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2018-11-26block: make blk_poll() take a parameter on whether to spin or notJens Axboe
blk_poll() has always kept spinning until it found an IO. This is fine for SYNC polling, since we need to find one request we have pending, but in preparation for ASYNC polling it can be beneficial to just check if we have any entries available or not. Existing callers are converted to pass in 'spin == true', to retain the old behavior. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-26blk-mq: remove 'tag' parameter from mq_ops->poll()Jens Axboe
We always pass in -1 now and none of the callers use the tag value, remove the parameter. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-26blk-mq: when polling for IO, look for any completionJens Axboe
If we want to support async IO polling, then we have to allow finding completions that aren't just for the one we are looking for. Always pass in -1 to the mq_ops->poll() helper, and have that return how many events were found in this poll loop. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-21blk-mq: not embed .mq_kobj and ctx->kobj into queue instanceMing Lei
Even though .mq_kobj, ctx->kobj and q->kobj share same lifetime from block layer's view, actually they don't because userspace may grab one kobject anytime via sysfs. This patch fixes the issue by the following approach: 1) introduce 'struct blk_mq_ctxs' for holding .mq_kobj and managing all ctxs 2) free all allocated ctxs and the 'blk_mq_ctxs' instance in release handler of .mq_kobj 3) grab one ref of .mq_kobj before initializing each ctx->kobj, so that .mq_kobj is always released after all ctxs are freed. This patch fixes kernel panic issue during booting when DEBUG_KOBJECT_RELEASE is enabled. Reported-by: Guenter Roeck <linux@roeck-us.net> Cc: "jianchao.wang" <jianchao.w.wang@oracle.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-19block: Remove bio->bi_iocDamien Le Moal
bio->bi_ioc is never set so always NULL. Remove references to it in bio_disassociate_task() and in rq_ioc() and delete this field from struct bio. With this change, rq_ioc() always returns current->io_context without the need for a bio argument. Further simplify the code and make it more readable by also removing this helper, which also allows to simplify blk_mq_sched_assign_ioc() by removing its bio argument. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Adam Manzanares <adam.manzanares@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-19block: have ->poll_fn() return number of entries polledJens Axboe
We currently only really support sync poll, ie poll with 1 IO in flight. This prepares us for supporting async poll. Note that the returned value isn't necessarily 100% accurate. If poll races with IRQ completion, we assume that the fact that the task is now runnable means we found at least one entry. In reality it could be more than 1, or not even 1. This is fine, the caller will just need to take this into account. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-19block: avoid ordered task state change for polled IOJens Axboe
For the core poll helper, the task state setting don't need to imply any atomics, as it's the current task itself that is being modified and we're not going to sleep. For IRQ driven, the wakeup path have the necessary barriers to not need us using the heavy handed version of the task state setting. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-16block: add queue_is_mq() helperJens Axboe
Various spots check for q->mq_ops being non-NULL, but provide a helper to do this instead. Where the ->mq_ops != NULL check is redundant, remove it. Since mq == rq-based now that legacy is gone, get rid of the queue_is_rq_based() and just use queue_is_mq() everywhere. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: remove the lock argument to blk_alloc_queue_nodeChristoph Hellwig
With the legacy request path gone there is no real need to override the queue_lock. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: remove the unused lock argument to rq_qos_throttleChristoph Hellwig
Unused now that the legacy request path is gone. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: use atomic bitops for ->queue_flagsChristoph Hellwig
->queue_flags is generally not set or cleared in the fast path, and also generally set or cleared one flag at a time. Make use of the normal atomic bitops for it so that we don't need to take the queue_lock, which is otherwise mostly unused in the core block layer now. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: remove deadline __deadline manipulation helpersChristoph Hellwig
No users left since the removal of the legacy request interface, we can remove all the magic bit stealing now and make it a normal field. But use WRITE_ONCE/READ_ONCE on the new deadline field, given that we don't seem to have any mechanism to guarantee a new value actually gets seen by other threads. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-09block: remove req->timeout_listChristoph Hellwig
