kernel/linux.git/drivers/nvme/host/core.c, branch v6.4

nvme: improve handling of long keep alives

2023-05-31T03:57:42+00:00

Upon keep alive completion, nvme_keep_alive_work is scheduled with the same delay every time. If keep alive commands are completing slowly, this may cause a keep alive timeout. The following trace illustrates the issue, taking KATO = 8 and TBKAS off for simplicity: 1. t = 0: run nvme_keep_alive_work, send keep alive 2. t = ε: keep alive reaches controller, controller restarts its keep alive timer 3. t = 4: host receives keep alive completion, schedules nvme_keep_alive_work with delay 4 4. t = 8: run nvme_keep_alive_work, send keep alive Here, a keep alive having RTT of 4 causes a delay of at least 8 - ε between the controller receiving successive keep alives. With ε small, the controller is likely to detect a keep alive timeout. Fix this by calculating the RTT of the keep alive command, and adjusting the scheduling delay of the next keep alive work accordingly. Reported-by: Costa Sapuntzakis Reported-by: Randy Jennings Signed-off-by: Uday Shankar Reviewed-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch

nvme: check IO start time when deciding to defer KA

2023-05-30T16:20:47+00:00

When a command completes, we set a flag which will skip sending a keep alive at the next run of nvme_keep_alive_work when TBKAS is on. However, if the command was submitted long ago, it's possible that the controller may have also restarted its keep alive timer (as a result of receiving the command) long ago. The following trace demonstrates the issue, assuming TBKAS is on and KATO = 8 for simplicity: 1. t = 0: submit I/O commands A, B, C, D, E 2. t = 0.5: commands A, B, C, D, E reach controller, restart its keep alive timer 3. t = 1: A completes 4. t = 2: run nvme_keep_alive_work, see recent completion, do nothing 5. t = 3: B completes 6. t = 4: run nvme_keep_alive_work, see recent completion, do nothing 7. t = 5: C completes 8. t = 6: run nvme_keep_alive_work, see recent completion, do nothing 9. t = 7: D completes 10. t = 8: run nvme_keep_alive_work, see recent completion, do nothing 11. t = 9: E completes At this point, 8.5 seconds have passed without restarting the controller's keep alive timer, so the controller will detect a keep alive timeout. Fix this by checking the IO start time when deciding to defer sending a keep alive command. Only set comp_seen if the command started after the most recent run of nvme_keep_alive_work. With this change, the completions of B, C, and D will not set comp_seen and the run of nvme_keep_alive_work at t = 4 will send a keep alive. Reported-by: Costa Sapuntzakis Reported-by: Randy Jennings Signed-off-by: Uday Shankar Reviewed-by: Hannes Reinecke Reviewed-by: Sagi Grimberg Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch

nvme: double KA polling frequency to avoid KATO with TBKAS on

2023-05-30T16:20:44+00:00

With TBKAS on, the completion of one command can defer sending a keep alive for up to twice the delay between successive runs of nvme_keep_alive_work. The current delay of KATO / 2 thus makes it possible for one command to defer sending a keep alive for up to KATO, which can result in the controller detecting a KATO. The following trace demonstrates the issue, taking KATO = 8 for simplicity: 1. t = 0: run nvme_keep_alive_work, no keep-alive sent 2. t = ε: I/O completion seen, set comp_seen = true 3. t = 4: run nvme_keep_alive_work, see comp_seen == true, skip sending keep-alive, set comp_seen = false 4. t = 8: run nvme_keep_alive_work, see comp_seen == false, send a keep-alive command. Here, there is a delay of 8 - ε between receiving a command completion and sending the next command. With ε small, the controller is likely to detect a keep alive timeout. Fix this by running nvme_keep_alive_work with a delay of KATO / 4 whenever TBKAS is on. Going through the above trace now gives us a worst-case delay of 4 - ε, which is in line with the recommendation of sending a command every KATO / 2 in the NVMe specification. Reported-by: Costa Sapuntzakis Reported-by: Randy Jennings Signed-off-by: Uday Shankar Reviewed-by: Hannes Reinecke Reviewed-by: Sagi Grimberg Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch

nvme: fix miss command type check

2023-05-30T15:50:24+00:00

In the function nvme_passthru_end(), only the value of the command opcode is checked, without checking the command type (IO command or Admin command). When we send a Dataset Management command (The opcode of the Dataset Management command is the same as the Set Feature command), kernel thinks it is a set feature command, then sets the controller's keep alive interval, and calls nvme_keep_alive_work(). Signed-off-by: min15.li Reviewed-by: Kanchan Joshi Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch

Merge tag 'nvme-6.4-2023-05-18' of git://git.infradead.org/nvme into block-6.4

2023-05-19T01:46:42+00:00

Pull NVMe fixes from Keith: "nvme fixes for Linux 6.4 - More device quirks (Sagi, Hristo, Adrian, Daniel) - Controller delete race (Maurizo) - Multipath cleanup fix (Christoph)" * tag 'nvme-6.4-2023-05-18' of git://git.infradead.org/nvme: nvme-pci: Add quirk for Teamgroup MP33 SSD nvme: do not let the user delete a ctrl before a complete initialization nvme-multipath: don't call blk_mark_disk_dead in nvme_mpath_remove_disk nvme-pci: clamp max_hw_sectors based on DMA optimized limitation nvme-pci: add quirk for missing secondary temperature thresholds nvme-pci: add NVME_QUIRK_BOGUS_NID for HS-SSD-FUTURE 2048G

nvme: do not let the user delete a ctrl before a complete initialization

2023-05-17T14:36:17+00:00

If a userspace application performes a "delete_controller" command early during the ctrl initialization, the delete operation may race against the init code and the kernel will crash. nvme nvme5: Connect command failed: host path error nvme nvme5: failed to connect queue: 0 ret=880 PF: supervisor write access in kernel mode PF: error_code(0x0002) - not-present page blk_mq_quiesce_queue+0x18/0x90 nvme_tcp_delete_ctrl+0x24/0x40 [nvme_tcp] nvme_do_delete_ctrl+0x7f/0x8b [nvme_core] nvme_sysfs_delete.cold+0x8/0xd [nvme_core] kernfs_fop_write_iter+0x124/0x1b0 new_sync_write+0xff/0x190 vfs_write+0x1ef/0x280 Fix the crash by checking the NVME_CTRL_STARTED_ONCE bit; if it's not set it means that the nvme controller is still in the process of getting initialized and the kernel will return an -EBUSY error to userspace. Set the NVME_CTRL_STARTED_ONCE later in the nvme_start_ctrl() function, after the controller start operation is completed. Signed-off-by: Maurizio Lombardi Reviewed-by: Sagi Grimberg Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch

Merge tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2023-04-27T18:53:57+00:00

Pull driver core updates from Greg KH: "Here is the large set of driver core changes for 6.4-rc1. Once again, a busy development cycle, with lots of changes happening in the driver core in the quest to be able to move "struct bus" and "struct class" into read-only memory, a task now complete with these changes. This will make the future rust interactions with the driver core more "provably correct" as well as providing more obvious lifetime rules for all busses and classes in the kernel. The changes required for this did touch many individual classes and busses as many callbacks were changed to take const * parameters instead. All of these changes have been submitted to the various subsystem maintainers, giving them plenty of time to review, and most of them actually did so. Other than those changes, included in here are a small set of other things: - kobject logging improvements - cacheinfo improvements and updates - obligatory fw_devlink updates and fixes - documentation updates - device property cleanups and const * changes - firwmare loader dependency fixes. All of these have been in linux-next for a while with no reported problems" * tag 'driver-core-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (120 commits) device property: make device_property functions take const device * driver core: update comments in device_rename() driver core: Don't require dynamic_debug for initcall_debug probe timing firmware_loader: rework crypto dependencies firmware_loader: Strip off \n from customized path zram: fix up permission for the hot_add sysfs file cacheinfo: Add use_arch[|_cache]_info field/function arch_topology: Remove early cacheinfo error message if -ENOENT cacheinfo: Check cache properties are present in DT cacheinfo: Check sib_leaf in cache_leaves_are_shared() cacheinfo: Allow early level detection when DT/ACPI info is missing/broken cacheinfo: Add arm64 early level initializer implementation cacheinfo: Add arch specific early level initializer tty: make tty_class a static const structure driver core: class: remove struct class_interface * from callbacks driver core: class: mark the struct class in struct class_interface constant driver core: class: make class_register() take a const * driver core: class: mark class_release() as taking a const * driver core: remove incorrect comment for device_create* MIPS: vpe-cmp: remove module owner pointer from struct class usage. ...

