aboutsummaryrefslogtreecommitdiffstats
path: root/block (follow)
AgeCommit message (Collapse)AuthorFilesLines
2017-09-25block: fix a crash caused by wrong APIShaohua Li1-1/+1
part_stat_show takes a part device not a disk, so we should use part_to_disk. Fixes: d62e26b3ffd2("block: pass in queue to inflight accounting") Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-25blktrace: Fix potential deadlock between delete & sysfs opsWaiman Long1-0/+3
The lockdep code had reported the following unsafe locking scenario: CPU0 CPU1 ---- ---- lock(s_active#228); lock(&bdev->bd_mutex/1); lock(s_active#228); lock(&bdev->bd_mutex); *** DEADLOCK *** The deadlock may happen when one task (CPU1) is trying to delete a partition in a block device and another task (CPU0) is accessing tracing sysfs file (e.g. /sys/block/dm-1/trace/act_mask) in that partition. The s_active isn't an actual lock. It is a reference count (kn->count) on the sysfs (kernfs) file. Removal of a sysfs file, however, require a wait until all the references are gone. The reference count is treated like a rwsem using lockdep instrumentation code. The fact that a thread is in the sysfs callback method or in the ioctl call means there is a reference to the opended sysfs or device file. That should prevent the underlying block structure from being removed. Instead of using bd_mutex in the block_device structure, a new blk_trace_mutex is now added to the request_queue structure to protect access to the blk_trace structure. Suggested-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Fix typo in patch subject line, and prune a comment detailing how the code used to work. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-25bsg-lib: don't free job in bsg_prepare_jobChristoph Hellwig1-1/+0
The job structure is allocated as part of the request, so we should not free it in the error path of bsg_prepare_job. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-11block: directly insert blk-mq request from blk_insert_cloned_request()Jens Axboe3-1/+23
A NULL pointer crash was reported for the case of having the BFQ IO scheduler attached to the underlying blk-mq paths of a DM multipath device. The crash occured in blk_mq_sched_insert_request()'s call to e->type->ops.mq.insert_requests(). Paolo Valente correctly summarized why the crash occured with: "the call chain (dm_mq_queue_rq -> map_request -> setup_clone -> blk_rq_prep_clone) creates a cloned request without invoking e->type->ops.mq.prepare_request for the target elevator e. The cloned request is therefore not initialized for the scheduler, but it is however inserted into the scheduler by blk_mq_sched_insert_request." All said, a request-based DM multipath device's IO scheduler should be the only one used -- when the original requests are issued to the underlying paths as cloned requests they are inserted directly in the underlying dispatch queue(s) rather than through an additional elevator. But commit bd166ef18 ("blk-mq-sched: add framework for MQ capable IO schedulers") switched blk_insert_cloned_request() from using blk_mq_insert_request() to blk_mq_sched_insert_request(). Which incorrectly added elevator machinery into a call chain that isn't supposed to have any. To fix this introduce a blk-mq private blk_mq_request_bypass_insert() that blk_insert_cloned_request() calls to insert the request without involving any elevator that may be attached to the cloned request's request_queue. Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers") Cc: stable@vger.kernel.org Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com> Tested-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-11block: fix integer overflow in __blkdev_sectors_to_bio_pages()Mikulas Patocka1-2/+2
Fix possible integer overflow in __blkdev_sectors_to_bio_pages if sector_t is 32-bit. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: 615d22a51c04 ("block: Fix __blkdev_issue_zeroout loop") Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-11block: sed-opal: Set MBRDone on S3 resume path if TPER is MBREnabledScott Bauer2-0/+33
Users who are booting off their Opal enabled drives are having issues when they have a shadow MBR set up after s3/resume cycle. When the Drive has a shadow MBR setup the MBRDone flag is set to false upon power loss (S3/S4/S5). When the MBRDone flag is false I/O to LBA 0 -> LBA_END_MBR are remapped to the shadow mbr of the drive. If the drive contains useful data in the 0 -> end_mbr range upon s3 resume the user can never get to that data as the drive will keep remapping it to the MBR. To fix this when we unlock on S3 resume, we need to tell the drive that we're done with the shadow mbr (even though we didnt use it) by setting true to MBRDone. This way the drive will stop the remapping and the user can access their data. Acked-by Jon Derrick: <jonathan.derrick@intel.com> Signed-off-by: Scott Bauer <scott.bauer@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-09Merge branch 'for-4.14/block-postmerge' of git://git.kernel.dk/linux-blockLinus Torvalds4-72/+116
Pull followup block layer updates from Jens Axboe: "I ended up splitting the main pull request for this series into two, mainly because of clashes between NVMe fixes that went into 4.13 after the for-4.14 branches were split off. This pull request is mostly NVMe, but not exclusively. In detail, it contains: - Two pull request for NVMe changes from Christoph. Nothing new on the feature front, basically just fixes all over the map for the core bits, transport, rdma, etc. - Series from Bart, cleaning up various bits in the BFQ scheduler. - Series of bcache fixes, which has been lingering for a release or two. Coly sent this in, but patches from various people in this area. - Set of patches for BFQ from Paolo himself, updating both documentation and fixing some corner cases in performance. - Series from Omar, attempting to now get the 4k loop support correct. Our confidence level is higher this time. - Series from Shaohua for loop as well, improving O_DIRECT performance and fixing a use-after-free" * 'for-4.14/block-postmerge' of git://git.kernel.dk/linux-block: (74 commits) bcache: initialize dirty stripes in flash_dev_run() loop: set physical block size to logical block size bcache: fix bch_hprint crash and improve output bcache: Update continue_at() documentation bcache: silence static checker warning bcache: fix for gc and write-back race bcache: increase the number of open buckets bcache: Correct return value for sysfs attach errors bcache: correct cache_dirty_target in __update_writeback_rate() bcache: gc does not work when triggering by manual command bcache: Don't reinvent the wheel but use existing llist API bcache: do not subtract sectors_to_gc for bypassed IO bcache: fix sequential large write IO bypass bcache: Fix leak of bdev reference block/loop: remove unused field block/loop: fix use after free bfq: Use icq_to_bic() consistently bfq: Suppress compiler warnings about comparisons bfq: Check kstrtoul() return value bfq: Declare local functions static ...
