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2018-05-30blk-throttle: return proper bool type to caller instead of 0/1Chengguang Xu
Change to return true/false only for bool type return code. Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30blk-mq: only iterate over inflight requests in blk_mq_tagset_busy_iterChristoph Hellwig
We already check for started commands in all callbacks, but we should also protect against already completed commands. Do this by taking the checks to common code. Acked-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30nbd: clear DISCONNECT_REQUESTED flag once disconnection occurs.Kevin Vigor
When a userspace client requests a NBD device be disconnected, the DISCONNECT_REQUESTED flag is set. While this flag is set, the driver will not inform userspace when a connection is closed. Unfortunately the flag was never cleared, so once a disconnect was requested the driver would thereafter never tell userspace about a closed connection. Thus when connections failed due to timeout, no attempt to reconnect was made and eventually the device would fail. Fix by clearing the DISCONNECT_REQUESTED flag (and setting the DISCONNECTED flag) once all connections are closed. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Kevin Vigor <kvigor@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30blk-throttle: fix potential NULL pointer dereference in throtl_select_dispatchLiu Bo
tg in throtl_select_dispatch is used first and then do check. Since tg may be NULL, it has potential NULL pointer dereference risk. So fix it. Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30block: kyber: make kyber more friendly with mergingJianchao Wang
Currently, kyber is very unfriendly with merging. kyber depends on ctx rq_list to do merging, however, most of time, it will not leave any requests in ctx rq_list. This is because even if tokens of one domain is used up, kyber will try to dispatch requests from other domain and flush the rq_list there. To improve this, we setup kyber_ctx_queue (kcq) which is similar with ctx, but it has rq_lists for different domain and build same mapping between kcq and khd as the ctx & hctx. Then we could merge, insert and dispatch for different domains separately. At the same time, only flush the rq_list of kcq when get domain token successfully. Then if one domain token is used up, the requests could be left in the rq_list of that domain and maybe merged with following io. Following is my test result on machine with 8 cores and NVMe card INTEL SSDPEKKR128G7 fio size=256m ioengine=libaio iodepth=64 direct=1 numjobs=8 seq/random +------+---------------------------------------------------------------+ |patch?| bw(MB/s) | iops | slat(usec) | clat(usec) | merge | +----------------------------------------------------------------------+ | w/o | 606/612 | 151k/153k | 6.89/7.03 | 3349.21/3305.40 | 0/0 | +----------------------------------------------------------------------+ | w/ | 1083/616 | 277k/154k | 4.93/6.95 | 1830.62/3279.95 | 223k/3k | +----------------------------------------------------------------------+ When set numjobs to 16, the bw and iops could reach 1662MB/s and 425k on my platform. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-30blk-mq: abstract out blk-mq-sched rq list iteration bio merge helperJens Axboe
No functional changes in this patch, just a prep patch for utilizing this in an IO scheduler. Signed-off-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Omar Sandoval <osandov@fb.com>
2018-05-29block: remove parent device reference from struct bsg_class_deviceChristoph Hellwig
Bsg holding a reference to the parent device may result in a crash if a bsg file handle is closed after the parent device driver has unloaded. Holding a reference is not really needed: the parent device must exist between bsg_register_queue and bsg_unregister_queue. Before the device goes away the caller does blk_cleanup_queue so that all in-flight requests to the device are gone and all new requests cannot pass beyond the queue. The queue itself is a refcounted object and it will stay alive with a bsg file. Based on analysis, previous patch and changelog from Anatoliy Glagolev. Reported-by: Anatoliy Glagolev <glagolig@gmail.com> Reviewed-by: James E.J. Bottomley <jejb@linux.vnet.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29Merge branch 'nvme-4.18-2' of git://git.infradead.org/nvme into for-4.18/blockJens Axboe
