kernel/linux.git/drivers/nvme/host/fc.c, branch linux-4.16.y

nvme_fc: fix abort race on teardown with lld reject

2018-05-30T06:17:29+00:00

[ Upstream commit b12740d316fa89f3f6191b71f986cf3b9383d379 ] Another abort race: An io request is started, becomes active, and is attempted to be started with the lldd. At the same time the controller is stopped/torndown and an itterator is run to abort the ios. As the io is active, it is added to the outstanding aborted io count. However on the original io request thread, the driver ends up rejecting the io due to the condition that induced the controller teardown. The driver reject path didn't check whether it was in the outstanding io count. This left the count outstanding stopping controller teardown. Correct by, in the driver reject case, setting the state to inactive and checking whether it was in the outstanding io count. Signed-off-by: James Smart Reviewed-by: Sagi Grimberg Signed-off-by: Keith Busch Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nvme: expand nvmf_check_if_ready checks

2018-05-30T06:17:20+00:00

[ Upstream commit bb06ec31452fb2da1594f88035c2ecea4e0652f4 ] The nvmf_check_if_ready() checks that were added are very simplistic. As such, the routine allows a lot of cases to fail ios during windows of reset or re-connection. In cases where there are not multi-path options present, the error goes back to the callee - the filesystem or application. Not good. The common routine was rewritten and calling syntax slightly expanded so that per-transport is_ready routines don't need to be present. The transports now call the routine directly. The routine is now a fabrics routine rather than an inline function. The routine now looks at controller state to decide the action to take. Some states mandate io failure. Others define the condition where a command can be accepted. When the decision is unclear, a generic queue-or-reject check is made to look for failfast or multipath ios and only fails the io if it is so marked. Otherwise, the io will be queued and wait for the controller state to resolve. Admin commands issued via ioctl share a live admin queue with commands from the transport for controller init. The ioctls could be intermixed with the initialization commands. It's possible for the ioctl cmd to be issued prior to the controller being enabled. To block this, the ioctl admin commands need to be distinguished from admin commands used for controller init. Added a USERCMD nvme_req(req)->rq_flags bit to reflect this division and set it on ioctls requests. As the nvmf_check_if_ready() routine is called prior to nvme_setup_cmd(), ensure that commands allocated by the ioctl path (actually anything in core.c) preps the nvme_req(req) before starting the io. This will preserve the USERCMD flag during execution and/or retry. Signed-off-by: James Smart Reviewed-by: Sagi Grimberg Reviewed-by: Johannes Thumshirn Signed-off-by: Keith Busch Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nvme_fc: rework sqsize handling

2018-03-08T17:39:58+00:00

Corrected four outstanding issues in the transport around sqsize. 1: Create Connection LS is sending the 1's-based sqsize, should be sending the 0's-based value. 2: allocation of hw queue is using the 0's-base size. It should be using the 1's-based value. 3: normalization of ctrl.sqsize by MQES is using MQES+1 (1's-based value). It should be MQES (0's-based value). 4: Missing clause to ensure queue_count not larger than ctrl->sqsize. Corrected by: Clean up routines that pass queue size around. The queue size value is the actual count (1's-based) value and determined from ctrl->sqsize + 1. Routines that send 0's-based value adapt from queue size. Sset ctrl->sqsize properly for MQES. Added clause to nsure queue_count not larger than ctrl->sqsize + 1. Signed-off-by: James Smart Reviewed-by: Sagi Grimberg Signed-off-by: Keith Busch

nvme_fc: cleanup io completion

2018-02-11T08:45:43+00:00

There was some old cold that dealt with complete_rq being called prior to the lldd returning the io completion. This is garbage code. The complete_rq routine was being called after eh_timeouts were called and it was due to eh_timeouts not being handled properly. The timeouts were fixed in prior patches so that in general, a timeout will initiate an abort and the reset timer restarted as the abort operation will take care of completing things. Given the reset timer restarted, the erroneous complete_rq calls were eliminated. So remove the work that was synchronizing complete_rq with io completion. Reviewed-by: Johannes Thumshirn Signed-off-by: James Smart Signed-off-by: Sagi Grimberg

nvme_fc: correct abort race condition on resets

2018-02-11T08:45:34+00:00

During reset handling, there is live io completing while the reset is taking place. The reset path attempts to abort all outstanding io, counting the number of ios that were reset. It then waits for those ios to be reclaimed from the lldd before continuing. The transport's logic on io state and flag setting was poor, allowing ios to complete simultaneous to the abort request. The completed ios were counted, but as the completion had already occurred, the completion never reduced the count. As the count never zeros, the reset/delete never completes. Tighten it up by unconditionally changing the op state to completed when the io done handler is called. The reset/abort path now changes the op state to aborted, but the abort only continues if the op state was live priviously. If complete, the abort is backed out. Thus proper counting of io aborts and their completions is working again. Also removed the TERMIO state on the op as it's redundant with the op's aborted state. Reviewed-by: Johannes Thumshirn Signed-off-by: James Smart Signed-off-by: Sagi Grimberg

nvme: rename NVME_CTRL_RECONNECTING state to NVME_CTRL_CONNECTING

2018-02-08T16:35:53+00:00

In pci transport, this state is used to mark the initialization process. This should be also used in other transports as well. Signed-off-by: Max Gurtovoy Reviewed-by: James Smart Signed-off-by: Sagi Grimberg