2017-09-08block/cfq: cache rightmost rb_nodeDavidlohr Bueso1-5/+14
For the same reasons we already cache the leftmost pointer, apply the same optimization for rb_last() calls. Users must explicitly do this as rb_root_cached only deals with the smallest node. [dave@stgolabs.net: brain fart #1] Link: http://lkml.kernel.org/r/20170731155955.GD21328@linux-80c1.suse Link: http://lkml.kernel.org/r/20170719014603.19029-18-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08block/cfq: replace cfq_rb_root leftmost cachingDavidlohr Bueso1-50/+20
... with the generic rbtree flavor instead. No changes in semantics whatsoever. Link: http://lkml.kernel.org/r/20170719014603.19029-11-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-07Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds1-3/+4
Pull SCSI updates from James Bottomley: "This is mostly updates of the usual suspects: lpfc, qla2xxx, hisi_sas, megaraid_sas, zfcp and a host of minor updates. The major driver change here is the elimination of the block based cciss driver in favour of the SCSI based hpsa driver (which now drives all the legacy cases cciss used to be required for). Plus a reset handler clean up and the redo of the SAS SMP handler to use bsg lib" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (279 commits) scsi: scsi-mq: Always unprepare before requeuing a request scsi: Show .retries and .jiffies_at_alloc in debugfs scsi: Improve requeuing behavior scsi: Call scsi_initialize_rq() for filesystem requests scsi: qla2xxx: Reset the logo flag, after target re-login. scsi: qla2xxx: Fix slow mem alloc behind lock scsi: qla2xxx: Clear fc4f_nvme flag scsi: qla2xxx: add missing includes for qla_isr scsi: qla2xxx: Fix an integer overflow in sysfs code scsi: aacraid: report -ENOMEM to upper layer from aac_convert_sgraw2() scsi: aacraid: get rid of one level of indentation scsi: aacraid: fix indentation errors scsi: storvsc: fix memory leak on ring buffer busy scsi: scsi_transport_sas: switch to bsg-lib for SMP passthrough scsi: smartpqi: remove the smp_handler stub scsi: hpsa: remove the smp_handler stub scsi: bsg-lib: pass the release callback through bsg_setup_queue scsi: Rework handling of scsi_device.vpd_pg8[03] scsi: Rework the code for caching Vital Product Data (VPD) scsi: rcu: Introduce rcu_swap_protected() ...
