- 24 Jan, 2018 2 commits
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Johannes Thumshirn authored
Use pr_debug instead of hand crafted macros. This way it is not needed to re-compile the kernel to enable bsg debug outputs and it's possible to selectively enable specific prints. Cc: Joe Perches <joe@perches.com> Reviewed-by:
Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by:
Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by:
Jens Axboe <axboe@kernel.dk>
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Eryu Guan authored
Attributes that only implement .seq_ops are read-only, any write to them should be rejected. But currently kernel would crash when writing to such debugfs entries, e.g. chmod +w /sys/kernel/debug/block/<dev>/requeue_list echo 0 > /sys/kernel/debug/block/<dev>/requeue_list chmod -w /sys/kernel/debug/block/<dev>/requeue_list Fix it by returning -EPERM in blk_mq_debugfs_write() when writing to such attributes. Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by:
Eryu Guan <eguan@redhat.com> Signed-off-by:
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- 23 Jan, 2018 1 commit
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Goldwyn Rodrigues authored
We inadvertently set it again on the source bio, but we need to set it on the new split bio instead. Fixes: fbbaf700 ("block: trace completion of all bios.") Signed-off-by:
Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by:
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- 20 Jan, 2018 1 commit
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weiping zhang authored
use queue_is_rq_based instead of open code. Signed-off-by:
weiping zhang <zhangweiping@didichuxing.com> Signed-off-by:
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- 19 Jan, 2018 6 commits
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Bart Van Assche authored
The previous patch removed all users of these two functions. Hence also remove the functions themselves. Reviewed-by:
Mike Snitzer <snitzer@redhat.com> Signed-off-by:
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Bart Van Assche authored
Make sure that calling blk_mq_run_hw_queue() or blk_mq_kick_requeue_list() triggers a queue run without delay even if blk_mq_delay_run_hw_queue() has been called recently and if its delay has not yet expired. Reviewed-by:
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Bart Van Assche authored
Most blk-mq functions have a name that follows the pattern blk_mq_${action}. However, the function name blk_mq_request_direct_issue is an exception. Hence rename this function. This patch does not change any functionality. Reviewed-by: -
Bart Van Assche authored
This patch avoids that workloads with large block sizes (megabytes) can trigger the following call stack with the ib_srpt driver (that driver is the only driver that chains scatterlists allocated by sgl_alloc_order()): BUG: Bad page state in process kworker/0:1H pfn:2423a78 page:fffffb03d08e9e00 count:-3 mapcount:0 mapping: (null) index:0x0 flags: 0x57ffffc0000000() raw: 0057ffffc0000000 0000000000000000 0000000000000000 fffffffdffffffff raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000 page dumped because: nonzero _count CPU: 0 PID: 733 Comm: kworker/0:1H Tainted: G I 4.15.0-rc7.bart+ #1 Hardware name: HP ProLiant DL380 G7, BIOS P67 08/16/2015 Workqueue: ib-comp-wq ib_cq_poll_work [ib_core] Call Trace: dump_stack+0x5c/0x83 bad_page+0xf5/0x10f get_page_from_freelist+0xa46/0x11b0 __alloc_pages_nodemask+0x103/0x290 sgl_alloc_order+0x101/0x180 target_alloc_sgl+0x2c/0x40 [target_core_mod] srpt_alloc_rw_ctxs+0x173/0x2d0 [ib_srpt] srpt_handle_new_iu+0x61e/0x7f0 [ib_srpt] __ib_process_cq+0x55/0xa0 [ib_core] ib_cq_poll_work+0x1b/0x60 [ib_core] process_one_work+0x141/0x340 worker_thread+0x47/0x3e0 kthread+0xf5/0x130 ret_from_fork+0x1f/0x30 Fixes: e80a0af4 ("lib/scatterlist: Introduce sgl_alloc() and sgl_free()") Reported-by:
Laurence Oberman <loberman@redhat.com> Tested-by:
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git://git.infradead.org/nvmeJens Axboe authored
Pull NVMe fixes for 4.16 from Christoph. * 'nvme-4.16' of git://git.infradead.org/nvme: nvme-pci: clean up SMBSZ bit definitions nvme-pci: clean up CMB initialization nvme-fc: correct hang in nvme_ns_remove() nvme-fc: fix rogue admin cmds stalling teardown nvmet: release a ns reference in nvmet_req_uninit if needed nvme-fabrics: fix memory leak when parsing host ID option nvme: fix comment typos in nvme_create_io_queues nvme: host delete_work and reset_work on separate workqueues nvme-pci: allocate device queues storage space at probe nvme-pci: serialize pci resets
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Joseph Qi authored