Pull NVMe changes from Christoph: "Here is the current batch of nvme updates for 4.18, we have a few more patches in the queue, but I'd like to get this pile into your tree and linux-next ASAP. The biggest item is support for file-backed namespaces in the NVMe target from Chaitanya, in addition to that we mostly small fixes from all the usual suspects." * 'nvme-4.18-2' of git://git.infradead.org/nvme: nvme: fixup memory leak in nvme_init_identify() nvme: fix KASAN warning when parsing host nqn nvmet-loop: use nr_phys_segments when map rq to sgl nvmet-fc: increase LS buffer count per fc port nvmet: add simple file backed ns support nvmet: remove duplicate NULL initialization for req->ns nvmet: make a few error messages more generic nvme-fabrics: allow duplicate connections to the discovery controller nvme-fabrics: centralize discovery controller defaults nvme-fabrics: remove unnecessary controller subnqn validation nvme-fc: remove setting DNR on exception conditions nvme-rdma: stop admin queue before freeing it nvme-pci: Fix AER reset handling nvme-pci: set nvmeq->cq_vector after alloc cq/sq nvme: host: core: fix precedence of ternary operator nvme: fix lockdep warning in nvme_mpath_clear_current_path
2018-05-29block: don't print a message when the device went awayChristoph Hellwig
The information about a size change in this case just creates confusion. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29block: unexport check_disk_size_changeChristoph Hellwig
Only used in block_dev.c and the partitions code, and it should remain that way.. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29block: move ->timeout request memberJens Axboe
After the recent timeout handling changes, we have two holes in the struct. Move the timeout near the deadline, killing both, and moving related members closer together. On my config on x86-64, this shrinks struct request from 312 to 304 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29blk-mq: simplify blk_mq_rq_timed_outChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29block: document the blk_eh_timer_return valuesChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29block: remove BLK_EH_HANDLEDChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29libiscsi: don't try to bypass SCSI EHChristoph Hellwig
libiscsi is the only SCSI code that return BLK_EH_HANDLED, thus trying to bypass the normal SCSI EH code. We are going to remove this return value at the block layer, and at least from a quick look it doesn't look too harmful to try to send an abort for these cases, especially as the first one should not actually be possible. If this doesn't work out iscsi will probably need its own eh_strategy_handler instead to just do the right thing. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29mmc: complete requests from ->timeoutChristoph Hellwig
By completing the request entirely in the driver we can remove the BLK_EH_HANDLED return value and thus the split responsibility between the driver and the block layer that has been causing trouble. [While this keeps existing behavior it seems to mismatch the comment, maintainers please chime in!] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29scsi_transport_fc: complete requests from ->timeoutChristoph Hellwig
By completing the request entirely in the driver we can remove the BLK_EH_HANDLED return value and thus the split responsibility between the driver and the block layer that has been causing trouble. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29null_blk: complete requests from ->timeoutChristoph Hellwig
By completing the request entirely in the driver we can remove the BLK_EH_HANDLED return value and thus the split responsibility between the driver and the block layer that has been causing trouble. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29mtip32xx: complete requests from ->timeoutChristoph Hellwig
By completing the request entirely in the driver we can remove the BLK_EH_HANDLED return value and thus the split responsibility between the driver and the block layer that has been causing trouble. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29nbd: complete requests from ->timeoutChristoph Hellwig
By completing the request entirely in the driver we can remove the BLK_EH_HANDLED return value and thus the split responsibility between the driver and the block layer that has been causing trouble. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29nvme: return BLK_EH_DONE from ->timeoutChristoph Hellwig
NVMe always completes the request before returning from ->timeout, either by polling for it, or by disabling the controller. Return BLK_EH_DONE so that the block layer doesn't even try to complete it again. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29block: rename BLK_EH_NOT_HANDLED to BLK_EH_DONEChristoph Hellwig
The BLK_EH_NOT_HANDLED implies nothing happen, but very often that is not what is happening - instead the driver already completed the command. Fix the symbolic name to reflect that a little better. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29blk-mq: Remove generation seqeunceKeith Busch