2017-09-07Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds1-1/+1
Pull MD updates from Shaohua Li: "This update mainly fixes bugs: - Make raid5 ppl support several ppl from Pawel - Several raid5-cache bug fixes from Song - Bitmap fixes from Neil and Me - One raid1/10 regression fix since 4.12 from Me - Other small fixes and cleanup" * tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: md/bitmap: disable bitmap_resize for file-backed bitmaps. raid5-ppl: Recovery support for multiple partial parity logs md: Runtime support for multiple ppls md/raid0: attach correct cgroup info in bio lib/raid6: align AVX512 constants to 512 bits, not bytes raid5: remove raid5_build_block md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_show md: replace seq_release_private with seq_release md: notify about new spare disk in the container md/raid1/10: reset bio allocated from mempool md/raid5: release/flush io in raid5_do_work() md/bitmap: copy correct data for bitmap super
2017-09-07Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-blockLinus Torvalds26-303/+444
Pull block layer updates from Jens Axboe: "This is the first pull request for 4.14, containing most of the code changes. It's a quiet series this round, which I think we needed after the churn of the last few series. This contains: - Fix for a registration race in loop, from Anton Volkov. - Overflow complaint fix from Arnd for DAC960. - Series of drbd changes from the usual suspects. - Conversion of the stec/skd driver to blk-mq. From Bart. - A few BFQ improvements/fixes from Paolo. - CFQ improvement from Ritesh, allowing idling for group idle. - A few fixes found by Dan's smatch, courtesy of Dan. - A warning fixup for a race between changing the IO scheduler and device remova. From David Jeffery. - A few nbd fixes from Josef. - Support for cgroup info in blktrace, from Shaohua. - Also from Shaohua, new features in the null_blk driver to allow it to actually hold data, among other things. - Various corner cases and error handling fixes from Weiping Zhang. - Improvements to the IO stats tracking for blk-mq from me. Can drastically improve performance for fast devices and/or big machines. - Series from Christoph removing bi_bdev as being needed for IO submission, in preparation for nvme multipathing code. - Series from Bart, including various cleanups and fixes for switch fall through case complaints" * 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits) kernfs: checking for IS_ERR() instead of NULL drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set drbd: Fix allyesconfig build, fix recent commit drbd: switch from kmalloc() to kmalloc_array() drbd: abort drbd_start_resync if there is no connection drbd: move global variables to drbd namespace and make some static drbd: rename "usermode_helper" to "drbd_usermode_helper" drbd: fix race between handshake and admin disconnect/down drbd: fix potential deadlock when trying to detach during handshake drbd: A single dot should be put into a sequence. drbd: fix rmmod cleanup, remove _all_ debugfs entries drbd: Use setup_timer() instead of init_timer() to simplify the code. drbd: fix potential get_ldev/put_ldev refcount imbalance during attach drbd: new disk-option disable-write-same drbd: Fix resource role for newly created resources in events2 drbd: mark symbols static where possible drbd: Send P_NEG_ACK upon write error in protocol != C drbd: add explicit plugging when submitting batches drbd: change list_for_each_safe to while(list_first_entry_or_null) drbd: introduce drbd_recv_header_maybe_unplug ...
2017-09-05Merge tag 'char-misc-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-miscLinus Torvalds1-5/+13
Pull char/misc driver updates from Greg KH: "Here is the big char/misc driver update for 4.14-rc1. Lots of different stuff in here, it's been an active development cycle for some reason. Highlights are: - updated binder driver, this brings binder up to date with what shipped in the Android O release, plus some more changes that happened since then that are in the Android development trees. - coresight updates and fixes - mux driver file renames to be a bit "nicer" - intel_th driver updates - normal set of hyper-v updates and changes - small fpga subsystem and driver updates - lots of const code changes all over the driver trees - extcon driver updates - fmc driver subsystem upadates - w1 subsystem minor reworks and new features and drivers added - spmi driver updates Plus a smattering of other minor driver updates and fixes. All of these have been in linux-next with no reported issues for a while" * tag 'char-misc-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (244 commits) ANDROID: binder: don't queue async transactions to thread. ANDROID: binder: don't enqueue death notifications to thread todo. ANDROID: binder: Don't BUG_ON(!spin_is_locked()). ANDROID: binder: Add BINDER_GET_NODE_DEBUG_INFO ioctl ANDROID: binder: push new transactions to waiting threads. ANDROID: binder: remove proc waitqueue android: binder: Add page usage in binder stats android: binder: fixup crash introduced by moving buffer hdr drivers: w1: add hwmon temp support for w1_therm drivers: w1: refactor w1_slave_show to make the temp reading functionality separate drivers: w1: add hwmon support structures eeprom: idt_89hpesx: Support both ACPI and OF probing mcb: Fix an error handling path in 'chameleon_parse_cells()' MCB: add support for SC31 to mcb-lpc mux: make device_type const char: virtio: constify attribute_group structures. Documentation/ABI: document the nvmem sysfs files lkdtm: fix spelling mistake: "incremeted" -> "incremented" perf: cs-etm: Fix ETMv4 CONFIGR entry in perf.data file nvmem: include linux/err.h from header ...