Unused now that the legacy request path is gone. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08blk-mq: provide a helper to check if a queue is busyJens Axboe
Returns true if the queue currently has requests pending, false if not. DM can use this to replace the atomic_inc/dec they do per device to see if a device is busy. Reviewed-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-08blk-mq-tag: change busy_iter_fn to return whether to continue or notJens Axboe
We have this functionality in sbitmap, but we don't export it in blk-mq for users of the tags busy iteration. This can be useful for stopping the iteration, if the caller doesn't need to find more requests. Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: improve plug list sortingJens Axboe
Currently we only look at the software queue, but with support for multiple maps, we should also look at the hardware queue. This is important since we'll flush out the request list if either the software queue or hardware queue don't match. This sorts by software queue first, then hardware queue if that differs. Finally we sort by request location like before. This minimizes the flush points per plug list. Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: cleanup and improve list insertionJens Axboe
It's somewhat strange to have a list insertion function that relies on the fact that the caller has mapped things correctly. Pass in the hardware queue directly for insertion, which makes for a much cleaner interface and implementation. Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: cache request hardware queue mappingJens Axboe
We call blk_mq_map_queue() a lot, at least two times for each request per IO, sometimes more. Since we now have an indirect call as well in that function. cache the mapping so we don't have to re-call blk_mq_map_queue() for the same request multiple times. Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: separate number of hardware queues from nr_cpu_idsJens Axboe
With multiple maps, nr_cpu_ids is no longer the maximum number of hardware queues we support on a given devices. The initializer of the tag_set can have set ->nr_hw_queues larger than the available number of CPUs, since we can exceed that with multiple queue maps. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: support multiple hctx mapsJens Axboe
Add support for the tag set carrying multiple queue maps, and for the driver to inform blk-mq how many it wishes to support through setting set->nr_maps. This adds an mq_ops helper for drivers that support more than 1 map, mq_ops->rq_flags_to_type(). The function takes request/bio flags and CPU, and returns a queue map index for that. We then use the type information in blk_mq_map_queue() to index the map set. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: allow software queue to map to multiple hardware queuesJens Axboe
The mapping used to be dependent on just the CPU location, but now it's a tuple of (type, cpu) instead. This is a prep patch for allowing a single software queue to map to multiple hardware queues. No functional changes in this patch. This changes the software queue count to an unsigned short to save a bit of space. We can still support 64K-1 CPUs, which should be enough. Add a check to catch a wrap. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: pass in request/bio flags to queue mappingJens Axboe
Prep patch for being able to place request based not just on CPU location, but also on the type of request. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: abstract out queue mapJens Axboe
This is in preparation for allowing multiple sets of maps per queue, if so desired. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: kill q->mq_mapJens Axboe
It's just a pointer to set->mq_map, use that instead. Move the assignment a bit earlier, so we always know it's valid. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: kill request ->cpu memberJens Axboe
This was used for completion placement for the legacy path, but for mq we have rq->mq_ctx->cpu for that. Add a helper to get the request CPU assignment, as the mq_ctx type is private to blk-mq. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: get rid of q->softirq_done_fn()Jens Axboe
With the legacy path gone, all we do is funnel it through the mq_ops->complete() operation. Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: get rid of blk_queued_rq()Jens Axboe
No point in hiding what this does, just open code it in the one spot where we are still using it. Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: remove request_list codeJens Axboe
It's now dead code, nobody uses it. Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: get rid of MQ scheduler ops unionJens Axboe
