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* block: convert bounce, q->bio_split to bioset_init()/mempool_init()Kent Overstreet2018-05-301-2/+1
| | | | | | | | Convert the core block functionality to embedded bio sets. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block drivers/block: Use octal not symbolic permissionsJoe Perches2018-05-241-34/+34
| | | | | | | | | | | | | | | | | | | Convert the S_<FOO> symbolic permissions to their octal equivalents as using octal and not symbolic permissions is preferred by many as more readable. see: https://lkml.org/lkml/2016/8/2/1945 Done with automated conversion via: $ ./scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace <files...> Miscellanea: o Wrapped modified multi-line calls to a single line where appropriate o Realign modified multi-line calls to open parenthesis Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Add sysfs entry for fua supportKent Overstreet2018-05-141-0/+11
| | | | | Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Introduce blk_queue_flag_{set,clear,test_and_{set,clear}}()Bart Van Assche2018-03-081-15/+7
| | | | | | | | | | | | | | | Introduce functions that modify the queue flags and that protect these modifications with the request queue lock. Except for moving one wake_up_all() call from inside to outside a critical section, this patch does not change any functionality. Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Fix a race between request queue removal and the block cgroup controllerBart Van Assche2018-02-281-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid that the following race can occur: blk_cleanup_queue() blkcg_print_blkgs() spin_lock_irq(lock) (1) spin_lock_irq(blkg->q->queue_lock) (2,5) q->queue_lock = &q->__queue_lock (3) spin_unlock_irq(lock) (4) spin_unlock_irq(blkg->q->queue_lock) (6) (1) take driver lock; (2) busy loop for driver lock; (3) override driver lock with internal lock; (4) unlock driver lock; (5) can take driver lock now; (6) but unlock internal lock. This change is safe because only the SCSI core and the NVME core keep a reference on a request queue after having called blk_cleanup_queue(). Neither driver accesses any of the removed data structures between its blk_cleanup_queue() and blk_put_queue() calls. Reported-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Jan Kara <jack@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Protect less code with sysfs_lock in blk_{un,}register_queue()Bart Van Assche2018-01-181-9/+28
| | | | | | | | | | | | | | The __blk_mq_register_dev(), blk_mq_unregister_dev(), elv_register_queue() and elv_unregister_queue() calls need to be protected with sysfs_lock but other code in these functions not. Hence protect only this code with sysfs_lock. This patch fixes a locking inversion issue in blk_unregister_queue() and also in an error path of blk_register_queue(): it is not allowed to hold sysfs_lock around the kobject_del(&q->kobj) call. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: allow gendisk's request_queue registration to be deferredMike Snitzer2018-01-151-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since I can remember DM has forced the block layer to allow the allocation and initialization of the request_queue to be distinct operations. Reason for this is block/genhd.c:add_disk() has requires that the request_queue (and associated bdi) be tied to the gendisk before add_disk() is called -- because add_disk() also deals with exposing the request_queue via blk_register_queue(). DM's dynamic creation of arbitrary device types (and associated request_queue types) requires the DM device's gendisk be available so that DM table loads can establish a master/slave relationship with subordinate devices that are referenced by loaded DM tables -- using bd_link_disk_holder(). But until these DM tables, and their associated subordinate devices, are known DM cannot know what type of request_queue it needs -- nor what its queue_limits should be. This chicken and egg scenario has created all manner of problems for DM and, at times, the block layer. Summary of changes: - Add device_add_disk_no_queue_reg() and add_disk_no_queue_reg() variant that drivers may use to add a disk without also calling blk_register_queue(). Driver must call blk_register_queue() once its request_queue is fully initialized. - Return early from blk_unregister_queue() if QUEUE_FLAG_REGISTERED is not set. It won't be set if driver used add_disk_no_queue_reg() but driver encounters an error and must del_gendisk() before calling blk_register_queue(). - Export blk_register_queue(). These changes allow DM to use add_disk_no_queue_reg() to anchor its gendisk as the "master" for master/slave relationships DM must establish with subordinate devices referenced in DM tables that get loaded. Once all "slave" devices for a DM device are known its request_queue can be properly initialized and then advertised via sysfs -- important improvement being that no request_queue resource initialization performed by blk_register_queue() is missed for DM devices anymore. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: properly protect the 'queue' kobj in blk_unregister_queueMike Snitzer2018-01-151-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original commit e9a823fb34a8b (block: fix warning when I/O elevator is changed as request_queue is being removed) is pretty conflated. "conflated" because the resource being protected by q->sysfs_lock isn't the queue_flags (it is the 'queue' kobj). q->sysfs_lock serializes __elevator_change() (via elv_iosched_store) from racing with blk_unregister_queue(): 1) By holding q->sysfs_lock first, __elevator_change() can complete before a racing blk_unregister_queue(). 2) Conversely, __elevator_change() is testing for QUEUE_FLAG_REGISTERED in case elv_iosched_store() loses the race with blk_unregister_queue(), it needs a way to know the 'queue' kobj isn't there. Expand the scope of blk_unregister_queue()'s q->sysfs_lock use so it is held until after the 'queue' kobj is removed. To do so blk_mq_unregister_dev() must not also take q->sysfs_lock. So rename __blk_mq_unregister_dev() to blk_mq_unregister_dev(). Also, blk_unregister_queue() should use q->queue_lock to protect against any concurrent writes to q->queue_flags -- even though chances are the queue is being cleaned up so no concurrent writes are likely. Fixes: e9a823fb34a8b ("block: fix warning when I/O elevator is changed as request_queue is being removed") Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-sysfs: remove NULL pointer checking in queue_wb_lat_storeweiping zhang2017-11-231-4/+1
| | | | | | | | wbt_init doesn't set q->rq_wb to NULL, if wbt_init return 0, so check return value is enough, remove NULL checking. Signed-off-by: weiping zhang <zhangweiping@didichuxing.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* block: fix warning when I/O elevator is changed as request_queue is being ↵David Jeffery2017-08-281-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | removed There is a race between changing I/O elevator and request_queue removal which can trigger the warning in kobject_add_internal. A program can use sysfs to request a change of elevator at the same time another task is unregistering the request_queue the elevator would be attached to. The elevator's kobject will then attempt to be connected to the request_queue in the object tree when the request_queue has just been removed from sysfs. This triggers the warning in kobject_add_internal as the request_queue no longer has a sysfs directory: kobject_add_internal failed for iosched (error: -2 parent: queue) ------------[ cut here ]------------ WARNING: CPU: 3 PID: 14075 at lib/kobject.c:244 kobject_add_internal+0x103/0x2d0 To fix this warning, we can check the QUEUE_FLAG_REGISTERED flag when changing the elevator and use the request_queue's sysfs_lock to serialize between clearing the flag and the elevator testing the flag. Signed-off-by: David Jeffery <djeffery@redhat.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Fix a blk_exit_rl() regressionBart Van Assche2017-06-141-12/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid that the following complaint is reported: BUG: sleeping function called from invalid context at kernel/workqueue.c:2790 in_atomic(): 1, irqs_disabled(): 0, pid: 41, name: rcuop/3 1 lock held by rcuop/3/41: #0: (rcu_callback){......}, at: [<ffffffff8111f9a2>] rcu_nocb_kthread+0x282/0x500 Call Trace: dump_stack+0x86/0xcf ___might_sleep+0x174/0x260 __might_sleep+0x4a/0x80 flush_work+0x7e/0x2e0 __cancel_work_timer+0x143/0x1c0 cancel_work_sync+0x10/0x20 blk_throtl_exit+0x25/0x60 blkcg_exit_queue+0x35/0x40 blk_release_queue+0x42/0x130 kobject_put+0xa9/0x190 This happens since we invoke callbacks that need to block from the queue release handler. Fix this by pushing the final release to a workqueue. Reported-by: Ross Zwisler <zwisler@gmail.com> Fixes: commit b425e5049258 ("block: Avoid that blk_exit_rl() triggers a use-after-free") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com> Updated changelog Signed-off-by: Jens Axboe <axboe@fb.com>
* block: Avoid that blk_exit_rl() triggers a use-after-freeBart Van Assche2017-06-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the introduction of .init_rq_fn() and .exit_rq_fn() it is essential that the memory allocated for struct request_queue stays around until all blk_exit_rl() calls have finished. Hence make blk_init_rl() take a reference on struct request_queue. This patch fixes the following crash: general protection fault: 0000 [#2] SMP CPU: 3 PID: 28 Comm: ksoftirqd/3 Tainted: G D 4.12.0-rc2-dbg+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 task: ffff88013a108040 task.stack: ffffc9000071c000 RIP: 0010:free_request_size+0x1a/0x30 RSP: 0018:ffffc9000071fd38 EFLAGS: 00010202 RAX: 6b6b6b6b6b6b6b6b RBX: ffff880067362a88 RCX: 0000000000000003 RDX: ffff880067464178 RSI: ffff880067362a88 RDI: ffff880135ea4418 RBP: ffffc9000071fd40 R08: 0000000000000000 R09: 0000000100180009 R10: ffffc9000071fd38 R11: ffffffff81110800 R12: ffff88006752d3d8 R13: ffff88006752d3d8 R14: ffff88013a108040 R15: 000000000000000a FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa8ec1edb00 CR3: 0000000138ee8000 CR4: 00000000001406e0 Call Trace: mempool_destroy.part.10+0x21/0x40 mempool_destroy+0xe/0x10 blk_exit_rl+0x12/0x20 blkg_free+0x4d/0xa0 __blkg_release_rcu+0x59/0x170 rcu_process_callbacks+0x260/0x4e0 __do_softirq+0x116/0x250 smpboot_thread_fn+0x123/0x1e0 kthread+0x109/0x140 ret_from_fork+0x31/0x40 Fixes: commit e9c787e65c0c ("scsi: allocate scsi_cmnd structures as part of struct request") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org> # v4.11+ Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Only register debugfs attributes for blk-mq queuesBart Van Assche2017-05-261-3/+3