2017-09-04Merge branch 'linus' into locking/core, to fix up conflictsIngo Molnar7-35/+120
Conflicts: mm/page_alloc.c Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-03Merge tag 'for-linus-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdmaLinus Torvalds3-0/+58
Pull rdma updates from Doug Ledford: "This is a big pull request. Of note is that I'm sending you the new ioctl API for the rdma subsystem. We put it up on linux-api@, but didn't get much response. The API is complex, but it solves two different problems in one go: 1) The bi-directional nature of the RDMA file write calls, which created the security hole we had to handle (and for which the fix is now causing problems for systems in production, we were a bit over zealous in the fix and the ability to open a device, then fork, then create new queue pairs on the device and use them is broken). 2) The bloat caused by different vendors implementing extensions to the base verbs API. Each vendor's hardware is slightly different, and the hardware might be suitable for one extension but not another. By the time we add generic extensions for all the different ways that the different hardware can offload things, the API becomes bloated. Things like our completion structs have started to exceed a cache line in size because of all the elements needed to support this. That in turn shows up heavily in the performance graphs with a noticable drop in performance on 100Gigabit links as our completion structs go from occupying one cache line to 1+. This API makes things like the completion structs modular in a very similar way to netlink so that your structs can only include the items needed for the offloads/features you are actually using on a given queue pair. In that way we support everything, but only use what we need, and our structs stay smaller. The ioctl API is better explained by the posting on linux-api@ than I can explain it here, so I'll just leave it at that. The rest of the pull request is typical stuff. Updates for 4.14 kernel merge window - Lots of hfi1 driver updates (mixed with a few qib and core updates as well) - rxe updates - various mlx updates - Set default roce type to RoCEv2 - Several larger fixes for bnxt_re that were too big for -rc - Several larger fixes for qedr that, likewise, were too big for -rc - Misc core changes - Make the hns_roce driver compilable on arches other than aarch64 so we can more easily debug build issues related to it - Add rdma-netlink infrastructure updates - Add automatic IRQ affinity infrastructure - Add 32bit lid support - Lots of misc fixes across the subsystem from random people - Autoloading of RDMA netlink modules - PCI pool cleanups from Romain Perier - mlx5 driver feature additions and fixes - Hardware tag matchine feature - Fix sleeping in atomic when resolving roce ah - Add experimental ioctl interface as posted to linux-api@" * tag 'for-linus-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (328 commits) IB/core: Expose ioctl interface through experimental Kconfig IB/core: Assign root to all drivers IB/core: Add completion queue (cq) object actions IB/core: Add legacy driver's user-data IB/core: Export ioctl enum types to user-space IB/core: Explicitly destroy an object while keeping uobject IB/core: Add macros for declaring methods and attributes IB/core: Add uverbs merge trees functionality IB/core: Add DEVICE object and root tree structure IB/core: Declare an object instead of declaring only type attributes IB/core: Add new ioctl interface RDMA/vmw_pvrdma: Fix a signedness RDMA/vmw_pvrdma: Report network header type in WC IB/core: Add might_sleep() annotation to ib_init_ah_from_wc() IB/cm: Fix sleeping in atomic when RoCE is used IB/core: Add support to finalize objects in one transaction IB/core: Add a generic way to execute an operation on a uobject Documentation: Hardware tag matching IB/mlx5: Support IB_SRQT_TM net/mlx5: Add XRQ support ...
2017-09-01bfq: Use icq_to_bic() consistentlyBart Van Assche1-1/+1
Some code uses icq_to_bic() to convert an io_cq pointer to a bfq_io_cq pointer while other code uses a direct cast. Convert the code that uses a direct cast such that it uses icq_to_bic(). Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-01bfq: Suppress compiler warnings about comparisonsBart Van Assche1-10/+10
This patch avoids that the following warnings are reported when building with W=1: block/bfq-iosched.c: In function 'bfq_back_seek_max_store': block/bfq-iosched.c:4860:13: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] if (__data < (MIN)) \ ^ block/bfq-iosched.c:4876:1: note: in expansion of macro 'STORE_FUNCTION' STORE_FUNCTION(bfq_back_seek_max_store, &bfqd->bfq_back_max, 0, INT_MAX, 0); ^~~~~~~~~~~~~~ block/bfq-iosched.c: In function 'bfq_slice_idle_store': block/bfq-iosched.c:4860:13: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] if (__data < (MIN)) \ ^ block/bfq-iosched.c:4879:1: note: in expansion of macro 'STORE_FUNCTION' STORE_FUNCTION(bfq_slice_idle_store, &bfqd->bfq_slice_idle, 0, INT_MAX, 2); ^~~~~~~~~~~~~~ block/bfq-iosched.c: In function 'bfq_slice_idle_us_store': block/bfq-iosched.c:4892:13: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] if (__data < (MIN)) \ ^ block/bfq-iosched.c:4899:1: note: in expansion of macro 'USEC_STORE_FUNCTION' USEC_STORE_FUNCTION(bfq_slice_idle_us_store, &bfqd->bfq_slice_idle, 0, ^~~~~~~~~~~~~~~~~~~ Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-01bfq: Check kstrtoul() return valueBart Van Assche1-15/+37