This is a remnant of when we had ops for both SQ and MQ schedulers. Now it's just MQ, so get rid of the union. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: remove legacy check in queue blk_freeze_queue()Jens Axboe
Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: remove the request_list usageJens Axboe
We don't do anything with it, that's just the legacy path. Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-25blk-mq: place trace_block_getrq() in correct placeXiaoguang Wang
trace_block_getrq() is to indicate a request struct has been allocated for queue, so put it in right place. Reviewed-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-15blk-mq: provide helper for setting up an SQ queue and tag setJens Axboe
This pattern is repeated throughout all the blk-mq conversions. Provide a basic helper to get it done. Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-13blk-mq: fallback to previous nr_hw_queues when updating failsJianchao Wang
When we try to increate the nr_hw_queues, we may fail due to shortage of memory or other reason, then blk_mq_realloc_hw_ctxs stops and some entries in q->queue_hw_ctx are left with NULL. However, because queue map has been updated with new nr_hw_queues, some cpus have been mapped to hw queue which just encounters allocation failure, thus blk_mq_map_queue could return NULL. This will cause panic in following blk_mq_map_swqueue. To fix it, when increase nr_hw_queues fails, fallback to previous nr_hw_queues and post warning. At the same time, driver's .map_queues usually use completion irq affinity to map hw and cpu, fallback nr_hw_queues will cause lack of some cpu's map to hw, so use default blk_mq_map_queues to do that. Reported-by: syzbot+83e8cbe702263932d9d4@syzkaller.appspotmail.com Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-13blk-mq: realloc hctx when hw queue is mapped to another nodeJianchao Wang
When the hw queues and mq_map are updated, a hctx could be mapped to a different numa node. At this moment, we need to realloc the hctx. If fail to do that, go on using previous hctx. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-13blk-mq: change gfp flags to GFP_NOIO in blk_mq_realloc_hw_ctxsJianchao Wang
blk_mq_realloc_hw_ctxs could be invoked during update hw queues. At the momemt, IO is blocked. Change the gfp flags from GFP_KERNEL to GFP_NOIO to avoid forever hang during memory allocation in blk_mq_realloc_hw_ctxs. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-13blk-mq: adjust debugfs and sysfs register when updating nr_hw_queuesJianchao Wang
blk-mq debugfs and sysfs entries need to be removed before updating queue map, otherwise, we get get wrong result there. This patch fixes it and remove the redundant debugfs and sysfs register/unregister operations during __blk_mq_update_nr_hw_queues. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-08blk-mq: complete req in softirq context in case of single queueMing Lei
Lot of controllers may have only one irq vector for completing IO request. And usually affinity of the only irq vector is all possible CPUs, however, on most of ARCH, there may be only one specific CPU for handling this interrupt. So if all IOs are completed in hardirq context, it is inevitable to degrade IO performance because of increased irq latency. This patch tries to address this issue by allowing to complete request in softirq context, like the legacy IO path. IOPS is observed as ~13%+ in the following randread test on raid0 over virtio-scsi. mdadm --create --verbose /dev/md0 --level=0 --chunk=1024 --raid-devices=8 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh /dev/sdi fio --time_based --name=benchmark --runtime=30 --filename=/dev/md0 --nrfiles=1 --ioengine=libaio --iodepth=32 --direct=1 --invalidate=1 --verify=0 --verify_fatal=0 --numjobs=32 --rw=randread --blocksize=4k Cc: Dongli Zhang <dongli.zhang@oracle.com> Cc: Zach Marano <zmarano@google.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-01Merge tag 'v4.19-rc6' into for-4.20/blockJens Axboe
Merge -rc6 in, for two reasons: 1) Resolve a trivial conflict in the blk-mq-tag.c documentation 2) A few important regression fixes went into upstream directly, so they aren't in the 4.20 branch. Signed-off-by: Jens Axboe <axboe@kernel.dk> * tag 'v4.19-rc6': (780 commits) Linux 4.19-rc6 MAINTAINERS: fix reference to moved drivers/{misc => auxdisplay}/panel.c cpufreq: qcom-kryo: Fix section annotations perf/core: Add sanity check to deal with pinned event failure xen/blkfront: correct purging of persistent grants Revert "xen/blkfront: When purging persistent grants, keep them in the buffer" selftests/powerpc: Fix Makefiles for headers_install change blk-mq: I/O and timer unplugs are inverted in blktrace dax: Fix deadlock in dax_lock_mapping_entry() x86/boot: Fix kexec booting failure in the SEV bit detection code bcache: add separate workqueue for journal_write to avoid deadlock drm/amd/display: Fix Edid emulation for linux drm/amd/display: Fix Vega10 lightup on S3 resume drm/amdgpu: Fix vce work queue was not cancelled when suspend Revert "drm/panel: Add device_link from panel device to DRM device" xen/blkfront: When purging persistent grants, keep them in the buffer clocksource/drivers/timer-atmel-pit: Properly handle error cases block: fix deadline elevator drain for zoned block devices ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge drm/syncobj: Don't leak fences when WAIT_FOR_SUBMIT is set ... Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-27block: move call of scheduler's ->completed_request() hookOmar Sandoval