| | | | | | | | | | | | | | The code in blk-mq-debugfs.c assumes that it is working on a blk-mq queue and is not intended to work on a blk-sq queue. Hence only register blk-mq debugfs attributes for blk-mq queues. Fixes: commit 9c1051aacde8 ("blk-mq: untangle debugfs and sysfs") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: untangle debugfs and sysfsOmar Sandoval2017-05-041-0/+2
| | | | | | | | | | | | | | Originally, I tied debugfs registration/unregistration together with sysfs. There's no reason to do this, and it's getting in the way of letting schedulers define their own debugfs attributes. Instead, tie the debugfs registration to the lifetime of the structures themselves. The saner lifetimes mean we can also get rid of the extra mq directory and move everything one level up. I.e., nvme0n1/mq/hctx0/tags is now just nvme0n1/hctx0/tags. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: move debugfs declarations to a separate header fileOmar Sandoval2017-05-041-0/+1
| | | | | | | | Preparation for adding more declarations. Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Register <dev>/queue/mq after having registered <dev>/queueBart Van Assche2017-04-261-3/+3
| | | | | | | | | | | | | | A later patch in this series will modify blk_mq_debugfs_register() such that it uses q->kobj.parent to determine the name of a request queue. Hence make sure that that pointer is initialized before blk_mq_debugfs_register() is called. To avoid lock inversion, protect sysfs / debugfs registration with the queue sysfs_lock instead of the global mutex all_q_mutex. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: Make writeback throttling defaults consistent for SQ devicesJan Kara2017-04-191-18/+1
| | | | | | | | | | | | When CFQ is used as an elevator, it disables writeback throttling because they don't play well together. Later when a different elevator is chosen for the device, writeback throttling doesn't get enabled again as it should. Make sure CFQ enables writeback throttling (if it should be enabled by default) when we switch from it to another IO scheduler. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: remove the discard_zeroes_data flagChristoph Hellwig2017-04-081-1/+1
| | | | | | | | | | Now that we use the proper REQ_OP_WRITE_ZEROES operation everywhere we can kill this hack. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge branch 'for-linus' into for-4.12/blockJens Axboe2017-04-071-1/+1
|\ | | | | | | | | | | | | | | | | | | We've added a considerable amount of fixes for stalls and issues with the blk-mq scheduling in the 4.11 series since forking off the for-4.12/block branch. We need to do improvements on top of that for 4.12, so pull in the previous fixes to make our lives easier going forward. Signed-off-by: Jens Axboe <axboe@fb.com>
| * blk-mq-sched: fix crash in switch error pathOmar Sandoval2017-04-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | In elevator_switch(), if blk_mq_init_sched() fails, we attempt to fall back to the original scheduler. However, at this point, we've already torn down the original scheduler's tags, so this causes a crash. Doing the fallback like the legacy elevator path is much harder for mq, so fix it by just falling back to none, instead. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | block: fix leak of q->rq_wbOmar Sandoval2017-03-291-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | CONFIG_DEBUG_TEST_DRIVER_REMOVE found a possible leak of q->rq_wb when a request queue is reregistered. This has been a problem since wbt was introduced, but the WARN_ON(!list_empty(&stats->callbacks)) in the blk-stat rework exposed it. Fix it by cleaning up wbt when we unregister the queue. Fixes: 87760e5eef35 ("block: hook up writeback throttling") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | block: warn if sharing request queue across gendisksOmar Sandoval2017-03-291-0/+7
| | | | | | | | | | | | | | | | | | | | Now that the remaining drivers have been converted to one request queue per gendisk, let's warn if a request queue gets registered more than once. This will catch future drivers which might do it inadvertently or any old drivers that I may have missed. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | blk-throttle: choose a small throtl_slice for SSDShaohua Li2017-03-281-0/+2