In mixed read/write workload on SSD, write latency is much lower than read. But now we only track and record read latency and then use it as threshold base for both read and write io latency accounting. As a result, write io latency will always be considered as good and bad_bio_cnt is much smaller than 20% of bio_cnt. That is to mean, the tg to be checked will be treated as idle most of the time and still let others dispatch more ios, even it is truly running under low limit and wants its low limit to be guaranteed, which is not we expected in fact. So track read and write request individually, which can bring more precise latency control for low limit idle detection. Signed-off-by:
Joseph Qi <qijiang.qj@alibaba-inc.com> Reviewed-by:
Shaohua Li <shli@fb.com> Signed-off-by:
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- 18 Jan, 2018 9 commits
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Ilya Dryomov authored
Similar to blkdev_write_iter(), return -EPERM if the partition is read-only. This covers ioctl(), fallocate() and most in-kernel users but isn't meant to be exhaustive -- everything else will be caught in generic_make_request_checks(), fail with -EIO and can be fixed later. Reviewed-by:
Sagi Grimberg <sagi@grimberg.me> Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Signed-off-by:
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Ilya Dryomov authored
Regular block device writes go through blkdev_write_iter(), which does bdev_read_only(), while zeroout/discard/etc requests are never checked, both userspace- and kernel-triggered. Add a generic catch-all check to generic_make_request_checks() to actually enforce ioctl(BLKROSET) and set_disk_ro(), which is used by quite a few drivers for things like snapshots, read-only backing files/images, etc. Reviewed-by:
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weiping zhang authored
export these two interface for cgroup-v1. Acked-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
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Bart Van Assche authored
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:
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Bart Van Assche authored
This patch does not change any functionality. Reviewed-by:
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Bart Van Assche authored
These two functions are only called from inside the block layer so unexport them. Reviewed-by:
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Paolo Valente authored
To maximise responsiveness, BFQ raises the weight, and performs device idling, for bfq_queues associated with processes deemed as interactive. In particular, weight raising has a maximum duration, equal to the time needed to start a large application. If a weight-raised process goes on doing I/O beyond this maximum duration, it loses weight-raising. This mechanism is evidently vulnerable to the following false positives: I/O-bound applications that will go on doing I/O for much longer than the duration of weight-raising. These applications have basically no benefit from being weight-raised at the beginning of their I/O. On the opposite end, while being weight-raised, these applications a) unjustly steal throughput to applications that may truly need low latency; b) make BFQ uselessly perform device idling; device idling results in loss of device throughput with most flash-based storage, and may increase latencies when used purposelessly. This commit adds a countermeasure to reduce both the above problems. To introduce this countermeasure, we provide the following extra piece of information (full details in the comments added by this commit). During the start-up of the large application used as a reference to set the duration of weight-raising, involved processes transfer at most ~110K sectors each. Accordingly, a process initially deemed as interactive has no right to be weight-raised any longer, once transferred 110K sectors or more. Basing on this consideration, this commit early-ends weight-raising for a bfq_queue if the latter happens to have received an amount of service at least equal to 110K sectors (actually, a little bit more, to keep a safety margin). I/O-bound applications that reach a high throughput, such as file copy, get to this threshold much before the allowed weight-raising period finishes. Thus this early ending of weight-raising reduces the amount of time during which these applications cause the problems described above. Tested-by:
Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by:
Holger Hoffstätte <holger@applied-asynchrony.com> Signed-off-by:
Paolo Valente <paolo.valente@linaro.org> Signed-off-by:
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Paolo Valente authored
