough). Callers still _can_ issue non-barrier discard requests, but they have to take care of queue ordering for themselves. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: request_module(): use format stringmaximilian attems2008-07-03
| | | | | | | | Avoid bad things happening if the module has a printk control string in its name. Signed-off-by: maximilian attems <max@stro.at> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: Block layer data integrity supportMartin K. Petersen2008-07-03
| | | | | | | | | | | | | | | Some block devices support verifying the integrity of requests by way of checksums or other protection information that is submitted along with the I/O. This patch implements support for generating and verifying integrity metadata, as well as correctly merging, splitting and cloning bios and requests that have this extra information attached. See Documentation/block/data-integrity.txt for more information. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Added in elevator switch message to blktrace streamAlan D. Brunelle2008-05-28
| | | | | Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: remove remaining __FUNCTION__ occurrencesHarvey Harrison2008-05-01
| | | | | | | | | __FUNCTION__ is gcc specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* block: Skip I/O merges when disabledAlan D. Brunelle2008-04-29
| | | | | | | | | | | | | | The block I/O + elevator + I/O scheduler code spend a lot of time trying to merge I/Os -- rightfully so under "normal" circumstances. However, if one were to know that the incoming I/O stream was /very/ random in nature, the cycles are wasted. This patch adds a per-request_queue tunable that (when set) disables merge attempts (beyond the simple one-hit cache check), thus freeing up a non-trivial amount of CPU cycles. Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block/elevator.c:elv_rq_merge_ok() mustn't be inlineAdrian Bunk2008-04-29
| | | | | | | | | | | | | | | | | | | | | This patch fixes the following build error with UML and gcc 4.3: <-- snip --> ... CC block/elevator.o /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c: In function ‘elv_merge’: /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:73: sorry, unimplemented: inlining failed in call to ‘elv_rq_merge_ok’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:103: sorry, unimplemented: called from here /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:73: sorry, unimplemented: inlining failed in call to ‘elv_rq_merge_ok’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:495: sorry, unimplemented: called from here make[2]: *** [block/elevator.o] Error 1 make[1]: *** [block] Error 2 <-- snip --> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: make queue flags non-atomicNick Piggin2008-04-29
| | | | | | | We can save some atomic ops in the IO path, if we clearly define the rules of how to modify the queue flags. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* elevator: make elevator_get() attempt to load the appropriate moduleJens Axboe2008-02-19
| | | | | | | | | | | | Currently we fail if someone requests a valid io scheduler, but it's modular and not currently loaded. That can happen from a driver init asking for a different scheduler, or online switching through sysfs as requested by a user. This patch makes elevator_get() request_module() to attempt to load the appropriate module, instead of requiring that done manually. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: make elevator lib checkpatch compliantJens Axboe2008-02-01
| | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: implement drain buffersJames Bottomley2008-01-28
| | | | | | | | | | | | | | | | | | | | | | | | These DMA drain buffer implementations in drivers are pretty horrible to do in terms of manipulating the scatterlist. Plus they're being done at least in drivers/ide and drivers/ata, so we now have code duplication. The one use case for this, as I understand it is AHCI controllers doing PIO mode to mmc devices but translating this to DMA at the controller level. So, what about adding a callback to the block layer that permits the adding of the drain buffer for the problem devices. The idea is that you'd do this in slave_configure after you find one of these devices. The beauty of doing it in the block layer is that it quietly adds the drain buffer to the end of the sg list, so it automatically gets mapped (and unmapped) without anything unusual having to be done to the scatterlist in driver/scsi or drivers/ata and without any alteration to the transfer length. Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Kobject: rename kobject_init_ng() to kobject_init()Greg Kroah-Hartman2008-01-24
| | | | | | | | | Now that the old kobject_init() function is gone, rename kobject_init_ng() to kobject_init() to clean up the namespace. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Kobject: rename kobject_add_ng() to kobject_add()Greg Kroah-Hartman2008-01-24