Merge tag 'for-6.4/block-2023-04-21' of git://git.kernel.dk/linux

2023-04-26T19:52:58+00:00

Pull block updates from Jens Axboe: - drbd patches, bringing us closer to unifying the out-of-tree version and the in tree one (Andreas, Christoph) - support for auto-quiesce for the s390 dasd driver (Stefan) - MD pull request via Song: - md/bitmap: Optimal last page size (Jon Derrick) - Various raid10 fixes (Yu Kuai, Li Nan) - md: add error_handlers for raid0 and linear (Mariusz Tkaczyk) - NVMe pull request via Christoph: - Drop redundant pci_enable_pcie_error_reporting (Bjorn Helgaas) - Validate nvmet module parameters (Chaitanya Kulkarni) - Fence TCP socket on receive error (Chris Leech) - Fix async event trace event (Keith Busch) - Minor cleanups (Chaitanya Kulkarni, zhenwei pi) - Fix and cleanup nvmet Identify handling (Damien Le Moal, Christoph Hellwig) - Fix double blk_mq_complete_request race in the timeout handler (Lei Yin) - Fix irq locking in nvme-fcloop (Ming Lei) - Remove queue mapping helper for rdma devices (Sagi Grimberg) - use structured request attribute checks for nbd (Jakub) - fix blk-crypto race conditions between keyslot management (Eric) - add sed-opal support for reading read locking range attributes (Ondrej) - make fault injection configurable for null_blk (Akinobu) - clean up the request insertion API (Christoph) - clean up the queue running API (Christoph) - blkg config helper cleanups (Tejun) - lazy init support for blk-iolatency (Tejun) - various fixes and tweaks to ublk (Ming) - remove hybrid polling. It hasn't really been useful since we got async polled IO support, and these days we don't support sync polled IO at all (Keith) - misc fixes, cleanups, improvements (Zhong, Ondrej, Colin, Chengming, Chaitanya, me) * tag 'for-6.4/block-2023-04-21' of git://git.kernel.dk/linux: (118 commits) nbd: fix incomplete validation of ioctl arg ublk: don't return 0 in case of any failure sed-opal: geometry feature reporting command null_blk: Always check queue mode setting from configfs block: ublk: switch to ioctl command encoding blk-mq: fix the blk_mq_add_to_requeue_list call in blk_kick_flush block, bfq: Fix division by zero error on zero wsum fault-inject: fix build error when FAULT_INJECTION_CONFIGFS=y and CONFIGFS_FS=m block: store bdev->bd_disk->fops->submit_bio state in bdev block: re-arrange the struct block_device fields for better layout md/raid5: remove unused working_disks variable md/raid10: don't call bio_start_io_acct twice for bio which experienced read error md/raid10: fix memleak of md thread md/raid10: fix memleak for 'conf->bio_split' md/raid10: fix leak of 'r10bio->remaining' for recovery md/raid10: don't BUG_ON() in raise_barrier() md: fix soft lockup in status_resync md: add error_handlers for raid0 and linear md: Use optimal I/O size for last bitmap page md: Fix types in sb writer ...

nvme: fix double blk_mq_complete_request for timeout request with low probability

2023-04-13T06:59:04+00:00

When nvme_cancel_tagset traverses all tagsets and executes nvme_cancel_request, this request may be executing blk_mq_free_request that is called by nvme_rdma_complete_timed_out/nvme_tcp_complete_timed_out. When blk_mq_free_request executes to WRITE_ONCE(rq->state, MQ_RQ_IDLE) and __blk_mq_free_request(rq), it will cause double blk_mq_complete_request for this request, and it will cause a null pointer error in the second execution of this function because rq->mq_hctx has set to NULL in first execution. Signed-off-by: Lei Yin Reviewed-by: Keith Busch Reviewed-by: Sagi Grimberg Signed-off-by: Christoph Hellwig

nvme: fix async event trace event

2023-04-13T06:59:04+00:00

Mixing AER Event Type and Event Info has masking clashes. Just print the event type, but also include the event info of the AER result in the trace. Fixes: 09bd1ff4b15143b ("nvme-core: add async event trace helper") Reported-by: Nate Thornton Reviewed-by: Sagi Grimberg Reviewed-by: Minwoo Im Reviewed-by: Chaitanya Kulkarni Signed-off-by: Keith Busch Signed-off-by: Christoph Hellwig