This patch simplifies the timeout handling by relying on the request reference counting to ensure the iterator is operating on an inflight and truly timed out request. Since the reference counting prevents the tag from being reallocated, the block layer no longer needs to prevent drivers from completing their requests while the timeout handler is operating on it: a driver completing a request is allowed to proceed to the next state without additional syncronization with the block layer. This also removes any need for generation sequence numbers since the request lifetime is prevented from being reallocated as a new sequence while timeout handling is operating on it. To enables this a refcount is added to struct request so that request users can be sure they're operating on the same request without it changing while they're processing it. The request's tag won't be released for reuse until both the timeout handler and the completion are done with it. Signed-off-by: Keith Busch <keith.busch@intel.com> [hch: slight cleanups, added back submission side hctx lock, use cmpxchg for completions] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29blk-mq: Fix timeout and state orderKeith Busch
The block layer had been setting the state to in-flight prior to updating the timer. This is the wrong order since the timeout handler could observe the in-flight state with the older timeout, believing the request had expired when in fact it is just getting started. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-29libata: remove ata_scsi_timed_outChristoph Hellwig
As far as I can tell this function can't even be called any more, given that ATA implements its own eh_strategy_handler with ata_scsi_error, which never calls ->eh_timed_out. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-28bcache: Replace bch_read_string_list() by __sysfs_match_string()Andy Shevchenko
Kernel library has a common function to match user input from sysfs against an array of strings. Thus, replace bch_read_string_list() by __sysfs_match_string(). Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-28bcache: Move couple of functions to sysfs.cAndy Shevchenko
There is couple of functions that are used exclusively in sysfs.c. Move it to there and make them static. Besides above, it will allow further clean up. No functional change intended. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-28bcache: Move couple of string arrays to sysfs.cAndy Shevchenko
There is couple of string arrays that are used exclusively in sysfs.c. Move it to there and make them static. Besides above, it will allow further clean up. No functional change intended. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-28bcache: stop bcache device when backing device is offlineColy Li
Currently bcache does not handle backing device failure, if backing device is offline and disconnected from system, its bcache device can still be accessible. If the bcache device is in writeback mode, I/O requests even can success if the requests hit on cache device. That is to say, when and how bcache handles offline backing device is undefined. This patch tries to handle backing device offline in a rather simple way, - Add cached_dev->status_update_thread kernel thread to update backing device status in every 1 second. - Add cached_dev->offline_seconds to record how many seconds the backing device is observed to be offline. If the backing device is offline for BACKING_DEV_OFFLINE_TIMEOUT (30) seconds, set dc->io_disable to 1 and call bcache_device_stop() to stop the bache device which linked to the offline backing device. Now if a backing device is offline for BACKING_DEV_OFFLINE_TIMEOUT seconds, its bcache device will be removed, then user space application writing on it will get error immediately, and handler the device failure in time. This patch is quite simple, does not handle more complicated situations. Once the bcache device is stopped, users need to recovery the backing device, register and attach it manually. Changelog: v3: call wait_for_kthread_stop() before exits kernel thread. v2: remove "bcache: " prefix when calling pr_warn(). v1: initial version. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Junhui Tang <tang.junhui@zte.com.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-25null_blk: add blocking description and remove lightnvmLiu Bo
- The description of 'blocking' is missing in null_blk.txt - The 'lightnvm' parameter has been removed in null_blk.c This updates both in null_blk.txt. Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-25nvme: fixup memory leak in nvme_init_identify()Hannes Reinecke
If nvme_get_effects_log() failed the 'id' buffer from the previous nvme_identify_ctrl() call will never be freed. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme: fix KASAN warning when parsing host nqnHannes Reinecke
The host nqn actually is smaller than the space reserved for it, so we should be using strlcpy to keep KASAN happy. Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvmet-loop: use nr_phys_segments when map rq to sglChaitanya Kulkarni
Use blk_rq_nr_phys_segments() instead of blk_rq_payload_bytes() to check if a command contains data to me mapped. This fixes the case where a struct requests contains LBAs, but no data will actually be send, e.g. the pending Write Zeroes support. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvmet-fc: increase LS buffer count per fc portJames Smart
