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path: root/include/linux/blkdev.h
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2008-10-09block: gendisk integrity wrapperMartin K. Petersen
This is a wrapper for accessing a gendisk's integrity bits. It allows the integrity support in MD to be compiled with BLK_DEV_INTEGRITY off. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: Switch blk_integrity_compare from bdev to gendiskMartin K. Petersen
The DM and MD integrity support now depends on being able to use gendisks instead of block_devices when comparing integrity profiles. Change function parameters accordingly. Also update comparison logic so that two NULL profiles are a valid configuration. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: revert part of d7533ad0e132f92e75c1b2eb7c26387b25a583c1Jens Axboe
We need bdev_get_integrity() to support the pending md/dm patches. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: remove end_{queued|dequeued}_request()Kiyoshi Ueda
This patch removes end_queued_request() and end_dequeued_request(), which are no longer used. As a results, users of __end_request() became only end_request(). So the actual code in __end_request() is moved to end_request() and __end_request() is removed. 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>
2008-10-09block: add lld busy state exporting interfaceKiyoshi Ueda
This patch adds an new interface, blk_lld_busy(), to check lld's busy state from the block layer. blk_lld_busy() calls down into low-level drivers for the checking if the drivers set q->lld_busy_fn() using blk_queue_lld_busy(). This resolves a performance problem on request stacking devices below. Some drivers like scsi mid layer stop dispatching request when they detect busy state on its low-level device like host/target/device. It allows other requests to stay in the I/O scheduler's queue for a chance of merging. Request stacking drivers like request-based dm should follow the same logic. However, there is no generic interface for the stacked device to check if the underlying device(s) are busy. If the request stacking driver dispatches and submits requests to the busy underlying device, the requests will stay in the underlying device's queue without a chance of merging. This causes performance problem on burst I/O load. With this patch, busy state of the underlying device is exported via q->lld_busy_fn(). So the request stacking driver can check it and stop dispatching requests if busy. The underlying device driver must return the busy state appropriately: 1: when the device driver can't process requests immediately. 0: when the device driver can process requests immediately, including abnormal situations where the device driver needs to kill all requests. Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: add queue flag for SSD/non-rotational devicesJens Axboe
We don't want to idle in AS/CFQ if the device doesn't have a seek penalty. So add a QUEUE_FLAG_NONROT to indicate a non-rotational device, low level drivers should set this flag upon discovery of an SSD or similar device type. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: add a queue flag for request stacking supportKiyoshi Ueda
This patch adds a queue flag to indicate the block device can be used for request stacking. Request stacking drivers need to stack their devices on top of only devices of which q->request_fn is functional. Since bio stacking drivers (e.g. md, loop) basically initialize their queue using blk_alloc_queue() and don't set q->request_fn, the check of (q->request_fn == NULL) looks enough for that purpose. However, dm will become both types of stacking driver (bio-based and request-based). And dm will always set q->request_fn even if the dm device is bio-based of which q->request_fn is not functional actually. So we need something else to distinguish the type of the device. Adding a queue flag is a solution for that. The reason why dm always sets q->request_fn is to keep the compatibility of dm user-space tools. Currently, all dm user-space tools are using bio-based dm without specifying the type of the dm device they use. To use request-based dm without changing such tools, the kernel must decide the type of the dm device automatically. The automatic type decision can't be done at the device creation time and needs to be deferred until such tools load a mapping table, since the actual type is decided by dm target type included in the mapping table. So a dm device has to be initialized using blk_init_queue() so that we can load either type of table. Then, all queue stuffs are set (e.g. q->request_fn) and we have no element to distinguish that it is bio-based or request-based, even after a table is loaded and the type of the device is decided. By the way, some stuffs of the queue (e.g. request_list, elevator) are needless when the dm device is used as bio-based. But the memory size is not so large (about 20[KB] per queue on ia64), so I hope the memory loss can be acceptable for bio-based dm users. 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>
2008-10-09block: add request submission interfaceKiyoshi Ueda
This patch adds blk_insert_cloned_request(), a generic request submission interface for request stacking drivers. Request-based dm will use it to submit their clones to underlying devices. blk_rq_check_limits() is also added because it is possible that the lower queue has stronger limitations than the upper queue if multiple drivers are stacking at request-level. Not only for blk_insert_cloned_request()'s internal use, the function will be used by request-based dm when the queue limitation is modified (e.g. by replacing dm's table). 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>