Commit 4bc6339a583c ("block: move blk_stat_add() to __blk_mq_end_request()") consolidated some calls using ktime_get() so we'd only need to call it once. Kyber's ->completed_request() hook also calls ktime_get(), so let's move it to the same place, too. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-27blk-mq: I/O and timer unplugs are inverted in blktraceIlya Dryomov
trace_block_unplug() takes true for explicit unplugs and false for implicit unplugs. schedule() unplugs are implicit and should be reported as timer unplugs. While correct in the legacy code, this has been inverted in blk-mq since 4.11. Cc: stable@vger.kernel.org Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers") Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-26blk-mq: Enable support for runtime power managementBart Van Assche
Now that the blk-mq core processes power management requests (marked with RQF_PREEMPT) in other states than RPM_ACTIVE, enable runtime power management for blk-mq. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-26block: Allow unfreezing of a queue while requests are in progressBart Van Assche
A later patch will call blk_freeze_queue_start() followed by blk_mq_unfreeze_queue() without waiting for q_usage_counter to drop to zero. Make sure that this doesn't cause a kernel warning to appear by switching from percpu_ref_reinit() to percpu_ref_resurrect(). The former namely requires that the refcount it operates on is zero. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-22Merge tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull more block updates from Jens Axboe: - Set of bcache fixes and changes (Coly) - The flush warn fix (me) - Small series of BFQ fixes (Paolo) - wbt hang fix (Ming) - blktrace fix (Steven) - blk-mq hardware queue count update fix (Jianchao) - Various little fixes * tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block: (31 commits) block/DAC960.c: make some arrays static const, shrinks object size blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter blk-mq: init hctx sched after update ctx and hctx mapping block: remove duplicate initialization tracing/blktrace: Fix to allow setting same value pktcdvd: fix setting of 'ret' error return for a few cases block: change return type to bool block, bfq: return nbytes and not zero from struct cftype .write() method block, bfq: improve code of bfq_bfqq_charge_time block, bfq: reduce write overcharge block, bfq: always update the budget of an entity when needed block, bfq: readd missing reset of parent-entity service blk-wbt: fix IO hang in wbt_wait() block: don't warn for flush on read-only device bcache: add the missing comments for smp_mb()/smp_wmb() bcache: remove unnecessary space before ioctl function pointer arguments bcache: add missing SPDX header bcache: move open brace at end of function definitions to next line bcache: add static const prefix to char * array declarations bcache: fix code comments style ...
2018-08-21blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iterJianchao Wang
For blk-mq, part_in_flight/rw will invoke blk_mq_in_flight/rw to account the inflight requests. It will access the queue_hw_ctx and nr_hw_queues w/o any protection. When updating nr_hw_queues and blk_mq_in_flight/rw occur concurrently, panic comes up. Before update nr_hw_queues, the q will be frozen. So we could use q_usage_counter to avoid the race. percpu_ref_is_zero is used here so that we will not miss any in-flight request. The access to nr_hw_queues and queue_hw_ctx in blk_mq_queue_tag_busy_iter are under rcu critical section, __blk_mq_update_nr_hw_queues could use synchronize_rcu to ensure the zeroed q_usage_counter to be globally visible. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-21blk-mq: init hctx sched after update ctx and hctx mappingJianchao Wang