| | | | | | | | | | | | | | | | | | The throtl_slice is 100ms by default. This is a long time for SSD, a lot of IO can run. To make cgroups have smoother throughput, we choose a small value (20ms) for SSD. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | blk-throttle: make throtl_slice tunableShaohua Li2017-03-281-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | throtl_slice is important for blk-throttling. It's called slice internally but it really is a time window blk-throttling samples data. blk-throttling will make decision based on the samplings. An example is bandwidth measurement. A cgroup's bandwidth is measured in the time interval of throtl_slice. A small throtl_slice meanse cgroups have smoother throughput but burn more CPUs. It has 100ms default value, which is not appropriate for all disks. A fast SSD can dispatch a lot of IOs in 100ms. This patch makes it tunable. Since throtl_slice isn't a time slice, the sysfs name 'throttle_sample_time' reflects its character better. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | blk-stat: convert to callback-based statistics reportingOmar Sandoval2017-03-211-26/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, statistics are gathered in ~0.13s windows, and users grab the statistics whenever they need them. This is not ideal for both in-tree users: 1. Writeback throttling wants its own dynamically sized window of statistics. Since the blk-stats statistics are reset after every window and the wbt windows don't line up with the blk-stats windows, wbt doesn't see every I/O. 2. Polling currently grabs the statistics on every I/O. Again, depending on how the window lines up, we may miss some I/Os. It's also unnecessary overhead to get the statistics on every I/O; the hybrid polling heuristic would be just as happy with the statistics from the previous full window. This reworks the blk-stats infrastructure to be callback-based: users register a callback that they want called at a given time with all of the statistics from the window during which the callback was active. Users can dynamically bucketize the statistics. wbt and polling both currently use read vs. write, but polling can be extended to further subdivide based on request size. The callbacks are kept on an RCU list, and each callback has percpu stats buffers. There will only be a few users, so the overhead on the I/O completion side is low. The stats flushing is also simplified considerably: since the timer function is responsible for clearing the statistics, we don't have to worry about stale statistics. wbt is a trivial conversion. After the conversion, the windowing problem mentioned above is fixed. For polling, we register an extra callback that caches the previous window's statistics in the struct request_queue for the hybrid polling heuristic to use. Since we no longer have a single stats buffer for the request queue, this also removes the sysfs and debugfs stats entries. To replace those, we add a debugfs entry for the poll statistics. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | blk-stat: use READ and WRITE instead of BLK_STAT_{READ,WRITE}Omar Sandoval2017-03-211-2/+2
|/ | | | | | | | | The stats buckets will become generic soon, so make the existing users use the common READ and WRITE definitions instead of one internal to blk-stat. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: don't call ioc_exit_icq() with the queue lock held for blk-mqJens Axboe2017-03-021-2/+0
| | | | | | | | | | | | | For legacy scheduling, we always call ioc_exit_icq() with both the ioc and queue lock held. This poses a problem for blk-mq with scheduling, since the queue lock isn't what we use in the scheduler. And since we don't need the queue lock held for ioc exit there, don't grab it and leave any extra locking up to the blk-mq scheduler. Reported-by: Paolo Valente <paolo.valente@linaro.org> Tested-by: Paolo Valente <paolo.valente@linaro.org> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: do not allow updates through sysfs until registration completesTahsin Erdogan2017-02-151-7/+12
| | | | | | | | | | | | | | | | | | When a new disk shows up, sysfs queue directory is created before elevator is registered. This allows a user to attempt a scheduler switch even though the initial registration hasn't completed yet. In one scenario, blk_register_queue() calls elv_register_queue() and right before cfq_registered_queue() is called, another process executes elevator_switch() and replaces q->elevator with deadline scheduler. When cfq_registered_queue() executes it interprets e->elevator_data as struct cfq_data even though it is actually struct deadline_data. Grab q->sysfs_lock in blk_register_queue() to synchronize with sysfs callers. Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: optionally merge discontiguous discard bios into a single requestChristoph Hellwig2017-02-081-0/+12