Asynchronous I/O can easily starve synchronous I/O (both sync reads and sync writes), by consuming all request tags. Similarly, storms of synchronous writes, such as those that sync(2) may trigger, can starve synchronous reads. In their turn, these two problems may also cause BFQ to loose control on latency for interactive and soft real-time applications. For example, on a PLEXTOR PX-256M5S SSD, LibreOffice Writer takes 0.6 seconds to start if the device is idle, but it takes more than 45 seconds (!) if there are sequential writes in the background. This commit addresses this issue by limiting the maximum percentage of tags that asynchronous I/O requests and synchronous write requests can consume. In particular, this commit grants a higher threshold to synchronous writes, to prevent the latter from being starved by asynchronous I/O. According to the above test, LibreOffice Writer now starts in about 1.2 seconds on average, regardless of the background workload, and apart from some rare outlier. To check this improvement, run, e.g., sudo ./comm_startup_lat.sh bfq 5 5 seq 10 "lowriter --terminate_after_init" for the comm_startup_lat benchmark in the S suite [1]. [1] https://github.com/Algodev-github/STested-by:
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Ming Lei authored
If we run into blk_mq_request_direct_issue(), when queue is busy, we don't want to dispatch this request into hctx->dispatch_list, and what we need to do is to return the queue busy info to caller, so that caller can deal with it well. Fixes: 396eaf21 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback") Reported-by:
Ming Lei <ming.lei@redhat.com> Signed-off-by:
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- 17 Jan, 2018 11 commits
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Bart Van Assche authored
Fixes: 4246a0b6 ("block: add a bi_error field to struct bio") Reviewed-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Christoph Hellwig authored
Define the bit positions instead of macros using the magic values, and move the expanded helpers to calculate the size and size unit into the implementation C file. Signed-off-by:
Keith Busch <keith.busch@intel.com> Reviewed-by:
Logan Gunthorpe <logang@deltatee.com>
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Christoph Hellwig authored
Refactor the call to nvme_map_cmb, and change the conditions for probing for the CMB. First remove the version check as NVMe TPs always apply to earlier versions of the spec as well. Second check for the whole CMBSZ register for support of the CMB feature instead of just the size field inside of it to simplify the code a bit. Signed-off-by:
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James Smart authored
When connectivity is lost to a device, the association is terminated and the blk-mq queues are quiesced/stopped. When connectivity is re-established, they are resumed. If connectivity is lost for a sufficient amount of time that the controller is then deleted, the delete path starts tearing down queues, and eventually calling nvme_ns_remove(). It appears that pending commands may cause blk_cleanup_queue() to never complete and the teardown stalls. Correct by starting the ns queues after transitioning to a DELETING state, allowing pending commands to be flushed with io failures. Thus the delete path is clear when reached. Signed-off-by:
James Smart <james.smart@broadcom.com> Signed-off-by:
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James Smart authored
When connectivity is lost to a device, the association is terminated and the blk-mq queues are quiesced/stopped. When connectivity is re-established, they are resumed. If an admin command is received while connectivity is list, the ioctl queues the command on the admin_q and the command stalls (the thread issuing the ioctl hangs/waits). if the connectivity is lost long enough such that the controller is then deleted, the delete code makes its calls to initiate the delete, which then expects the core layer to call the transport when all references are removed and the controller can be freed. Unfortunately, nothing in this path dequeued the admin command, so a reference sits outstanding and things stop, hanging the delete indefinitely. Correct by unquiescing the admin queue in the delete association. This means any admin command (which should only be from an ioctl) issued after connectivity is lost will detect the controller is in a reconnecting state and will (fast) fail the command. Thus, a pending reference can no longer be created. Once connectivity is re-established, a new ioctl/admin command would see proper device state and function again. Signed-off-by:
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Mike Snitzer authored
After commit: 923218f6 ("blk-mq: don't allocate driver tag upfront for flush rq") we no longer use the 'can_block' argument in blk_mq_sched_insert_request(). Kill it. Signed-off-by:
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Ming Lei authored
blk_insert_cloned_request() is called in the fast path of a dm-rq driver (e.g. blk-mq request-based DM mpath). blk_insert_cloned_request() uses blk_mq_request_bypass_insert() to directly append the request to the blk-mq hctx->dispatch_list of the underlying queue. 1) This way isn't efficient enough because the hctx spinlock is always used. 2) With blk_insert_cloned_request(), we completely bypass underlying queue's elevator and depend on the upper-level dm-rq driver's elevator to schedule IO. But dm-rq currently can't get the underlying queue's dispatch feedback at all. Without knowing whether a request was issued or not (e.g. due to underlying queue being busy) the dm-rq elevator will not be able to provide effective IO merging (as a side-effect of dm-rq currently blindly destaging a request from its elevator only to requeue it after a delay, which kills any opportunity for merging). This obviously causes very bad sequential IO performance. Fix this by updating blk_insert_cloned_request() to use blk_mq_request_direct_issue(). blk_mq_request_direct_issue() allows a request to be issued directly to the underlying queue and returns the dispatch feedback (blk_status_t). If blk_mq_request_direct_issue() returns BLK_SYS_RESOURCE the dm-rq driver will now use DM_MAPIO_REQUEUE to _not_ destage the request. Whereby preserving the opportunity to merge IO. With this, request-based DM's blk-mq sequential IO performance is vastly improved (as much as 3X in mpath/virtio-scsi testing). Signed-off-by:
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Mike Snitzer authored
No functional change. Just makes code flow more logically. In following commit, __blk_mq_try_issue_directly() will be used to return the dispatch result (blk_status_t) to DM. DM needs this information to improve IO merging. Signed-off-by:
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Ming Lei authored
We know this WARN_ON is harmless and in reality it may be trigged, so convert it to printk() and dump_stack() to avoid to confusing people. Also add comment about two releated races here. Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Stefan Haberland <sth@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "jianchao.wang" <jianchao.w.wang@oracle.com> Signed-off-by:
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Ming Lei authored
When hctx->next_cpu is set from possible online CPUs, there is one race in which hctx->next_cpu may be set as >= nr_cpu_ids, and finally break workqueue. The race can be triggered in the following two sitations: 1) when one CPU is becoming DEAD, blk_mq_hctx_notify_dead() is called to dispatch requests from the DEAD cpu context, but at that time, this DEAD CPU has been cleared from 'cpu_online_mask', so all CPUs in hctx->cpumask may become offline, and cause hctx->next_cpu set a bad value. 2) blk_mq_delay_run_hw_queue() is called from CPU B, and found the queue should be run on the other CPU A, then CPU A may become offline at the same time and all CPUs in hctx->cpumask become offline. This patch deals with this issue by re-selecting next CPU, and making sure it is set correctly. Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Stefan Haberland <sth@linux.vnet.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Thomas Gleixner <tglx@linutronix.de> Reported-by:
"jianchao.wang" <jianchao.w.wang@oracle.com> Tested-by:
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Tina Ruchandani authored
'struct frame' uses two variables to store the sent timestamp - 'struct timeval' and jiffies. jiffies is used to avoid discrepancies caused by updates to system time. 'struct timeval' is deprecated because it uses 32-bit representation for seconds which will overflow in year 2038. This patch does the following: - Replace the use of 'struct timeval' and jiffies with ktime_t, which is the recommended type for timestamping - ktime_t provides both long range (like jiffies) and high resolution (like timeval). Using ktime_get (monotonic time) instead of wall-clock time prevents any discprepancies caused by updates to system time. [updates by Arnd below] The original patch from Tina never went anywhere as we discussed how to keep the impact on performance minimal. I've started over now but arrived at basically the same patch that she had originally, except for an slightly improved tsince_hr() function. I'm making it more robust against overflows, and also optimize explicitly for the common case in which a frame is less than 4.2 seconds old, using only a 32-bit division in that case. This should make the new version more efficient than the old code, since we replace the existing two 32-bit division in do_gettimeofday() plus one multiplication with a single single 32-bit division in tsince_hr() and drop the double bookkeeping. It's also more efficient than the ktime_get_us() API we discussed before, since that would also rely on multiple divisions. Link: https://lists.linaro.org/pipermail/y2038/2015-May/000276.htmlSigned-off-by:
Tina Ruchandani <ruchandani.tina@gmail.com> Cc: Ed Cashin <ed.cashin@acm.org> Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
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- 16 Jan, 2018 1 commit
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Arnd Bergmann authored
Some older compilers (gcc-4.4 through 4.6 in particular) struggle with the way that blkg_rwstat_read() returns a structure, leading to excessive stack usage and rather inefficient code: block/blk-cgroup.c: In function 'blkg_destroy': block/blk-cgroup.c:354:1: error: the frame size of 1296 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] block/cfq-iosched.c: In function 'cfqg_stats_add_aux': block/cfq-iosched.c:753:1: error: the frame size of 1928 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] block/bfq-cgroup.c: In function 'bfqg_stats_add_aux': block/bfq-cgroup.c:299:1: error: the frame size of 1928 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] I also notice that there is no point in using atomic accesses for the local variables, so storing the temporaries in simple 'u64' variables not only avoids the stack usage on older compilers but also improves the object code on modern versions. Fixes: e6269c44 ("blkcg: add blkg_[rw]stat->aux_cnt and replace cfq_group->dead_stats with it") Acked-by:
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- 15 Jan, 2018 9 commits
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Sagi Grimberg authored
nvmet_req_init looked up a namespace and took a reference on it (unless it failed prior to that). If the request is uninitialized (in error cases) we need to remove that reference in case it was taken, otherwise we leak namespace reference when calling nvme_req_uninit. Signed-off-by:
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Roland Dreier authored
We use match_strdup() to get a copy of the option string for host ID string, but we just pass it to uuid_parse() and don't store the string pointer, so we need to kfree() the string after parsing it. Signed-off-by:
Roland Dreier <roland@purestorage.com> Reviewed-by:
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Minwoo Im authored
fix comment typos in nvme_create_io_queues() like below. _aount_ to _amount_ _an_ to _can_ Signed-off-by:
Minwoo Im <minwoo.im.dev@gmail.com> Reviewed-by:
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Roy Shterman authored
We need to ensure that delete_work will be hosted on a different workqueue than all the works we flush or cancel from it. Otherwise we may hit a circular dependency warning [1]. Also, given that delete_work flushes reset_work, host reset_work on nvme_reset_wq and delete_work on nvme_delete_wq. In addition, fix the flushing in the individual drivers to flush nvme_delete_wq when draining queued deletes. [1]: [ 178.491942] ============================================= [ 178.492718] [ INFO: possible recursive locking detected ] [ 178.493495] 4.9.0-rc4-c844263313a8-lb #3 Tainted: G OE [ 178.494382] --------------------------------------------- [ 178.495160] kworker/5:1/135 is trying to acquire lock: [ 178.495894] ( [ 178.496120] "nvme-wq" [ 178.496471] ){++++.+} [ 178.496599] , at: [ 178.496921] [<ffffffffa70ac206>] flush_work+0x1a6/0x2d0 [ 178.497670] but task is already holding lock: [ 178.498499] ( [ 178.498724] "nvme-wq" [ 178.499074] ){++++.+} [ 178.499202] , at: [ 178.499520] [<ffffffffa70ad6c2>] process_one_work+0x162/0x6a0 [ 178.500343] other info that might help us debug this: [ 178.501269] Possible unsafe locking scenario: [ 178.502113] CPU0 [ 178.502472] ---- [ 178.502829] lock( [ 178.503115] "nvme-wq" [ 178.503467] ); [ 178.503716] lock( [ 178.504001] "nvme-wq" [ 178.504353] ); [ 178.504601] *** DEADLOCK *** [ 178.505441] May be due to missing lock nesting notation [ 178.506453] 2 locks held by kworker/5:1/135: [ 178.507068] #0: [ 178.507330] ( [ 178.507598] "nvme-wq" [ 178.507726] ){++++.+} [ 178.508079] , at: [ 178.508173] [<ffffffffa70ad6c2>] process_one_work+0x162/0x6a0 [ 178.509004] #1: [ 178.509265] ( [ 178.509532] (&ctrl->delete_work) [ 178.509795] ){+.+.+.