| | | | | | | | | Now that the old kobject_add() function is gone, rename kobject_add_ng() to kobject_add() to clean up the namespace. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Kobject: convert block/elevator.c to use kobject_init/add_ng()Greg Kroah-Hartman2008-01-24
| | | | | | | | | | This converts the code to use the new kobject functions, cleaning up the logic in doing so. Cc: Jens Axboe <axboe@kernel.dk> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* block: let elv_register() return voidAdrian Bunk2007-12-18
| | | | | | | | | elv_register() always returns 0, and there isn't anything it does where it should return an error (the only error condition is so grave that it's handled with a BUG_ON). Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* fix typo "insted" -> "instead"Uwe Kleine-König2007-10-19
| | | | | Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de> Signed-off-by: Adrian Bunk <bunk@kernel.org>
* block: Initial support for data-less (or empty) barrier supportJens Axboe2007-10-16
| | | | | | | | | This implements functionality to pass down or insert a barrier in a queue, without having data attached to it. The ->prepare_flush_fn() infrastructure from data barriers are reused to provide this functionality. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: add end_queued_request() and end_dequeued_request() helpersJens Axboe2007-10-16
| | | | | | | We can use this helper in the elevator core for BLKPREP_KILL, and it'll also be useful for the empty barrier patch. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* kobjects: fix up improper use of the kobject name fieldGreg Kroah-Hartman2007-10-12
| | | | | | | A number of different drivers incorrect access the kobject name field directly. This is not correct as the name might not be in the array. Use the proper accessor function instead.
* [BLOCK] Get rid of request_queue_t typedefJens Axboe2007-07-24
| | | | | | | | | Some of the code has been gradually transitioned to using the proper struct request_queue, but there's lots left. So do a full sweet of the kernel and get rid of this typedef and replace its uses with the proper type. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Slab allocators: Replace explicit zeroing with __GFP_ZEROChristoph Lameter2007-07-17
| | | | | | | | | | | | | kmalloc_node() and kmem_cache_alloc_node() were not available in a zeroing variant in the past. But with __GFP_ZERO it is possible now to do zeroing while allocating. Use __GFP_ZERO to remove the explicit clearing of memory via memset whereever we can. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Use list_for_each_entry() instead of list_for_each() in the block deviceMatthias Kaehlcke2007-07-10
| | | | | | | | elevator Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [PATCH] elevator: elv_list_lock does not need irq disablingJens Axboe2007-04-30
| | | | | | It's never grabbed from irq context, so just make it plain spin_lock(). Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* make elv_register() output atomicThibaut VARENE2007-03-27
| | | | | | | | | | | | | | | | Booting 2.6.21-rc3-g45592145 I noticed the following on one of my machines in the bootlog: io scheduler noop registered<6>Time: jiffies clocksource has been installed. io scheduler deadline registered (default) Looking at block/elevator.c, it appears that elv_register() uses two consecutive printks in a non-atomic way, leading to the above glitch. The attached trivial patch fixes this issue, by using a single printk. Signed-off-by: Thibaut VARENE <varenet@parisc-linux.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* elevator: don't sort reads between writesJens Axboe2007-02-11
| | | | | | | Don't allow elv_dispatch_sort() to mix reads and writes together, it's rarely a good idea. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* elevator: abstract out the activate and deactivate functionsJens Axboe2007-02-11
| | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [PATCH] elevator: move clearing of unplug flag earlierLinas Vepstas2007-01-23
| | | | | | | | | | | | | | | | | | | | | | | A flag was recently added to the elevator code to avoid performing an unplug when reuests are being re-queued. The goal of this flag was to avoid a deep recursion that can occur when re-queueing requests after a SCSI device/host reset. See http://lkml.org/lkml/2006/5/17/254 However, that fix added the flag near the bottom of a case statement, where an earlier break (in an if statement) could transport one out of the case, without setting the flag. This patch sets the flag earlier in the case statement. I re-discovered the deep recursion recently during testing; I was told that it was a known problem, and the fix to it was in the kernel I was testing. Indeed it was ... but it didn't fix the bug. With the patch below, I no longer see the bug. Signed-off by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jens Axboe <axboe@suse.de> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] elevator: fixup typo in merge logicJens Axboe2006-12-22