Make sysfs writes fail for invalid numbers instead of storing uninitialized data copied from the stack. This patch removes all uninitialized_var() occurrences from the BFQ source code. Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-01bfq: Declare local functions staticBart Van Assche1-9/+9
Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-01bfq: Annotate fall-through in a switch statementBart Van Assche1-0/+1
This patch avoids that gcc 7 issues a warning about fall-through when building with W=1. Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-31compat_hdio_ioctl: Fix a declarationBart Van Assche1-1/+1
This patch avoids that sparse reports the following warning messages: block/compat_ioctl.c:85:11: warning: incorrect type in assignment (different address spaces) block/compat_ioctl.c:85:11: expected unsigned long *[noderef] <asn:1>p block/compat_ioctl.c:85:11: got void [noderef] <asn:1>* block/compat_ioctl.c:91:21: warning: incorrect type in argument 1 (different address spaces) block/compat_ioctl.c:91:21: expected void const volatile [noderef] <asn:1>*<noident> block/compat_ioctl.c:91:21: got unsigned long *[noderef] <asn:1>p block/compat_ioctl.c:87:53: warning: dereference of noderef expression block/compat_ioctl.c:91:21: warning: dereference of noderef expression Fixes: commit d597580d3737 ("generic ...copy_..._user primitives") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-08-31block, bfq: guarantee update_next_in_service always returns an eligible entityPaolo Valente1-6/+8
If the function bfq_update_next_in_service is invoked as a consequence of the activation or requeueing of an entity, say E, then it doesn't invoke bfq_lookup_next_entity to get the next-in-service entity. In contrast, it follows a shorter path: if E happens to be eligible (see commit "bfq-sq-mq: make lookup_next_entity push up vtime on expirations" for details on eligibility) and to have a lower virtual finish time than the current candidate as next-in-service entity, then E directly becomes the next-in-service entity. Unfortunately, there is a corner case for which this shorter path makes bfq_update_next_in_service choose a non eligible entity: it occurs if both E and the current next-in-service entity happen to be non eligible when bfq_update_next_in_service is invoked. In this case, E is not set as next-in-service, and, since bfq_lookup_next_entity is not invoked, the state of the parent entity is not updated so as to end up with an eligible entity as the proper next-in-service entity. In this respect, next-in-service is actually allowed to be non eligible while some queue is in service: since no system-virtual-time push-up can be performed in that case (see again commit "bfq-sq-mq: make lookup_next_entity push up vtime on expirations" for details), next-in-service is chosen, speculatively, as a function of the possible value that the system virtual time may get after a push up. But the correctness of the schedule breaks if next-in-service is still a non eligible entity when it is time to set in service the next entity. Unfortunately, this may happen in the above corner case. This commit fixes this problem by making bfq_update_next_in_service invoke bfq_lookup_next_entity not only if the above shorter path cannot be taken, but also if the shorter path is taken but fails to yield an eligible next-in-service entity. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-31block, bfq: remove direct switch to an entity in higher classPaolo Valente1-14/+5
If the function bfq_update_next_in_service is invoked as a consequence of the activation or requeueing of an entity, say E, and finds out that E belongs to a higher-priority class than that of the current next-in-service entity, then it sets next_in_service directly to E. But this may lead to anomalous schedules, because E may happen not be eligible for service, because its virtual start time is higher than the system virtual time for its service tree. This commit addresses this issue by simply removing this direct switch. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-31block, bfq: make lookup_next_entity push up vtime on expirationsPaolo Valente3-19/+47
To provide a very smooth service, bfq starts to serve a bfq_queue only if the queue is 'eligible', i.e., if the same queue would have started to be served in the ideal, perfectly fair system that bfq simulates internally. This is obtained by associating each queue with a virtual start time, and by computing a special system virtual time quantity: a queue is eligible only if the system virtual time has reached the virtual start time of the queue. Finally, bfq guarantees that, when a new queue must be set in service, there is always at least one eligible entity for each active parent entity in the scheduler. To provide this guarantee, the function __bfq_lookup_next_entity pushes up, for each parent entity on which it is invoked, the system virtual time to the minimum among the virtual start times of the entities in the active tree for the parent entity (more precisely, the push up occurs if the system virtual time happens to be lower than all such virtual start times). There is however a circumstance in