Todays limit on concurrent LS's is very small - 4 buffers. With large subsystem counts or large numbers of initiators connecting, the limit may be exceeded. Raise the LS buffer count to 256. Signed-off-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvmet: add simple file backed ns supportChaitanya Kulkarni
This patch adds simple file backed namespace support for NVMeOF target. The new file io-cmd-file.c is responsible for handling the code for I/O commands when ns is file backed. Also, we introduce mempools based slow path using sync I/Os for file backed ns to ensure forward progress under reclaim. The old block device based implementation is moved to io-cmd-bdev.c and use a "nvmet_bdev_" symbol prefix. The enable/disable calls are also move into the respective files. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> [hch: updated changelog, fixed double req->ns lookup in bdev case] Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvmet: remove duplicate NULL initialization for req->nsChaitanya Kulkarni
Remove the duplicate NULL initialization for req->ns. req->ns is always initialized to NULL in nvmet_req_init(), so there is no need to reset it later on failures unless we have previously assigned a value to it. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvmet: make a few error messages more genericChaitanya Kulkarni
"nvmet_check_ctrl_status()" is called from admin-cmd.c along with io-cmd.c, make the error message more generic. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme-fabrics: allow duplicate connections to the discovery controllerHannes Reinecke
The whole point of the discovery controller is that it can accept multiple connections. Additionally the cmic field is not even defined for the discovery controller identify page. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme-fabrics: centralize discovery controller defaultsHannes Reinecke
When connecting to the discovery controller we have certain defaults to observe, so centralize them to avoid inconsistencies due to argument ordering. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: James Smart <james.smart@broadcom.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme-fabrics: remove unnecessary controller subnqn validationJames Smart
After creating the nvme controller, nvmf_create_ctrl() validates the newly created subsysnqn vs the one specified by the options. In general, this is an unnecessary check as the Connect message should implicitly ensure this value matches. With the change to the FC transport to do an asynchronous connect for the first association create, the transport will return to nvmf_create_ctrl() before that first association has been established, thus the subnqn will not yet be set. Remove the unnecessary validation. Signed-off-by: James Smart <james.smart@broadcom.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme-fc: remove setting DNR on exception conditionsJames Smart
Current code will set DNR if the controller is deleting or there is an error during controller init. None of this is necessary. Remove the code that sets DNR Signed-off-by: James Smart <james.smart@broadcom.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme-rdma: stop admin queue before freeing itJianchao Wang
For any failure after nvme_rdma_start_queue in nvme_rdma_configure_admin_queue, the admin queue will be freed with the NVME_RDMA_Q_LIVE flag still set. Once nvme_rdma_stop_queue is invoked, that will cause a use-after-free. BUG: KASAN: use-after-free in rdma_disconnect+0x1f/0xe0 [rdma_cm] To fix it, call nvme_rdma_stop_queue for all the failed cases after nvme_rdma_start_queue. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Suggested-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme-pci: Fix AER reset handlingKeith Busch
The nvme timeout handling doesn't do anything if the pci channel is offline, which is the case when recovering from PCI error event, so it was a bad idea to sync the controller reset in this state. This patch flushes the reset work in the error_resume callback instead when the channel is back to online. This keeps AER handling serialized and can recover from timeouts. Link: https://bugzilla.kernel.org/show_bug.cgi?id=199757 Fixes: cc1d5e749a2e ("nvme/pci: Sync controller reset for AER slot_reset") Reported-by: Alex Gagniuc <mr.nuke.me@gmail.com> Tested-by: Alex Gagniuc <mr.nuke.me@gmail.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-25nvme-pci: set nvmeq->cq_vector after alloc cq/sqJianchao Wang
Set cq_vector after alloc cq/sq, otherwise nvme_suspend_queue will invoke free_irq for it and cause a 'Trying to free already-free IRQ xxx' warning if the create CQ/SQ command times out. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Reviewed-by: Keith Busch <keith.busch@intel.com> [hch: fixed to pass a s16 and clean up the comment] Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-24block drivers/block: Use octal not symbolic permissionsJoe Perches
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>
2018-05-24blk-mq: avoid starving tag allocation after allocating process migratesMing Lei
