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* Block: use round_jiffies_up()Alan Stern2008-11-06
| | | | | | | | | | | | | This patch (as1159b) changes the timeout routines in the block core to use round_jiffies_up(). There's no point in rounding the timer deadline down, since if it expires too early we will have to restart it. The patch also removes some unnecessary tests when a request is removed from the queue's timer list. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blk: move blk_delete_timer call in end_that_request_lastMike Anderson2008-11-06
| | | | | | | | | | Move the calling blk_delete_timer to later in end_that_request_last to address an issue where blkdev_dequeue_request may have add a timer for the request. Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* 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: remove unused ll_new_mergeable()FUJITA Tomonori2008-11-06
| | | | | Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Merge branch 'proc' of ↵Linus Torvalds2008-10-23
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc * 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc: (35 commits) proc: remove fs/proc/proc_misc.c proc: move /proc/vmcore creation to fs/proc/vmcore.c proc: move pagecount stuff to fs/proc/page.c proc: move all /proc/kcore stuff to fs/proc/kcore.c proc: move /proc/schedstat boilerplate to kernel/sched_stats.h proc: move /proc/modules boilerplate to kernel/module.c proc: move /proc/diskstats boilerplate to block/genhd.c proc: move /proc/zoneinfo boilerplate to mm/vmstat.c proc: move /proc/vmstat boilerplate to mm/vmstat.c proc: move /proc/pagetypeinfo boilerplate to mm/vmstat.c proc: move /proc/buddyinfo boilerplate to mm/vmstat.c proc: move /proc/vmallocinfo to mm/vmalloc.c proc: move /proc/slabinfo boilerplate to mm/slub.c, mm/slab.c proc: move /proc/slab_allocators boilerplate to mm/slab.c proc: move /proc/interrupts boilerplate code to fs/proc/interrupts.c proc: move /proc/stat to fs/proc/stat.c proc: move rest of /proc/partitions code to block/genhd.c proc: move /proc/cpuinfo code to fs/proc/cpuinfo.c proc: move /proc/devices code to fs/proc/devices.c proc: move rest of /proc/locks to fs/locks.c ...
| * proc: move /proc/diskstats boilerplate to block/genhd.cAlexey Dobriyan2008-10-23
| | | | | | | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Jens Axboe <jens.axboe@oracle.com>
| * proc: move rest of /proc/partitions code to block/genhd.cAlexey Dobriyan2008-10-23
| | | | | | | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Jens Axboe <jens.axboe@oracle.com>
* | compat_blkdev_driver_ioctl: Remove unused variable warningLinus Torvalds2008-10-23
| | | | | | | | | | | | Variable 'ret' is no longer used. Don't declare it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | [PATCH] kill the rest of struct file propagation in block ioctlsAl Viro2008-10-21
| | | | | | | | | | | | Now we can switch blkdev_ioctl() block_device/mode Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] get rid of struct file use in blkdev_ioctl() BLKBSZSETAl Viro2008-10-21
| | | | | | | | | | | | | | We need to do bd_claim() only if file hadn't been opened with O_EXCL and then we have no need to use file itself as owner. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] get rid of blkdev_locked_ioctl()Al Viro2008-10-21
| | | | | | | | | | | | | | | | Most of that stuff doesn't need BKL at all; expand in the (only) caller, merge the switch into one there and leave BKL only around the stuff that might actually need it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] get rid of blkdev_driver_ioctl()Al Viro2008-10-21
| | | | | | | | | | | | convert remaining callers to __blkdev_driver_ioctl() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] trim file propagation in block/compat_ioctl.cAl Viro2008-10-21
| | | | | | | | | | | | | | ... and remove the handling of cases when it falls back to native without changing arguments. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] end of methods switch: remove the old onesAl Viro2008-10-21
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] beginning of methods conversionAl Viro2008-10-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To keep the size of changesets sane we split the switch by drivers; to keep the damn thing bisectable we do the following: 1) rename the affected methods, add ones with correct prototypes, make (few) callers handle both. That's this changeset. 2) for each driver convert to new methods. *ALL* drivers are converted in this series. 3) kill the old (renamed) methods. Note that it _is_ a flagday; all in-tree drivers are converted and by the end of this series no trace of old methods remain. The only reason why we do that this way is to keep the damn thing bisectable and allow per-driver debugging if anything goes wrong. New methods: open(bdev, mode) release(disk, mode) ioctl(bdev, mode, cmd, arg) /* Called without BKL */ compat_ioctl(bdev, mode, cmd, arg) locked_ioctl(bdev, mode, cmd, arg) /* Called with BKL, legacy */ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] introduce __blkdev_driver_ioctl()Al Viro2008-10-21