2008-10-09block: add request update interfaceKiyoshi Ueda
This patch adds blk_update_request(), which updates struct request with completing its data part, but doesn't complete the struct request itself. Though it looks like end_that_request_first() of older kernels, blk_update_request() should be used only by request stacking drivers. Request-based dm will use it in bio->bi_end_io callback to update the original request when a data part of a cloned request completes. Followings are additional background information of why request-based dm needs this interface. - Request stacking drivers can't use blk_end_request() directly from the lower driver's completion context (bio->bi_end_io or rq->end_io), because some device drivers (e.g. ide) may try to complete their request with queue lock held, and it may cause deadlock. See below for detailed description of possible deadlock: <http://marc.info/?l=linux-kernel&m=120311479108569&w=2> - To solve that, request-based dm offloads the completion of cloned struct request to softirq context (i.e. using blk_complete_request() from rq->end_io). - Though it is possible to use the same solution from bio->bi_end_io, it will delay the notification of bio completion to the original submitter. Also, it will cause inefficient partial completion, because the lower driver can't perform the cloned request anymore and request-based dm needs to requeue and redispatch it to the lower driver again later. That's not good. - So request-based dm needs blk_update_request() to perform the bio completion in the lower driver's completion context, which is more efficient. 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>
2008-10-09block: cleanup some of the integrity stuff in blkdev.hJens Axboe
Don't put functions that are only used in fs/bio-integrity.c in blkdev.h, it's much cleaner to just keep it in there. Also kill completely unused bdev_get_tag_size() Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: add fault injection mechanism for faking request timeoutsJens Axboe
Only works for the generic request timer handling. Allows one to sporadically ignore request completions, thus exercising the timeout handling. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: adjust blkdev_issue_discard for swapHugh Dickins
Two mods to blkdev_issue_discard(), thinking ahead to its use on swap: 1. Add gfp_mask argument, so swap allocation can use it where GFP_KERNEL might deadlock but GFP_NOIO is safe. 2. Enlarge nr_sects argument from unsigned to sector_t: unsigned long is enough to cover a whole swap area, but sector_t suits any partition. Change sb_issue_discard()'s nr_blocks to sector_t too; but no need seen for a gfp_mask there, just pass GFP_KERNEL down to blkdev_issue_discard(). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: Add interface to abort queued requestsMike Anderson
Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: unify request timeout handlingJens Axboe
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>
2008-10-09block: add blk_rq_aligned helper functionFUJITA Tomonori
This adds blk_rq_aligned helper function to see if alignment and padding requirement is satisfied for DMA transfer. This also converts blk_rq_map_kern and __blk_rq_map_user to use the helper function. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: introduce struct rq_map_data to use reserved pagesFUJITA Tomonori
This patch introduces struct rq_map_data to enable bio_copy_use_iov() use reserved pages. Currently, bio_copy_user_iov allocates bounce pages but drivers/scsi/sg.c wants to allocate pages by itself and use them. struct rq_map_data can be used to pass allocated pages to bio_copy_user_iov. The current users of bio_copy_user_iov simply passes NULL (they don't want to use pre-allocated pages). Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Douglas Gilbert <dougg@torque.net> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: add gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iovFUJITA Tomonori
Currently, blk_rq_map_user and blk_rq_map_user_iov always do GFP_KERNEL allocation. This adds gfp_mask argument to blk_rq_map_user and blk_rq_map_user_iov so sg can use it (sg always does GFP_ATOMIC allocation). Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Douglas Gilbert <dougg@torque.net> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: inherit CPU completion on bio->rq and rq->rq mergesJens Axboe
Somewhat incomplete, as we do allow merges of requests and bios that have different completion CPUs given. This is done on the assumption that a larger IO is still more beneficial than CPU locality. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: add support for IO CPU affinityJens Axboe
This patch adds support for controlling the IO completion CPU of either all requests on a queue, or on a per-request basis. We export a sysfs variable (rq_affinity) which, if set, migrates completions of requests to the CPU that originally submitted it. A bio helper (bio_set_completion_cpu()) is also added, so that queuers can ask for completion on that specific CPU. In testing, this has been show to cut the system time by as much as 20-40% on synthetic workloads where CPU affinity is desired. This requires a little help from the architecture, so it'll only work as designed for archs that are using the new generic smp helper infrastructure. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09block: make kblockd_schedule_work() take the queue as parameterJens Axboe
Preparatory patch for checking queuing affinity. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09drop vmerge accountingMikulas Patocka
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>