which __bfq_lookup_next_entity cannot push up the system virtual time for a parent entity, even if the system virtual time is lower than the virtual start times of all the child entities in the active tree. It happens if one of the child entities is in service. In fact, in such a case, there is already an eligible entity, the in-service one, even if it may not be not present in the active tree (because in-service entities may be removed from the active tree). Unfortunately, in the last re-design of the hierarchical-scheduling engine, the reset of the pointer to the in-service entity for a given parent entity--reset to be done as a consequence of the expiration of the in-service entity--always happens after the function __bfq_lookup_next_entity has been invoked. This causes the function to think that there is still an entity in service for the parent entity, and then that the system virtual time cannot be pushed up, even if actually such a no-more-in-service entity has already been properly reinserted into the active tree (or in some other tree if no more active). Yet, the system virtual time *had* to be pushed up, to be ready to correctly choose the next queue to serve. Because of the lack of this push up, bfq may wrongly set in service a queue that had been speculatively pre-computed as the possible next-in-service queue, but that would no more be the one to serve after the expiration and the reinsertion into the active trees of the previously in-service entities. This commit addresses this issue by making __bfq_lookup_next_entity properly push up the system virtual time if an expiration is occurring. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-29scsi: bsg-lib: pass the release callback through bsg_setup_queueChristoph Hellwig1-3/+4
The SAS code will need it. Also mark the name argument const to match bsg_register_queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-08-29bsg: remove #if 0'ed codeChristoph Hellwig1-7/+0
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-29mq-deadline: Enable auto-loading when built as moduleBen Hutchings1-0/+1
The block core requests modules with the "-iosched" name suffix, but mq-deadline does not have that suffix. Add an alias. Fixes: 945ffb60c11d ("mq-deadline: add blk-mq adaptation of the deadline ...") Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-29bfq: Re-enable auto-loading when built as a moduleBen Hutchings1-0/+1
The block core requests modules with the "-iosched" name suffix, but bfq no longer has that suffix. Add an alias. Fixes: ea25da48086d ("block, bfq: split bfq-iosched.c into multiple ...") Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-29block: Make blk_dequeue_request() staticDamien Le Moal2-5/+1
The only caller of this function is blk_start_request() in the same file. Fix blk_start_request() description accordingly. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-29smp: Avoid using two cache lines for struct call_single_dataYing Huang1-1/+1
struct call_single_data is used in IPIs to transfer information between CPUs. Its size is bigger than sizeof(unsigned long) and less than cache line size. Currently it is not allocated with any explicit alignment requirements. This makes it possible for allocated call_single_data to cross two cache lines, which results in double the number of the cache lines that need to be transferred among CPUs. This can be fixed by requiring call_single_data to be aligned with the size of call_single_data. Currently the size of call_single_data is the power of 2. If we add new fields to call_single_data, we may need to add padding to make sure the size of new definition is the power of 2 as well. Fortunately, this is enforced by GCC, which will report bad sizes. To set alignment requirements of call_single_data to the size of call_single_data, a struct definition and a typedef is used. To test the effect of the patch, I used the vm-scalability multiple thread swap test case (swap-w-seq-mt). The test will create multiple threads and each thread will eat memory until all RAM and part of swap is used, so that huge number of IPIs are triggered when unmapping memory. In the test, the throughput of memory writing improves ~5% compared with misaligned call_single_data, because of faster IPIs. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Huang, Ying <ying.huang@intel.com> [ Add call_single_data_t and align with size of call_single_data. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/87bmnqd6lz.fsf@yhuang-mobile.sh.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-28Merge tag 'v4.13-rc7' into for-4.14/block-postmergeJens Axboe8-114/+178
Linux 4.13-rc7 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-28block: fix warning when I/O elevator is changed as request_queue is being removedDavid Jeffery2-0/+6
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>
2017-08-28block, scheduler: convert xxx_var_store to voidweiping zhang4-33/+31
The last parameter "count" never be used in xxx_var_store, convert these functions to void. Signed-off-by: weiping zhang <zhangweiping@didichuxing.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-28Merge 4.13-rc7 into char-misc-nextGreg Kroah-Hartman5-38/+70
We want the binder fix in here as well for testing and merge issues. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-25blkcg: avoid free blkcg_root when failed to alloc blkcg policyweiping zhang1-3/+5