Currently, when update nr_hw_queues, IO scheduler's init_hctx will be invoked before the mapping between ctx and hctx is adapted correctly by blk_mq_map_swqueue. The IO scheduler init_hctx (kyber) may depend on this mapping and get wrong result and panic finally. A simply way to fix this is that switch the IO scheduler to 'none' before update the nr_hw_queues, and then switch it back after update nr_hw_queues. blk_mq_sched_init_/exit_hctx are removed due to nobody use them any more. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-14Merge tag 'for-4.19/block-20180812' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block updates from Jens Axboe: "First pull request for this merge window, there will also be a followup request with some stragglers. This pull request contains: - Fix for a thundering heard issue in the wbt block code (Anchal Agarwal) - A few NVMe pull requests: * Improved tracepoints (Keith) * Larger inline data support for RDMA (Steve Wise) * RDMA setup/teardown fixes (Sagi) * Effects log suppor for NVMe target (Chaitanya Kulkarni) * Buffered IO suppor for NVMe target (Chaitanya Kulkarni) * TP4004 (ANA) support (Christoph) * Various NVMe fixes - Block io-latency controller support. Much needed support for properly containing block devices. (Josef) - Series improving how we handle sense information on the stack (Kees) - Lightnvm fixes and updates/improvements (Mathias/Javier et al) - Zoned device support for null_blk (Matias) - AIX partition fixes (Mauricio Faria de Oliveira) - DIF checksum code made generic (Max Gurtovoy) - Add support for discard in iostats (Michael Callahan / Tejun) - Set of updates for BFQ (Paolo) - Removal of async write support for bsg (Christoph) - Bio page dirtying and clone fixups (Christoph) - Set of bcache fix/changes (via Coly) - Series improving blk-mq queue setup/teardown speed (Ming) - Series improving merging performance on blk-mq (Ming) - Lots of other fixes and cleanups from a slew of folks" * tag 'for-4.19/block-20180812' of git://git.kernel.dk/linux-block: (190 commits) blkcg: Make blkg_root_lookup() work for queues in bypass mode bcache: fix error setting writeback_rate through sysfs interface null_blk: add lock drop/acquire annotation Blk-throttle: reduce tail io latency when iops limit is enforced block: paride: pd: mark expected switch fall-throughs block: Ensure that a request queue is dissociated from the cgroup controller block: Introduce blk_exit_queue() blkcg: Introduce blkg_root_lookup() block: Remove two superfluous #include directives blk-mq: count the hctx as active before allocating tag block: bvec_nr_vecs() returns value for wrong slab bcache: trivial - remove tailing backslash in macro BTREE_FLAG bcache: make the pr_err statement used for ENOENT only in sysfs_attatch section bcache: set max writeback rate when I/O request is idle bcache: add code comments for bset.c bcache: fix mistaken comments in request.c bcache: fix mistaken code comments in bcache.h bcache: add a comment in super.c bcache: avoid unncessary cache prefetch bch_btree_node_get() bcache: display rate debug parameters to 0 when writeback is not running ...
2018-08-09blk-mq: count the hctx as active before allocating tagJianchao Wang
Currently, we count the hctx as active after allocate driver tag successfully. If a previously inactive hctx try to get tag first time, it may fails and need to wait. However, due to the stale tag ->active_queues, the other shared-tags users are still able to occupy all driver tags while there is someone waiting for tag. Consequently, even if the previously inactive hctx is waked up, it still may not be able to get a tag and could be starved. To fix it, we count the hctx as active before try to allocate driver tag, then when it is waiting the tag, the other shared-tag users will reserve budget for it. Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-27Merge tag 'for-linus-20180727' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block fixes from Jens Axboe: "Bigger than usual at this time, mostly due to the O_DIRECT corruption issue and the fact that I was on vacation last week. This contains: - NVMe pull request with two fixes for the FC code, and two target fixes (Christoph) - a DIF bio reset iteration fix (Greg Edwards) - two nbd reply and requeue fixes (Josef) - SCSI timeout fixup (Keith) - a small series that fixes an issue with bio_iov_iter_get_pages(), which ended up causing corruption for larger sized O_DIRECT writes that ended up racing with buffered writes (Martin Wilck)" * tag 'for-linus-20180727' of git://git.kernel.dk/linux-block: block: reset bi_iter.bi_done after splitting bio block: bio_iov_iter_get_pages: pin more pages for multi-segment IOs blkdev: __blkdev_direct_IO_simple: fix leak in error case block: bio_iov_iter_get_pages: fix size of last iovec nvmet: only check for filebacking on -ENOTBLK nvmet: fixup crash on NULL device path scsi: set timed out out mq requests to complete blk-mq: export setting request completion state nvme: if_ready checks to fail io to deleting controller nvmet-fc: fix target sgl list on large transfers nbd: handle unexpected replies better nbd: don't requeue the same request twice.
2018-07-24blk-mq: export setting request completion stateKeith Busch
This is preparing for drivers that want to directly alter the state of their requests. No functional change here. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>