2008-10-09virtio_blk: use a wrapper function to access io context information of IO ↵Fernando Luis Vázquez Cao
requests struct request has an ioprio member but it is never updated because currently bios do not hold io context information. The implication of this is that virtio_blk ends up passing useless information to the backend driver. That said, some IO schedulers such as CFQ do store io context information in struct request, but use private members for that, which means that that information cannot be directly accessed in a IO scheduler-independent way. This patch adds a function to obtain the ioprio of a request. We should avoid accessing ioprio directly and use this function instead, so that its users do not have to care about future changes in block layer structures or what the currently active IO controller is. This patch does not introduce any functional changes but paves the way for future clean-ups and enhancements. Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09Kill REQ_TYPE_FLUSHDavid Woodhouse
It was only used by ps3disk, and it should probably have been REQ_TYPE_LINUX_BLOCK + REQ_LB_OP_FLUSH. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09Allow elevators to sort/merge discard requestsDavid Woodhouse
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>
2008-10-09Support 'discard sectors' operation in translation layer support coreDavid Woodhouse
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09Add 'discard' request handlingDavid Woodhouse
Some block devices benefit from a hint that they can forget the contents of certain sectors. Add basic support for this to the block core, along with a 'blkdev_issue_discard()' helper function which issues such requests. The caller doesn't get to provide an end_io functio, since blkdev_issue_discard() will automatically split the request up into multiple bios if appropriate. Neither does the function wait for completion -- it's expected that callers won't care about when, or even _if_, the request completes. It's only a hint to the device anyway. By definition, the file system doesn't _care_ about these sectors any more. [With feedback from OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> and Jens Axboe <jens.axboe@oracle.com] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09Fix up comments about matching flags between bio and rqDavid Woodhouse
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-09-11block: disable sysfs parts of the disk command filterJens Axboe
We still have life time issues with the sysfs command filter kobject, so disable it for 2.6.27 release. We can revisit this and make it work properly for 2.6.28, for 2.6.27 release it's too risky. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-08-27block: remove blk_queue_tag_depth() and blk_queue_tag_queue()Jens Axboe
They are unused and ->busy doesn't exist anymore. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-08-27block: rename blk_scsi_cmd_filter to blk_cmd_filterFUJITA Tomonori
Technically, the cmd_filter would be applied to other protocols though it's unlikely to happen. Putting SCSI stuff to request_queue is kinda layer violation. So let's rename it. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-08-27block: move cmdfilter from gendisk to request_queueFUJITA Tomonori
cmd_filter works only for the block layer SG_IO with SCSI block devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI character devices (such as st). We hit a kernel crash with them. The problem is that cmd_filter code accesses to gendisk (having struct blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only SCSI block device files. With character device files, inode->i_bdev leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter isn't safe. SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be independent on any protocols. We shouldn't change ULDs to expose their gendisk. This patch moves struct blk_scsi_cmd_filter from gendisk to request_queue, a common object, which eveyone can access to. The user interface doesn't change; users can change the filters via /sys/block/. gendisk has a pointer to request_queue so the cmd_filter code accesses to struct blk_scsi_cmd_filter. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-08-01block: add a blk_plug_device_unlocked() that grabs the queue lockJens Axboe
blk_plug_device() must be called with the queue lock held, so callers often just grab and release the lock for that purpose. Add a helper that does just that. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-16block: Trivial fix for blk_integrity_rq()Martin K. Petersen
Fail integrity check gracefully when request does not have a bio attached (BLOCK_PC). Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6: (80 commits) ide-floppy: fix unfortunate function naming ide-tape: unify idetape_create_read/write_cmd ide: add ide_pc_intr() helper ide-{floppy,scsi}: read Status Register before stopping DMA engine ide-scsi: add more debugging to idescsi_pc_intr() ide-scsi: use pc->callback ide-floppy: add more debugging to idefloppy_pc_intr() ide-tape: always log debug info in idetape_pc_intr() if debugging is enabled ide-tape: add ide_tape_io_buffers() helper ide-tape: factor out DSC handling from idetape_pc_intr() ide-{floppy,tape}: move checking of ->failed_pc to ->callback ide: add ide_issue_pc() helper ide: add PC_FLAG_DRQ_INTERRUPT pc flag ide-scsi: move idescsi_map_sg() call out from idescsi_issue_pc() ide: add ide_transfer_pc() helper ide-scsi: set drive->scsi flag for devices handled by the driver ide-{cd,floppy,tape}: remove checking for drive->scsi ide: add PC_FLAG_ZIP_DRIVE pc flag ide-tape: factor out waiting for good ireason from idetape_transfer_pc() ide-tape: set PC_FLAG_DMA_IN_PROGRESS flag in idetape_transfer_pc() ...
