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* blk-mq: document the need to have STARTED and COMPLETED share a byteJens Axboe2017-10-042-0/+13
| | | | | | | | | | For memory ordering guarantees on stores, we need to ensure that these two bits share the same byte of storage in the unsigned long. Add a comment as to why, and a BUILD_BUG_ON() to ensure that we don't violate this requirement. Suggested-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: attempt to fix atomic flag memory orderingPeter Zijlstra2017-10-042-13/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Attempt to untangle the ordering in blk-mq. The patch introducing the single smp_mb__before_atomic() is obviously broken in that it doesn't clearly specify a pairing barrier and an obtained guarantee. The comment is further misleading in that it hints that the deadline store and the COMPLETE store also need to be ordered, but AFAICT there is no such dependency. However what does appear to be important is the clear happening _after_ the store, and that worked by pure accident. This clarifies blk_mq_start_request() -- we should not get there with STARTING set -- this simplifies the code and makes the barrier usage sane (the old code could be read to allow not having _any_ atomic after the barrier, in which case the barrier hasn't got anything to order). We then also introduce the missing pairing barrier for it. Also down-grade the barrier to smp_wmb(), this is cheaper for PowerPC/ARM and doesn't cost anything extra on x86. And it documents the STARTING vs COMPLETE ordering. Although I've not been entirely successful in reverse engineering the blk-mq state machine so there might still be more funnies around timeout vs requeue. If I got anything wrong, feel free to educate me by adding comments to clarify things ;-) Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Will Deacon <will.deacon@arm.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Fixes: 538b75341835 ("blk-mq: request deadline must be visible before marking rq as started") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move __elv_next_request to blk-core.cChristoph Hellwig2017-10-032-41/+40
| | | | | | | No need to have this helper inline in a header. Also drop the __ prefix. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block, bfq: decrease burst size when queues in burst exitPaolo Valente2017-10-031-9/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If many queues belonging to the same group happen to be created shortly after each other, then the concurrent processes associated with these queues have typically a common goal, and they get it done as soon as possible if not hampered by device idling. Examples are processes spawned by git grep, or by systemd during boot. As for device idling, this mechanism is currently necessary for weight raising to succeed in its goal: privileging I/O. In view of these facts, BFQ does not provide the above queues with either weight raising or device idling. On the other hand, a burst of queue creations may be caused also by the start-up of a complex application. In this case, these queues need usually to be served one after the other, and as quickly as possible, to maximise responsiveness. Therefore, in this case the best strategy is to weight-raise all the queues created during the burst, i.e., the exact opposite of the strategy for the above case. To distinguish between the two cases, BFQ uses an empirical burst-size threshold, found through extensive tests and monitoring of daily usage. Only large bursts, i.e., burst with a size above this threshold, are considered as generated by a high number of parallel processes. In this respect, upstart-based boot proved to be rather hard to detect as generating a large burst of queue creations, because with upstart most of the queues created in a burst exit *before* the next queues in the same burst are created. To address this issue, I changed the burst-detection mechanism so as to not decrease the size of the current burst even if one of the queues in the burst is eliminated. Unfortunately, this missing decrease causes false positives on very fast systems: on the start-up of a complex application, such as libreoffice writer, so many queues are created, served and exited shortly after each other, that a large burst of queue creations is wrongly detected as occurring. These false positives just disappear if the size of a burst is decreased when one of the queues in the burst exits. This commit restores the missing burst-size decrease, relying of the fact that upstart is apparently unlikely to be used on systems running this and future versions of the kernel. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Mauro Andreolini <mauro.andreolini@unimore.it> Signed-off-by: Angelo Ruocco <angeloruocco90@gmail.com> Tested-by: Mirko Montanari <mirkomontanari91@gmail.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block, bfq: let early-merged queues be weight-raised on split tooPaolo Valente2017-10-031-5/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | A just-created bfq_queue, say Q, may happen to be merged with another bfq_queue on the very first invocation of the function __bfq_insert_request. In such a case, even if Q would clearly deserve interactive weight raising (as it has just been created), the function bfq_add_request does not make it to be invoked for Q, and thus to activate weight raising for Q. As a consequence, when the state of Q is saved for a possible future restore, after a split of Q from the other bfq_queue(s), such a state happens to be (unjustly) non-weight-raised. Then the bfq_queue will not enjoy any weight raising on the split, even if should still be in an interactive weight-raising period when the split occurs. This commit solves this problem as follows, for a just-created bfq_queue that is being early-merged: it stores directly, in the saved state of the bfq_queue, the weight-raising state that would have been assigned to the bfq_queue if not early-merged. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Tested-by: Angelo Ruocco <angeloruocco90@gmail.com> Tested-by: Mirko Montanari <mirkomontanari91@gmail.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block, bfq: check and switch back to interactive wr also on queue splitPaolo Valente2017-10-031-38/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As already explained in the message of commit "block, bfq: fix wrong init of saved start time for weight raising", if a soft real-time weight-raising period happens to be nested in a larger interactive weight-raising period, then BFQ restores the interactive weight raising at the end of the soft real-time weight raising. In particular, BFQ checks whether the latter has ended only on request dispatches. Unfortunately, the above scheme fails to restore interactive weight raising in the following corner case: if a bfq_queue, say Q, 1) Is merged with another bfq_queue while it is in a nested soft real-time weight-raising period. The weight-raising state of Q is then saved, and not considered any longer until a split occurs. 