blk-mq: introduce BLK_STS_DEV_RESOURCE

2018-01-31T03:18:28+00:00

This status is returned from driver to block layer if device related resource is unavailable, but driver can guarantee that IO dispatch will be triggered in future when the resource is available. Convert some drivers to return BLK_STS_DEV_RESOURCE. Also, if driver returns BLK_STS_RESOURCE and SCHED_RESTART is set, rerun queue after a delay (BLK_MQ_DELAY_QUEUE) to avoid IO stalls. BLK_MQ_DELAY_QUEUE is 3 ms because both scsi-mq and nvmefc are using that magic value. If a driver can make sure there is in-flight IO, it is safe to return BLK_STS_DEV_RESOURCE because: 1) If all in-flight IOs complete before examining SCHED_RESTART in blk_mq_dispatch_rq_list(), SCHED_RESTART must be cleared, so queue is run immediately in this case by blk_mq_dispatch_rq_list(); 2) if there is any in-flight IO after/when examining SCHED_RESTART in blk_mq_dispatch_rq_list(): - if SCHED_RESTART isn't set, queue is run immediately as handled in 1) - otherwise, this request will be dispatched after any in-flight IO is completed via blk_mq_sched_restart() 3) if SCHED_RESTART is set concurently in context because of BLK_STS_RESOURCE, blk_mq_delay_run_hw_queue() will cover the above two cases and make sure IO hang can be avoided. One invariant is that queue will be rerun if SCHED_RESTART is set. Suggested-by: Jens Axboe Tested-by: Laurence Oberman Signed-off-by: Ming Lei Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe

Merge branch 'for-4.16/block' of git://git.kernel.dk/linux-block

2018-01-29T19:51:49+00:00

Pull block updates from Jens Axboe: "This is the main pull request for block IO related changes for the 4.16 kernel. Nothing major in this pull request, but a good amount of improvements and fixes all over the map. This contains: - BFQ improvements, fixes, and cleanups from Angelo, Chiara, and Paolo. - Support for SMR zones for deadline and mq-deadline from Damien and Christoph. - Set of fixes for bcache by way of Michael Lyle, including fixes from himself, Kent, Rui, Tang, and Coly. - Series from Matias for lightnvm with fixes from Hans Holmberg, Javier, and Matias. Mostly centered around pblk, and the removing rrpc 1.2 in preparation for supporting 2.0. - A couple of NVMe pull requests from Christoph. Nothing major in here, just fixes and cleanups, and support for command tracing from Johannes. - Support for blk-throttle for tracking reads and writes separately. From Joseph Qi. A few cleanups/fixes also for blk-throttle from Weiping. - Series from Mike Snitzer that enables dm to register its queue more logically, something that's alwways been problematic on dm since it's a stacked device. - Series from Ming cleaning up some of the bio accessor use, in preparation for supporting multipage bvecs. - Various fixes from Ming closing up holes around queue mapping and quiescing. - BSD partition fix from Richard Narron, fixing a problem where we can't mount newer (10/11) FreeBSD partitions. - Series from Tejun reworking blk-mq timeout handling. The previous scheme relied on atomic bits, but it had races where we would think a request had timed out if it to reused at the wrong time. - null_blk now supports faking timeouts, to enable us to better exercise and test that functionality separately. From me. - Kill the separate atomic poll bit in the request struct. After this, we don't use the atomic bits on blk-mq anymore at all. From me. - sgl_alloc/free helpers from Bart. - Heavily contended tag case scalability improvement from me. - Various little fixes and cleanups from Arnd, Bart, Corentin, Douglas, Eryu, Goldwyn, and myself" * 'for-4.16/block' of git://git.kernel.dk/linux-block: (186 commits) block: remove smart1,2.h nvme: add tracepoint for nvme_complete_rq nvme: add tracepoint for nvme_setup_cmd nvme-pci: introduce RECONNECTING state to mark initializing procedure nvme-rdma: remove redundant boolean for inline_data nvme: don't free uuid pointer before printing it nvme-pci: Suspend queues after deleting them bsg: use pr_debug instead of hand crafted macros blk-mq-debugfs: don't allow write on attributes with seq_operations set nvme-pci: Fix queue double allocations block: Set BIO_TRACE_COMPLETION on new bio during split blk-throttle: use queue_is_rq_based block: Remove kblockd_schedule_delayed_work{,_on}() blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces unintended delays blk-mq: Rename blk_mq_request_direct_issue() into blk_mq_request_issue_directly() lib/scatterlist: Fix chaining support in sgl_alloc_order() blk-throttle: track read and write request individually block: add bdev_read_only() checks to common helpers block: fail op_is_write() requests to read-only partitions blk-throttle: export io_serviced_recursive, io_service_bytes_recursive ...

nvme-fc: correct hang in nvme_ns_remove()

2018-01-17T16:55:02+00:00

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 Signed-off-by: Christoph Hellwig

nvme-fc: fix rogue admin cmds stalling teardown

2018-01-17T16:54:49+00:00

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: James Smart Signed-off-by: Christoph Hellwig