this patch fix two errors, firstly avoid kfree blk_root, secondly not free(blkcg) ,if blkcg alloc fail(blkcg == NULL), just unlock that mutex; Signed-off-by: weiping zhang <zhangweiping@didichuxing.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-25md/raid0: attach correct cgroup info in bioShaohua Li1-1/+1
The discard bio doesn't attach the original bio cgroup info. Normal bio is cloned, so is fine. Signed-off-by: Shaohua Li <shli@fb.com>
2017-08-25block: update comments to reflect REQ_FLUSH -> REQ_PREFLUSH renameOmar Sandoval1-12/+12
Normally I wouldn't bother with this, but in my opinion the comments are the most important part of this whole file since without them no one would have any clue how this insanity works. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-25blk-mq-debugfs: Add names for recently added flagsBart Van Assche1-0/+3
The symbolic constants QUEUE_FLAG_SCSI_PASSTHROUGH, QUEUE_FLAG_QUIESCED and REQ_NOWAIT are missing from blk-mq-debugfs.c. Add these to blk-mq-debugfs.c such that these appear as names in debugfs instead of as numbers. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-24compat_hdio_ioctl: Fix a declarationBart Van Assche1-1/+1
This patch avoids that sparse reports the following warning messages: block/compat_ioctl.c:85:11: warning: incorrect type in assignment (different address spaces) block/compat_ioctl.c:85:11: expected unsigned long *[noderef] <asn:1>p block/compat_ioctl.c:85:11: got void [noderef] <asn:1>* block/compat_ioctl.c:91:21: warning: incorrect type in argument 1 (different address spaces) block/compat_ioctl.c:91:21: expected void const volatile [noderef] <asn:1>*<noident> block/compat_ioctl.c:91:21: got unsigned long *[noderef] <asn:1>p block/compat_ioctl.c:87:53: warning: dereference of noderef expression block/compat_ioctl.c:91:21: warning: dereference of noderef expression Fixes: commit d597580d3737 ("generic ...copy_..._user primitives") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-24block: remove blk_free_devt in add_partitionweiping zhang1-1/+0
put_device(pdev) will call pdev->type->release finally, and blk_free_devt has been called in part_release(), so remove it. Signed-off-by: weiping zhang <zhangweiping@didichuxing.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-24bsg-lib: fix kernel panic resulting from missing allocation of reply-bufferBenjamin Block1-30/+44
Since we split the scsi_request out of struct request bsg fails to provide a reply-buffer for the drivers. This was done via the pointer for sense-data, that is not preallocated anymore. Failing to allocate/assign it results in illegal dereferences because LLDs use this pointer unquestioned. An example panic on s390x, using the zFCP driver, looks like this (I had debugging on, otherwise NULL-pointer dereferences wouldn't even panic on s390x): Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6403 Fault in home space mode while using kernel ASCE. AS:0000000001590007 R3:0000000000000024 Oops: 0038 ilc:2 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: <Long List> CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.12.0-bsg-regression+ #3 Hardware name: IBM 2964 N96 702 (z/VM 6.4.0) task: 0000000065cb0100 task.stack: 0000000065cb4000 Krnl PSW : 0704e00180000000 000003ff801e4156 (zfcp_fc_ct_els_job_handler+0x16/0x58 [zfcp]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000001 000000005fa9d0d0 000000005fa9d078 0000000000e16866 000003ff00000290 6b6b6b6b6b6b6b6b 0000000059f78f00 000000000000000f 00000000593a0958 00000000593a0958 0000000060d88800 000000005ddd4c38 0000000058b50100 07000000659cba08 000003ff801e8556 00000000659cb9a8 Krnl Code: 000003ff801e4146: e31020500004 lg %r1,80(%r2) 000003ff801e414c: 58402040 l %r4,64(%r2) #000003ff801e4150: e35020200004 lg %r5,32(%r2) >000003ff801e4156: 50405004 st %r4,4(%r5) 000003ff801e415a: e54c50080000 mvhi 8(%r5),0 000003ff801e4160: e33010280012 lt %r3,40(%r1) 000003ff801e4166: a718fffb lhi %r1,-5 000003ff801e416a: 1803 lr %r0,%r3 Call Trace: ([<000003ff801e8556>] zfcp_fsf_req_complete+0x726/0x768 [zfcp]) [<000003ff801ea82a>] zfcp_fsf_reqid_check+0x102/0x180 [zfcp] [<000003ff801eb980>] zfcp_qdio_int_resp+0x230/0x278 [zfcp] [<00000000009b91b6>] qdio_kick_handler+0x2ae/0x2c8 [<00000000009b9e3e>] __tiqdio_inbound_processing+0x406/0xc10 [<00000000001684c2>] tasklet_action+0x15a/0x1d8 [<0000000000bd28ec>] __do_softirq+0x3ec/0x848 [<00000000001675a4>] irq_exit+0x74/0xf8 [<000000000010dd6a>] do_IRQ+0xba/0xf0 [<0000000000bd19e8>] io_int_handler+0x104/0x2d4 [<00000000001033b6>] enabled_wait+0xb6/0x188 ([<000000000010339e>] enabled_wait+0x9e/0x188) [<000000000010396a>] arch_cpu_idle+0x32/0x50 [<0000000000bd0112>] default_idle_call+0x52/0x68 [<00000000001cd0fa>] do_idle+0x102/0x188 [<00000000001cd41e>] cpu_startup_entry+0x3e/0x48 [<0000000000118c64>] smp_start_secondary+0x11c/0x130 [<0000000000bd2016>] restart_int_handler+0x62/0x78 [<0000000000000000>] (null) INFO: lockdep is turned off. Last Breaking-Event-Address: [<000003ff801e41d6>] zfcp_fc_ct_job_handler+0x3e/0x48 [zfcp] Kernel panic - not syncing: Fatal exception in interrupt This patch moves bsg-lib to allocate and setup struct bsg_job ahead of time, including the allocation of a buffer for the reply-data. This means, struct bsg_job is not allocated separately anymore, but as part of struct request allocation - similar to struct scsi_cmd. Reflect this in the function names that used to handle creation/destruction of struct bsg_job. Reported-by: Steffen Maier <maier@linux.vnet.ibm.com> Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Benjamin Block <bblock@linux.vnet.ibm.com> Fixes: 82ed4db499b8 ("block: split scsi_request out of struct request") Cc: <stable@vger.kernel.org> #4.11+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-24bio-integrity: Fix regression if profile verify_fn is NULLMilan Broz1-1/+4