| | | | | | | | | | | | | | Add a new merge strategy that merges discard bios into a request until the maximum number of discard ranges (or the maximum discard size) is reached from the plug merging code. I/O scheduler merging is not wired up yet but might also be useful, although not for fast devices like NVMe which are the only user for now. Note that for now we don't support limiting the size of each discard range, but if needed that can be added later. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq-sched: (un)register elevator when (un)registering queueOmar Sandoval2017-02-061-11/+10
| | | | | | | | | | | I noticed that when booting with a default blk-mq I/O scheduler, the /sys/block/*/queue/iosched directory was missing. However, switching after boot did create the directory. This is because we skip the initial elevator register/unregister when we don't have a ->request_fn(), but we should still do it for the ->mq_ops case. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: move debugfs_remove() of disk dir to blk_release_queue()Omar Sandoval2017-02-021-0/+3
| | | | | | | This needs to happen after we tear down blktrace. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: Dynamically allocate and refcount backing_dev_infoJan Kara2017-02-021-1/+1
| | | | | | | | | | | Instead of storing backing_dev_info inside struct request_queue, allocate it dynamically, reference count it, and free it when the last reference is dropped. Currently only request_queue holds the reference but in the following patch we add other users referencing backing_dev_info. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: Use pointer to backing_dev_info from request_queueJan Kara2017-02-021-4/+4
| | | | | | | | | | | We will want to have struct backing_dev_info allocated separately from struct request_queue. As the first step add pointer to backing_dev_info to request_queue and convert all users touching it. No functional changes in this patch. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: allow specifying size for extra command dataChristoph Hellwig2017-01-271-2/+5
| | | | | | | | | | | This mirrors the blk-mq capabilities to allocate extra drivers-specific data behind struct request by setting a cmd_size field, as well as having a constructor / destructor for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge branch 'for-4.10/block' of git://git.kernel.dk/linux-blockLinus Torvalds2016-12-131-0/+190
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block layer updates from Jens Axboe: "This is the main block pull request this series. Contrary to previous release, I've kept the core and driver changes in the same branch. We always ended up having dependencies between the two for obvious reasons, so makes more sense to keep them together. That said, I'll probably try and keep more topical branches going forward, especially for cycles that end up being as busy as this one. The major parts of this pull request is: - Improved support for O_DIRECT on block devices, with a small private implementation instead of using the pig that is fs/direct-io.c. From Christoph. - Request completion tracking in a scalable fashion. This is utilized by two components in this pull, the new hybrid polling and the writeback queue throttling code. - Improved support for polling with O_DIRECT, adding a hybrid mode that combines pure polling with an initial sleep. From me. - Support for automatic throttling of writeback queues on the block side. This uses feedback from the device completion latencies to scale the queue on the block side up or down. From me. - Support from SMR drives in the block layer and for SD. From Hannes and Shaun. - Multi-connection support for nbd. From Josef. - Cleanup of request and bio flags, so we have a clear split between which are bio (or rq) private, and which ones are shared. From Christoph. - A set of patches from Bart, that improve how we handle queue stopping and starting in blk-mq. - Support for WRITE_ZEROES from Chaitanya. - Lightnvm updates from Javier/Matias. - Supoort for FC for the nvme-over-fabrics code. From James Smart. - A bunch of fixes from a whole slew of people, too many to name here" * 'for-4.10/block' of git://git.kernel.dk/linux-block: (182 commits) blk-stat: fix a few cases of missing batch flushing blk-flush: run the queue when inserting blk-mq flush elevator: make the rqhash helpers exported blk-mq: abstract out blk_mq_dispatch_rq_list() helper blk-mq: add blk_mq_start_stopped_hw_queue() block: improve handling of the magic discard payload blk-wbt: don't throttle discard or write zeroes nbd: use dev_err_ratelimited in io path nbd: reset the setup task for NBD_CLEAR_SOCK nvme-fabrics: Add FC LLDD loopback driver to test FC-NVME nvme-fabrics: Add target support for FC transport nvme-fabrics: Add host support for FC transport nvme-fabrics: Add FC transport LLDD api definitions nvme-fabrics: Add FC transport FC-NVME definitions nvme-fabrics: Add FC transport error codes to nvme.h Add type 0x28 NVME type code to scsi fc headers nvme-fabrics: patch target code in prep for FC transport support nvme-fabrics: set sqe.command_id in core not transports parser: add u64 number parser nvme-rdma: align to generic ib_event logging helper ...