| | | | | | | | | | | | | | | | Analog of blkdev_driver_ioctl() with sane arguments. For now uses fake struct file, by the end of the series it won't and blkdev_driver_ioctl() will become a wrapper around it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] switch scsi_cmd_ioctl() to passing fmode_tAl Viro2008-10-21
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] switch sg_scsi_ioctl() to passing fmode_tAl Viro2008-10-21
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] pass mode instead of file to sg_io()Al Viro2008-10-21
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | [PATCH] introduce fmode_t, do annotationsAl Viro2008-10-21
|/ | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2008-10-17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/linux-2.6-block: block: remove __generic_unplug_device() from exports block: move q->unplug_work initialization blktrace: pass zfcp driver data blktrace: add support for driver data block: fix current kernel-doc warnings block: only call ->request_fn when the queue is not stopped block: simplify string handling in elv_iosched_store() block: fix kernel-doc for blk_alloc_devt() block: fix nr_phys_segments miscalculation bug block: add partition attribute for partition number block: add BIG FAT WARNING to CONFIG_DEBUG_BLOCK_EXT_DEVT softirq: Add support for triggering softirq work on softirqs.
| * block: remove __generic_unplug_device() from exportsJens Axboe2008-10-17
| | | | | | | | | | | | | | The only out-of-core user is IDE, and that should be using blk_start_queueing() instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * block: move q->unplug_work initializationPeter Zijlstra2008-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | modprobe loop; rmmod loop effectively creates a blk_queue and destroys it which results in q->unplug_work being canceled without it ever being initialized. Therefore, move the initialization of q->unplug_work from blk_queue_make_request() to blk_alloc_queue*(). Reported-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * block: fix current kernel-doc warningsRandy Dunlap2008-10-17
| | | | | | | | | | | | | | | | | | | | | | | | Fix block kernel-doc warnings: Warning(linux-2.6.27-git4//fs/block_dev.c:1272): No description found for parameter 'path' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'cpu' Warning(linux-2.6.27-git4//block/blk-core.c:1021): No description found for parameter 'part' Warning(/var/linsrc/linux-2.6.27-git4//block/genhd.c:544): No description found for parameter 'partno' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> 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: fix kernel-doc for blk_alloc_devt()Li Zefan2008-10-17
| | | | | | | | | | | | | | No argument 'gfp_mask' for blk_alloc_devt(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| * block: fix nr_phys_segments miscalculation bugFUJITA Tomonori2008-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes the bug reported by Nikanth Karthikesan <knikanth@suse.de>: http://lkml.org/lkml/2008/10/2/203 The root cause of the bug is that blk_phys_contig_segment miscalculates q->max_segment_size. blk_phys_contig_segment checks: req->biotail->bi_size + next_req->bio->bi_size > q->max_segment_size But blk_recalc_rq_segments might expect that req->biotail and the previous bio in the req are supposed be merged into one segment. blk_recalc_rq_segments might also expect that next_req->bio and the next bio in the next_req are supposed be merged into one segment. In such case, we merge two requests that can't be merged here. Later, blk_rq_map_sg gives more segments than it should. We need to keep track of segment size in blk_recalc_rq_segments and use it to see if two requests can be merged. This patch implements it in the similar way that we used to do for hw merging (virtual merging). Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds2008-10-17
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (39 commits) [SCSI] sd: fix compile failure with CONFIG_BLK_DEV_INTEGRITY=n libiscsi: fix locking in iscsi_eh_device_reset libiscsi: check reason why we are stopping iscsi session to determine error value [SCSI] iscsi_tcp: return a descriptive error value during connection errors [SCSI] libiscsi: rename host reset to target reset [SCSI] iscsi class: fix endpoint id handling [SCSI] libiscsi: Support drivers initiating session removal [SCSI] libiscsi: fix data corruption when target has to resend data-in packets [SCSI] sd: Switch kernel printing level for DIF messages [SCSI] sd: Correctly handle all combinations of DIF and DIX [SCSI] sd: Always print actual protection_type [SCSI] sd: Issue correct protection operation [SCSI] scsi_error: fix target reset handling [SCSI] lpfc 8.2.8 v2 : Add statistical reporting control and additional fc vendor events [SCSI] lpfc 8.2.8 v2 : Add sysfs control of target queue depth handling [SCSI] lpfc 8.2.8 v2 : Revert target busy in favor of transport disrupted [SCSI] scsi_dh_alua: remove REQ_NOMERGE [SCSI] lpfc 8.2.8 : update driver version to 8.2.8 [SCSI] lpfc 8.2.8 : Add MSI-X support [SCSI] lpfc 8.2.8 : Update driver to use new Host byte error code DID_TRANSPORT_DISRUPTED ...