When the allocation process is scheduled back and the mapped hw queue is changed, fake one extra wake up on previous queue for compensating wake up miss, so other allocations on the previous queue won't be starved. This patch fixes one request allocation hang issue, which can be triggered easily in case of very low nr_request. The race is as follows: 1) 2 hw queues, nr_requests are 2, and wake_batch is one 2) there are 3 waiters on hw queue 0 3) two in-flight requests in hw queue 0 are completed, and only two waiters of 3 are waken up because of wake_batch, but both the two waiters can be scheduled to another CPU and cause to switch to hw queue 1 4) then the 3rd waiter will wait for ever, since no in-flight request is in hw queue 0 any more. 5) this patch fixes it by the fake wakeup when waiter is scheduled to another hw queue Cc: <stable@vger.kernel.org> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Modified commit message to make it clearer, and make it apply on top of the 4.18 branch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-23bdi: Move cgroup bdi_writeback to a dedicated low concurrency workqueueTejun Heo
From 0aa2e9b921d6db71150633ff290199554f0842a8 Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj@kernel.org> Date: Wed, 23 May 2018 10:29:00 -0700 cgwb_release() punts the actual release to cgwb_release_workfn() on system_wq. Depending on the number of cgroups or block devices, there can be a lot of cgwb_release_workfn() in flight at the same time. We're periodically seeing close to 256 kworkers getting stuck with the following stack trace and overtime the entire system gets stuck. [<ffffffff810ee40c>] _synchronize_rcu_expedited.constprop.72+0x2fc/0x330 [<ffffffff810ee634>] synchronize_rcu_expedited+0x24/0x30 [<ffffffff811ccf23>] bdi_unregister+0x53/0x290 [<ffffffff811cd1e9>] release_bdi+0x89/0xc0 [<ffffffff811cd645>] wb_exit+0x85/0xa0 [<ffffffff811cdc84>] cgwb_release_workfn+0x54/0xb0 [<ffffffff810a68d0>] process_one_work+0x150/0x410 [<ffffffff810a71fd>] worker_thread+0x6d/0x520 [<ffffffff810ad3dc>] kthread+0x12c/0x160 [<ffffffff81969019>] ret_from_fork+0x29/0x40 [<ffffffffffffffff>] 0xffffffffffffffff The events leading to the lockup are... 1. A lot of cgwb_release_workfn() is queued at the same time and all system_wq kworkers are assigned to execute them. 2. They all end up calling synchronize_rcu_expedited(). One of them wins and tries to perform the expedited synchronization. 3. However, that invovles queueing rcu_exp_work to system_wq and waiting for it. Because #1 is holding all available kworkers on system_wq, rcu_exp_work can't be executed. cgwb_release_workfn() is waiting for synchronize_rcu_expedited() which in turn is waiting for cgwb_release_workfn() to free up some of the kworkers. We shouldn't be scheduling hundreds of cgwb_release_workfn() at the same time. There's nothing to be gained from that. This patch updates cgwb release path to use a dedicated percpu workqueue with @max_active of 1. While this resolves the problem at hand, it might be a good idea to isolate rcu_exp_work to its own workqueue too as it can be used from various paths and is prone to this sort of indirect A-A deadlocks. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-23nbd: set discard granularity properlyJosef Bacik
For some reason we had discard granularity set to 512 always even when discards were disabled. Fix this by having the default be 0, and then if we turn it on set the discard granularity to the blocksize. Signed-off-by: Josef Bacik <jbacik@fb.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-23nvme: host: core: fix precedence of ternary operatorIvan Bornyakov
Ternary operator have lower precedence then bitwise or, so 'cdw10' was calculated wrong. Signed-off-by: Ivan Bornyakov <brnkv.i1@gmail.com> Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Signed-off-by: Keith Busch <keith.busch@intel.com>
2018-05-23nvme: fix lockdep warning in nvme_mpath_clear_current_pathJohannes Thumshirn
When running blktest's nvme/005 with a lockdep enabled kernel the test case fails due to the following lockdep splat in dmesg: ============================= WARNING: suspicious RCU usage 4.17.0-rc5 #881 Not tainted ----------------------------- drivers/nvme/host/nvme.h:457 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 3 locks held by kworker/u32:5/1102: #0: (ptrval) ((wq_completion)"nvme-wq"){+.+.}, at: process_one_work+0x152/0x5c0 #1: (ptrval) ((work_completion)(&ctrl->scan_work)){+.+.}, at: process_one_work+0x152/0x5c0 #2: (ptrval) (&subsys->lock#2){+.+.}, at: nvme_ns_remove+0x43/0x1c0 [nvme_core] The only caller of nvme_mpath_clear_current_path() is nvme_ns_remove() which holds the subsys lock so it's likely a false positive, but when using rcu_access_pointer(), we're telling rcu and lockdep that we're only after the pointer falue. Fixes: 32acab3181c7 ("nvme: implement multipath access to nvme subsystems") Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <keith.busch@intel.com>