| * block: add support for REQ_OP_WRITE_ZEROESChaitanya Kulkarni2016-12-011-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a new block layer operation to zero out a range of LBAs. This allows to implement zeroing for devices that don't use either discard with a predictable zero pattern or WRITE SAME of zeroes. The prominent example of that is NVMe with the Write Zeroes command, but in the future, this should also help with improving the way zeroing discards work. For this operation, suitable entry is exported in sysfs which indicate the number of maximum bytes allowed in one write zeroes operation by the device. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * blk-wbt: allow wbt to be enabled always through sysfsJens Axboe2016-11-281-6/+16
| | | | | | | | | | | | | | | | | | | | | | Currently there's no way to enable wbt if it's not enabled in the kernel config by default for a device. Allow a write to the 'wbt_lat_usec' queue sysfs file to enable wbt. This is useful for both the kernel config case, but also if the device is CFQ managed and it was turned off by default. Signed-off-by: Jens Axboe <axboe@fb.com>
| * blk-wbt: allow reset of default latency through sysfsJens Axboe2016-11-281-7/+15
| | | | | | | | | | | | | | | | Allow a write of '-1' to reset the default latency target for a given device. This removes knowledge of the different default settings for rotational vs non-rotational from user space. Signed-off-by: Jens Axboe <axboe@fb.com>
| * blk-mq: make the polling code adaptiveJens Axboe2016-11-171-8/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous commit introduced the hybrid sleep/poll mode. Take that one step further, and use the completion latencies to automatically sleep for half the mean completion time. This is a good approximation. This changes the 'io_poll_delay' sysfs file a bit to expose the various options. Depending on the value, the polling code will behave differently: -1 Never enter hybrid sleep mode 0 Use half of the completion mean for the sleep delay >0 Use this specific value as the sleep delay Signed-off-by: Jens Axboe <axboe@fb.com> Tested-By: Stephen Bates <sbates@raithlin.com> Reviewed-By: Stephen Bates <sbates@raithlin.com>
| * blk-mq: implement hybrid poll mode for sync O_DIRECTJens Axboe2016-11-171-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch enables a hybrid polling mode. Instead of polling after IO submission, we can induce an artificial delay, and then poll after that. For example, if the IO is presumed to complete in 8 usecs from now, we can sleep for 4 usecs, wake up, and then do our polling. This still puts a sleep/wakeup cycle in the IO path, but instead of the wakeup happening after the IO has completed, it'll happen before. With this hybrid scheme, we can achieve big latency reductions while still using the same (or less) amount of CPU. Signed-off-by: Jens Axboe <axboe@fb.com> Tested-By: Stephen Bates <sbates@raithlin.com> Reviewed-By: Stephen Bates <sbates@raithlin.com>
| * blk-wbt: remove stat opsJens Axboe2016-11-111-22/+1
| | | | | | | | | | | | | | Again a leftover from when the throttling code was generic. Now that we just have the block user, get rid of the stat ops and indirections. Signed-off-by: Jens Axboe <axboe@fb.com>
| * block: hook up writeback throttlingJens Axboe2016-11-101-0/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable throttling of buffered writeback to make it a lot more smooth, and has way less impact on other system activity. Background writeback should be, by definition, background activity. The fact that we flush huge bundles of it at the time means that it potentially has heavy impacts on foreground workloads, which isn't ideal. We can't easily limit the sizes of writes that we do, since that would impact file system layout in the presence of delayed allocation. So just throttle back buffered writeback, unless someone is waiting for it. The algorithm for when to throttle takes its inspiration in the CoDel networking scheduling algorithm. Like CoDel, blk-wb monitors the minimum latencies of requests over a window of time. In that window of time, if the minimum latency of any request exceeds a given target, then a scale count is incremented and the queue depth is shrunk. The next monitoring window is shrunk accordingly. Unlike CoDel, if we hit a window that exhibits good behavior, then we simply increment the scale count and re-calculate the limits for that scale value. This prevents us from oscillating between a close-to-ideal value and max all the time, instead remaining in the windows where we get good behavior. Unlike CoDel, blk-wb allows the scale count to to negative. This happens if we primarily have writes going on. Unlike positive scale counts, this doesn't change the size of the monitoring window. When the heavy writers finish, blk-bw quickly snaps back to it's stable state of a zero scale count. The patch registers a sysfs entry, 'wb_lat_usec'. This sets the latency target to me met. It defaults to 2 msec for non-rotational storage, and 75 msec for rotational storage. Setting this value to '0' disables blk-wb. Generally, a user would not have to touch this setting. We don't enable WBT on devices that are managed with CFQ, and have a non-root block cgroup attached. If we have a proportional share setup on this particular disk, then the wbt throttling will interfere with that. We don't have a strong need for wbt for that case, since we will rely on CFQ doing that for us. Signed-off-by: Jens Axboe <axboe@fb.com>