| | | | | | | | | | | | The recent io scheduler allow_merge commit left the block layer with no merging, oops. This patch fixes that up. That means the CFQ change needs to be verified again, it might not fix the original bug now. But that's a seperate thing, I'll double check that tomorrow. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cfq-iosched: don't allow sync merges across queuesJens Axboe2006-12-20
| | | | | | | | | | | | Currently we allow any merge, even if the io originates from different processes. This can cause really bad starvation and unfairness, if those ios happen to be synchronous (reads or direct writes). So add a allow_merge hook to the io scheduler ops, so an io scheduler can help decide whether a bio/process combination may be merged with an existing request. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [BLOCK] Cleanup unused variable passingJens Axboe2006-12-01
| | | | | | | | - ->init_queue() does not need the elevator passed in - ->put_request() is a hot path and need not have the queue passed in - cfq_update_io_seektime() does not need cfqd passed in Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [PATCH] block layer: elv_iosched_show should get elv_list_lockVasily Tarasov2006-10-12
| | | | | | | | elv_iosched_show function iterates other elv_list, hence elv_list_lock should be got. Signed-off-by: Vasily Tarasov <vtaras@openvz.org> Signed-off-by: Vasily Tarasov <jens.axboe@oracle.com>
* [PATCH] block layer: elevator_find function cleanupVasily Tarasov2006-10-12
| | | | | | | | We can easily produce search through the elevator list without introducing additional elevator_type variable. Signed-off-by: Vasily Tarasov <vtaras@openvz.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [PATCH] Update axboe@suse.de email addressJens Axboe2006-09-30
| | | | | | | As people often look for the copyright in files to see who to mail, update the link to a neutral one. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* [PATCH] Make sure all block/io scheduler setups are node awareJens Axboe2006-09-30
| | | | | | | Some were kmalloc_node(), some were still kmalloc(). Change them all to kmalloc_node(). Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] Drop useless bio passing in may_queue/set_request APIJens Axboe2006-09-30
| | | | | | It's not needed for anything, so kill the bio passing. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] Remove ->waiting member from struct requestJens Axboe2006-09-30
| | | | | | | | As the comments indicates in blkdev.h, we can fold it into ->end_io_data usage as that is really what ->waiting is. Fixup the users of blk_end_sync_rq(). Signed-off-by: Jens Axboe <axboe@kernel.dk>
* [PATCH] elevator: abstract out the rbtree sort handlingJens Axboe2006-09-30
| | | | | | | | | | | | The rbtree sort/lookup/reposition logic is mostly duplicated in cfq/deadline/as, so move it to the elevator core. The io schedulers still provide the actual rb root, as we don't want to impose any sort of specific handling on the schedulers. Introduce the helpers and rb_node in struct request to help migrate the IO schedulers. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] elevator: move the backmerging logic into the elevator coreJens Axboe2006-09-30
| | | | | | | | | | | Right now, every IO scheduler implements its own backmerging (except for noop, which does no merging). That results in duplicated code for essentially the same operation, which is never a good thing. This patch moves the backmerging out of the io schedulers and into the elevator core. We save 1.6kb of text and as a bonus get backmerging for noop as well. Win-win! Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] Split struct request ->flags into two partsJens Axboe2006-09-30
| | | | | | | | | | Right now ->flags is a bit of a mess: some are request types, and others are just modifiers. Clean this up by splitting it into ->cmd_type and ->cmd_flags. This allows introduction of generic Linux block message types, useful for sending generic Linux commands to block devices. Signed-off-by: Jens Axboe <axboe@suse.de>
* elv_unregister: fix possible crash on module unloadOleg Nesterov2006-08-22
| | | | | | | | | | An exiting task or process which didn't do I/O yet have no io context, elv_unregister() should check it is not NULL. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Jens Axboe <axboe@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-30
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] remove dead code from elevator switchingDave Jones2006-06-23
| | | | | | | | | | We already drop the refcount in elevator_exit(), and as we're setting 'e' to NULL, we'll never take that branch anyway. Finally, as 'e' is a local var that isn't referenced afterwards, setting it to NULL is pointless. Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Jens Axboe <axboe@suse.de>
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