2008-07-15block: unexport blk_end_sync_rqFUJITA Tomonori
All the users of blk_end_sync_rq has gone (they are converted to use blk_execute_rq). This unexports blk_end_sync_rq. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Borislav Petkov <petkovbb@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-07-04block: add blk_queue_update_dma_padFUJITA Tomonori
This adds blk_queue_update_dma_pad to prevent LLDs from overwriting the dma pad mask wrongly (we added blk_queue_update_dma_alignment due to the same reason). This also converts libata to use blk_queue_update_dma_pad instead of blk_queue_dma_pad. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Tejun Heo <htejun@gmail.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03block: extend queue_flag bitopsJens Axboe
Add test_and_clear and test_and_set. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03Add bvec_merge_data to handle stacked devices and ->merge_bvec()Alasdair G Kergon
When devices are stacked, one device's merge_bvec_fn may need to perform the mapping and then call one or more functions for its underlying devices. The following bio fields are used: bio->bi_sector bio->bi_bdev bio->bi_size bio->bi_rw using bio_data_dir() This patch creates a new struct bvec_merge_data holding a copy of those fields to avoid having to change them directly in the struct bio when going down the stack only to have to change them back again on the way back up. (And then when the bio gets mapped for real, the whole exercise gets repeated, but that's a problem for another day...) Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Neil Brown <neilb@suse.de> Cc: Milan Broz <mbroz@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03block: integrity flags can't use bit ops on unsigned shortJens Axboe
Just use normal open coded bit operations instead, they need not be atomic. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03allow userspace to modify scsi command filter on per device basisAdel Gadllah
This patch exports the per-gendisk command filter to user space through sysfs, so it can be changed by the system administrator. All users of the old cmd filter have been converted to use the new one. Original patch from Peter Jones. Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com> Signed-off-by: Peter Jones <pjones@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03block: integrity cleanupsJens Axboe
- No need to check for NULL bio, we'll get an immediate oops anyway. - Make bio_integrity() a proper function. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03block: blkdev.h cleanup, move iocontext stuff to iocontext.hJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03block: Block layer data integrity supportMartin K. Petersen
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>
2008-07-03block: kill request_queue_tJens Axboe
Everything was moved to struct request_queue a few kernel revisions ago, maintaining the deprecated typedef to avoid breaking things. Now the time has come to get rid of that typedef. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29Improve queue_is_locked()Jens Axboe
spin_is_locked() doesn't work on UP without spinlock debugging. Make it safer and just return 1 on UP, so we don't get false positives. The plan is to kill this debug function during the -rc cycle. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29block: fix queue locking verificationLinus Torvalds
The new queue_flag_set/clear() functions verify that the queue is locked, but in doing so they will actually instead oops if the queue lock hasn't been initialized at all. So fix the lock debug test to consider the "no lock" case to be unlocked. This way you get a nice WARN_ON_ONCE() instead of a fatal oops. Bug introduced by commit 75ad23bc0fcb4f992a5d06982bf0857ab1738e9e ("block: make queue flags non-atomic"). Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29block: Skip I/O merges when disabledAlan D. Brunelle
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>
2008-04-29block: add large command supportFUJITA Tomonori
This patch changes rq->cmd from the static array to a pointer to support large commands. We rarely handle large commands. So for optimization, a struct request still has a static array for a command. rq_init sets rq->cmd pointer to the static array. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29block: rename and export rq_init()FUJITA Tomonori
This rename rq_init() blk_rq_init() and export it. Any path that hands the request to the block layer needs to call it to initialize the request. This is a preparation for large command support, which needs to initialize the request in a proper way (that is, just doing a memset() will not work). Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29block: make queue flags non-atomicNick Piggin
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>