| * block: add scalable completion tracking of requestsJens Axboe2016-11-101-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For legacy block, we simply track them in the request queue. For blk-mq, we track them on a per-sw queue basis, which we can then sum up through the hardware queues and finally to a per device state. The stats are tracked in, roughly, 0.1s interval windows. Add sysfs files to display the stats. The feature is off by default, to avoid any extra overhead. In-kernel users of it can turn it on by setting QUEUE_FLAG_STATS in the queue flags. We currently don't turn it on if someone just reads any of the stats files, that is something we could add as well. Signed-off-by: Jens Axboe <axboe@fb.com>
| * blk-sysfs: Add 'chunk_sectors' to sysfs attributesHannes Reinecke2016-10-181-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The queue limits already have a 'chunk_sectors' setting, so we should be presenting it via sysfs. Signed-off-by: Hannes Reinecke <hare@suse.de> [Damien: Updated Documentation/ABI/testing/sysfs-block] Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * block: Add 'zoned' queue limitDamien Le Moal2016-10-181-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the zoned queue limit to indicate the zoning model of a block device. Defined values are 0 (BLK_ZONED_NONE) for regular block devices, 1 (BLK_ZONED_HA) for host-aware zone block devices and 2 (BLK_ZONED_HM) for host-managed zone block devices. The standards defined drive managed model is not defined here since these block devices do not provide any command for accessing zone information. Drive managed model devices will be reported as BLK_ZONED_NONE. The helper functions blk_queue_zoned_model and bdev_zoned_model return the zoned limit and the functions blk_queue_is_zoned and bdev_is_zoned return a boolean for callers to test if a block device is zoned. The zoned attribute is also exported as a string to applications via sysfs. BLK_ZONED_NONE shows as "none", BLK_ZONED_HA as "host-aware" and BLK_ZONED_HM as "host-managed". Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* | mm: don't cap request size based on read-ahead settingJens Axboe2016-12-121-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | We ran into a funky issue, where someone doing 256K buffered reads saw 128K requests at the device level. Turns out it is read-ahead capping the request size, since we use 128K as the default setting. This doesn't make a lot of sense - if someone is issuing 256K reads, they should see 256K reads, regardless of the read-ahead setting, if the underlying device can support a 256K read in a single command. This patch introduces a bdi hint, io_pages. This is the soft max IO size for the lower level, I've hooked it up to the bdev settings here. Read-ahead is modified to issue the maximum of the user request size, and the read-ahead max size, but capped to the max request size on the device side. The latter is done to avoid reading ahead too much, if the application asks for a huge read. With this patch, the kernel behaves like the application expects. Link: http://lkml.kernel.org/r/1479498073-8657-1-git-send-email-axboe@fb.com Signed-off-by: Jens Axboe <axboe@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* blk-mq: register device instead of diskMatias Bjørling2016-09-211-2/+2
| | | | | | | | Enable devices without a gendisk instance to register itself with blk-mq and expose the associated multi-queue sysfs entries. Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: expose QUEUE_FLAG_DAX in sysfsYigal Korman2016-07-201-0/+11
| | | | | | | | | | Provides the ability to identify DAX enabled devices in userspace. Signed-off-by: Yigal Korman <yigal@plexistor.com> Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: add ability to flag write back caching on a deviceJens Axboe2016-04-121-0/+39
| | | | | | | | | | | | | Add an internal helper and flag for setting whether a queue has write back caching, or write through (or none). Add a sysfs file to show this as well, and make it changeable from user space. This will replace the (awkward) blk_queue_flush() interface that drivers currently use to inform the block layer of write cache state and capabilities. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
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