In dm-integrity target we register integrity profile that have both generate_fn and verify_fn callbacks set to NULL. This is used if dm-integrity is stacked under a dm-crypt device for authenticated encryption (integrity payload contains authentication tag and IV seed). In this case the verification is done through own crypto API processing inside dm-crypt; integrity profile is only holder of these data. (And memory is owned by dm-crypt as well.) After the commit (and previous changes) Commit 7c20f11680a441df09de7235206f70115fbf6290 Author: Christoph Hellwig <hch@lst.de> Date: Mon Jul 3 16:58:43 2017 -0600 bio-integrity: stop abusing bi_end_io we get this crash: : BUG: unable to handle kernel NULL pointer dereference at (null) : IP: (null) : *pde = 00000000 ... : : Workqueue: kintegrityd bio_integrity_verify_fn : task: f48ae180 task.stack: f4b5c000 : EIP: (null) : EFLAGS: 00210286 CPU: 0 : EAX: f4b5debc EBX: 00001000 ECX: 00000001 EDX: 00000000 : ESI: 00001000 EDI: ed25f000 EBP: f4b5dee8 ESP: f4b5dea4 : DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 : CR0: 80050033 CR2: 00000000 CR3: 32823000 CR4: 001406d0 : Call Trace: : ? bio_integrity_process+0xe3/0x1e0 : bio_integrity_verify_fn+0xea/0x150 : process_one_work+0x1c7/0x5c0 : worker_thread+0x39/0x380 : kthread+0xd6/0x110 : ? process_one_work+0x5c0/0x5c0 : ? kthread_worker_fn+0x100/0x100 : ? kthread_worker_fn+0x100/0x100 : ret_from_fork+0x19/0x24 : Code: Bad EIP value. : EIP: (null) SS:ESP: 0068:f4b5dea4 : CR2: 0000000000000000 Patch just skip the whole verify workqueue if verify_fn is set to NULL. Fixes: 7c20f116 ("bio-integrity: stop abusing bi_end_io") Signed-off-by: Milan Broz <gmazyland@gmail.com> [hch: trivial whitespace fix] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23blk-throttle: cap discard request sizeShaohua Li1-4/+14
discard request usually is very big and easily use all bandwidth budget of a cgroup. discard request size doesn't really mean the size of data written, so it doesn't make sense to account it into bandwidth budget. Jens pointed out treating the size 0 doesn't make sense too, because discard request does have cost. But it's not easy to find the actual cost. This patch simply makes the size one sector. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23block, bfq: fix error handle in bfq_initweiping zhang1-1/+3
if elv_register fail, bfq_pool should be free. Signed-off-by: weiping zhang <zhangweiping@didichuxing.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23block: replace bi_bdev with a gendisk pointer and partitions indexChristoph Hellwig7-74/+70
This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23block: add a __disk_get_part helperChristoph Hellwig2-13/+15
This helper allows looking up a partion under RCU protection without grabbing a reference to it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23block: reject attempts to allocate more than DISK_MAX_PARTS partitionsChristoph Hellwig1-0/+7
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23block: Warn if blk_queue_rq_timed_out() is called for a blk-mq queueBart Van Assche1-0/+1
The timeout handler set by blk_queue_rq_timed_out() is only used in single queue mode. Calling this function for blk-mq drivers is wrong. Hence issue a warning if this function is called by a blk-mq driver. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-18block: Relax a check in blk_start_queue()Bart Van Assche1-1/+1
Calling blk_start_queue() from interrupt context with the queue lock held and without disabling IRQs, as the skd driver does, is safe. This patch avoids that loading the skd driver triggers the following warning: WARNING: CPU: 11 PID: 1348 at block/blk-core.c:283 blk_start_queue+0x84/0xa0 RIP: 0010:blk_start_queue+0x84/0xa0 Call Trace: skd_unquiesce_dev+0x12a/0x1d0 [skd] skd_complete_internal+0x1e7/0x5a0 [skd] skd_complete_other+0xc2/0xd0 [skd] skd_isr_completion_posted.isra.30+0x2a5/0x470 [skd] skd_isr+0x14f/0x180 [skd] irq_forced_thread_fn+0x2a/0x70 irq_thread+0x144/0x1a0 kthread+0x125/0x140 ret_from_fork+0x2a/0x40 Fixes: commit a038e2536472 ("[PATCH] blk_start_queue() must be called with irq disabled - add warning") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Andrew Morton <akpm@osdl.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-18genhd: Annotate all part and part_tbl pointer dereferencesBart Van Assche2-8/+22
Annotate gendisk.part_tbl and disk_part_tbl.part dereferences with rcu_dereference_protected(). This patch does not change the behavior of the modified code but ensures that sparse does not complain about disk->part_tbl manipulations nor about part_tbl->part accesses. Additionally, improve documentation of the locking requirements of the modified functions. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>