} [ 178.510145] , at: [ 178.510239] [<ffffffffa70ad6c2>] process_one_work+0x162/0x6a0 [ 178.511070] stack backtrace: : [ 178.511693] CPU: 5 PID: 135 Comm: kworker/5:1 Tainted: G OE 4.9.0-rc4-c844263313a8-lb #3 [ 178.512974] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-1ubuntu1 04/01/2014 [ 178.514247] Workqueue: nvme-wq nvme_del_ctrl_work [nvme_tcp] [ 178.515071] ffffc2668175bae0 ffffffffa7450823 ffffffffa88abd80 ffffffffa88abd80 [ 178.516195] ffffc2668175bb98 ffffffffa70eb012 ffffffffa8d8d90d ffff9c472e9ea700 [ 178.517318] ffff9c472e9ea700 ffff9c4700000000 ffff9c4700007200 ab83be61bec0d50e [ 178.518443] Call Trace: [ 178.518807] [<ffffffffa7450823>] dump_stack+0x85/0xc2 [ 178.519542] [<ffffffffa70eb012>] __lock_acquire+0x17d2/0x18f0 [ 178.520377] [<ffffffffa75839a7>] ? serial8250_console_putchar+0x27/0x30 [ 178.521330] [<ffffffffa7583980>] ? wait_for_xmitr+0xa0/0xa0 [ 178.522174] [<ffffffffa70ac1eb>] ? flush_work+0x18b/0x2d0 [ 178.522975] [<ffffffffa70eb7cb>] lock_acquire+0x11b/0x220 [ 178.523753] [<ffffffffa70ac206>] ? flush_work+0x1a6/0x2d0 [ 178.524535] [<ffffffffa70ac229>] flush_work+0x1c9/0x2d0 [ 178.525291] [<ffffffffa70ac206>] ? flush_work+0x1a6/0x2d0 [ 178.526077] [<ffffffffa70a9cf0>] ? flush_workqueue_prep_pwqs+0x220/0x220 [ 178.527040] [<ffffffffa70ae7cf>] __cancel_work_timer+0x10f/0x1d0 [ 178.527907] [<ffffffffa70fecb9>] ? vprintk_default+0x29/0x40 [ 178.528726] [<ffffffffa71cb507>] ? printk+0x48/0x50 [ 178.529434] [<ffffffffa70ae8c3>] cancel_delayed_work_sync+0x13/0x20 [ 178.530381] [<ffffffffc042100b>] nvme_stop_ctrl+0x5b/0x70 [nvme_core] [ 178.531314] [<ffffffffc0403dcc>] nvme_del_ctrl_work+0x2c/0x50 [nvme_tcp] [ 178.532271] [<ffffffffa70ad741>] process_one_work+0x1e1/0x6a0 [ 178.533101] [<ffffffffa70ad6c2>] ? process_one_work+0x162/0x6a0 [ 178.533954] [<ffffffffa70adc4e>] worker_thread+0x4e/0x490 [ 178.534735] [<ffffffffa70adc00>] ? process_one_work+0x6a0/0x6a0 [ 178.535588] [<ffffffffa70adc00>] ? process_one_work+0x6a0/0x6a0 [ 178.536441] [<ffffffffa70b48cf>] kthread+0xff/0x120 [ 178.537149] [<ffffffffa70b47d0>] ? kthread_park+0x60/0x60 [ 178.538094] [<ffffffffa70b47d0>] ? kthread_park+0x60/0x60 [ 178.538900] [<ffffffffa78e332a>] ret_from_fork+0x2a/0x40 Signed-off-by:Roy Shterman <roys@lightbitslabs.com> Signed-off-by:
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Mike Snitzer authored
DM is no longer prone to having its request_queue be improperly initialized. Summary of changes: - defer DM's blk_register_queue() from add_disk()-time until dm_setup_md_queue() by using add_disk_no_queue_reg() in alloc_dev(). - dm_setup_md_queue() is updated to fully initialize DM's request_queue (_after_ all table loads have occurred and the request_queue's type, features and limits are known). A very welcome side-effect of these changes is DM no longer needs to: 1) backfill the "mq" sysfs entry (because historically DM didn't initialize the request_queue to use blk-mq until _after_ blk_register_queue() was called via add_disk()). 2) call elv_register_queue() to get .request_fn request-based DM device's "iosched" exposed in syfs. In addition, blk-mq debugfs support is now made available because request-based DM's blk-mq request_queue is now properly initialized before dm_setup_md_queue() calls blk_register_queue(). These changes also stave off the need to introduce new DM-specific workarounds in block core, e.g. this proposal: https://patchwork.kernel.org/patch/10067961/ In the end DM devices should be less unicorn in nature (relative to initialization and availability of block core infrastructure provided by the request_queue). Signed-off-by:
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Douglas Gilbert authored
During stress tests by syzkaller on the sg driver the block layer infrequently returns EINVAL. Closer inspection shows the block layer was trying to return ENOMEM (which is much more understandable) but for some reason overroad that useful error. Patch below does not show this (unchanged) line: ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy); That 'ret' was being overridden when that function failed. Signed-off-by:
Douglas Gilbert <dgilbert@interlog.com> Signed-off-by:
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Mike Snitzer authored
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:
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Mike Snitzer authored
The original commit e9a823fb (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: e9a823fb ("block: fix warning when I/O elevator is changed as request_queue is being removed") Signed-off-by:
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Mike Snitzer authored
device_add_disk() will only call bdi_register_owner() if !GENHD_FL_HIDDEN, so it follows that del_gendisk() should only call bdi_unregister() if !GENHD_FL_HIDDEN. Found with code inspection. bdi_unregister() won't do any harm if bdi_register_owner() wasn't used but best to avoid the unnecessary call to bdi_unregister(). Fixes: 8ddcd653 ("block: introduce GENHD_FL_HIDDEN") Signed-off-by:
Hannes Reinecke <hare@suse.com> Signed-off-by:
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