| * [SCSI] block: separate failfast into multiple bits.Mike Christie2008-10-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Multipath is best at handling transport errors. If it gets a device error then there is not much the multipath layer can do. It will just access the same device but from a different path. This patch breaks up failfast into device, transport and driver errors. The multipath layers (md and dm mutlipath) only ask the lower levels to fast fail transport errors. The user of failfast, read ahead, will ask to fast fail on all errors. Note that blk_noretry_request will return true if any failfast bit is set. This allows drivers that do not support the multipath failfast bits to continue to fail on any failfast error like before. Drivers like scsi that are able to fail fast specific errors can check for the specific fail fast type. In the next patch I will convert scsi. Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* | device create: block: convert device_create_drvdata to device_createGreg Kroah-Hartman2008-10-16
|/ | | | | | | Now that device_create() has been audited, rename things back to the original call to be sane. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* block: Switch blk_integrity_compare from bdev to gendiskMartin K. Petersen2008-10-09
| | | | | | | | | | | | 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>
* block: Fix double put in blk_integrity_unregisterMartin K. Petersen2008-10-09
| | | | | | | | | - kobject_del already puts the parent. - Set integrity profile to NULL to prevent stale data. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: remove end_{queued|dequeued}_request()Kiyoshi Ueda2008-10-09
| | | | | | | | | | | | | 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>
* 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>
* blktrace: use BLKTRACE_BDEV_SIZE as the name size for setup structureJens Axboe2008-10-09
| | | | | | | | Define as 32, which is is what BDEVNAME_SIZE is/was as well. This keeps the user interface the same and gets rid of the difference between kernel and user api here. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: add lld busy state exporting interfaceKiyoshi Ueda2008-10-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* block: Fix blk_start_queueing() to not kick a stopped queueElias Oltmanns2008-10-09
| | | | | | | | | blk_start_queueing() should act like the generic queue unplugging and kicking and ignore a stopped queue. Such a queue may not be run until after a call to blk_start_queue(). Signed-off-by: Elias Oltmanns <eo@nebensachen.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: reserve some tags just for sync IOJens Axboe2008-10-09
| | | | | | | | | | By only allowing async IO to consume 3/4 ths of the tag depth, we always have slots free to serve sync IO. This is important to avoid having writes fill the entire tag queue, thus starving reads. Original patch and idea from Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: as/cfq ssd idle check updateJens Axboe2008-10-09
| | | | | | | | | We really need to know about the hardware tagging support as well, since if the SSD does not do tagging then we still want to idle. Otherwise have the same dependent sync IO vs flooding async IO problem as on rotational media. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: add queue flag for SSD/non-rotational devicesJens Axboe2008-10-09
| | | | | | | | | 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>
* block: add a queue flag for request stacking supportKiyoshi Ueda2008-10-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* block: add request submission interfaceKiyoshi Ueda2008-10-09
| | | | | | | | | | | | | | | | | | 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>
* block: add request update interfaceKiyoshi Ueda2008-10-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* block: blk_cleanup_queue() should call blk_sync_queue()Jens Axboe2008-10-09
| | | | | | | | | When a driver calls blk_cleanup_queue(), the device should be fully idle. However, the block layer may have pending plugging timers and the IO schedulers may have pending work in the work queues. So quisce the device by waiting for the timer and flushing the work queues. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: use rq complete marking in blk_abort_request()Jens Axboe2008-10-09
| | | | | | | | | | We cannot abort a request if we raced with the timeout handler already, or with the IO completion. So make blk_abort_request() mark the request as complete, and only continue if we succeeded. Found and suggested by Mike Anderson <andmike@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: add fault injection mechanism for faking request timeoutsJens Axboe2008-10-09
| | | | | | | | 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>
* block: adjust blkdev_issue_discard for swapHugh Dickins2008-10-09
| | | | | | | | | | | | | | | | 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>
* 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>
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