2) Is split from the other bfq_queue(s) at a time instant when its soft real-time weight raising is already finished. On the split, while resuming the previous, soft real-time weight-raised state of the bfq_queue Q, BFQ checks whether the current soft real-time weight-raising period is actually over. If so, BFQ switches weight raising off for Q, *without* checking whether the soft real-time period was actually nested in a non-yet-finished interactive weight-raising period. This commit addresses this issue by adding the above missing check in bfq_queue splits, and restoring interactive weight raising if needed. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Tested-by: Angelo Ruocco <angeloruocco90@gmail.com> Tested-by: Mirko Montanari <mirkomontanari91@gmail.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block, bfq: fix wrong init of saved start time for weight raisingPaolo Valente2017-10-031-19/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit fixes a bug that causes bfq to fail to guarantee a high responsiveness on some drives, if there is heavy random read+write I/O in the background. More precisely, such a failure allowed this bug to be found [1], but the bug may well cause other yet unreported anomalies. BFQ raises the weight of the bfq_queues associated with soft real-time applications, to privilege the I/O, and thus reduce latency, for these applications. This mechanism is named soft-real-time weight raising in BFQ. A soft real-time period may happen to be nested into an interactive weight raising period, i.e., it may happen that, when a bfq_queue switches to a soft real-time weight-raised state, the bfq_queue is already being weight-raised because deemed interactive too. In this case, BFQ saves in a special variable wr_start_at_switch_to_srt, the time instant when the interactive weight-raising period started for the bfq_queue, i.e., the time instant when BFQ started to deem the bfq_queue interactive. This value is then used to check whether the interactive weight-raising period would still be in progress when the soft real-time weight-raising period ends. If so, interactive weight raising is restored for the bfq_queue. This restore is useful, in particular, because it prevents bfq_queues from losing their interactive weight raising prematurely, as a consequence of spurious, short-lived soft real-time weight-raising periods caused by wrong detections as soft real-time. If, instead, a bfq_queue switches to soft-real-time weight raising while it *is not* already in an interactive weight-raising period, then the variable wr_start_at_switch_to_srt has no meaning during the following soft real-time weight-raising period. Unfortunately the handling of this case is wrong in BFQ: not only the variable is not flagged somehow as meaningless, but it is also set to the time when the switch to soft real-time weight-raising occurs. This may cause an interactive weight-raising period to be considered mistakenly as still in progress, and thus a spurious interactive weight-raising period to start for the bfq_queue, at the end of the soft-real-time weight-raising period. In particular the spurious interactive weight-raising period will be considered as still in progress, if the soft-real-time weight-raising period does not last very long. The bfq_queue will then be wrongly privileged and, if I/O bound, will unjustly steal bandwidth to truly interactive or soft real-time bfq_queues, harming responsiveness and low latency. This commit fixes this issue by just setting wr_start_at_switch_to_srt to minus infinity (farthest past time instant according to jiffies macros): when the soft-real-time weight-raising period ends, certainly no interactive weight-raising period will be considered as still in progress. [1] Background I/O Type: Random - Background I/O mix: Reads and writes - Application to start: LibreOffice Writer in http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.13-IO-Laptop Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Angelo Ruocco <angeloruocco90@gmail.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Lee Tibbert <lee.tibbert@gmail.com> Tested-by: Mirko Montanari <mirkomontanari91@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: wire up completion notifier for laptop modeJens Axboe2017-10-031-0/+3
| | | | | | | | | | For some reason, the laptop mode IO completion notified was never wired up for blk-mq. Ensure that we trigger the callback appropriately, to arm the laptop mode flush timer. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <Bart.VanAssche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq-tag: kill unused tag enumsJens Axboe2017-10-011-6/+1
| | | | | | | We don't have any notion of a tagging cache anymore, and haven't for a long time. Kill off the unused enums. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: remove unused function hctx_allow_mergesweiping zhang2017-09-301-6/+0
| | | | | | | | | since 9bddeb2a5b981 "blk-mq: make per-sw-queue bio merge as default .bio_merge" there is no caller for this function. Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: weiping zhang <zhangweiping@didichuxing.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blkcg: delete unused APIsShaohua Li2017-09-261-31/+0
| | | | | | | | Nobody uses the APIs right now. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix a crash caused by wrong APIShaohua Li2017-09-251-1/+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>
* blktrace: Fix potential deadlock between delete & sysfs opsWaiman Long2017-09-251-0/+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>
* bsg-lib: don't free job in bsg_prepare_jobChristoph Hellwig2017-09-251-1/+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>
* block: directly insert blk-mq request from blk_insert_cloned_request()Jens Axboe2017-09-113-1/+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>
* block: fix integer overflow in __blkdev_sectors_to_bio_pages()Mikulas Patocka2017-09-111-2/+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>
* block: sed-opal: Set MBRDone on S3 resume path if TPER is MBREnabledScott Bauer2017-09-112-0/+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>
* Merge branch 'for-4.14/block-postmerge' of git://git.kernel.dk/linux-blockLinus Torvalds2017-09-094-72/+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 ...
| * bfq: Use icq_to_bic() consistentlyBart Van Assche2017-09-011-1/+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>
| * bfq: Suppress compiler warnings about comparisonsBart Van Assche2017-09-011-10/+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>
| * bfq: Check kstrtoul() return valueBart Van Assche2017-09-011-15/+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>
| * bfq: Declare local functions staticBart Van Assche2017-09-011-9/+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>
| * bfq: Annotate fall-through in a switch statementBart Van Assche2017-09-011-0/+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>
| * block, bfq: guarantee update_next_in_service always returns an eligible entityPaolo Valente2017-08-311-6/+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>
| * block, bfq: remove direct switch to an entity in higher classPaolo Valente2017-08-311-14/+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>
| * block, bfq: make lookup_next_entity push up vtime on expirationsPaolo Valente2017-08-313-19/+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>
| * Merge tag 'v4.13-rc7' into for-4.14/block-postmergeJens Axboe2017-08-288-114/+178
| |\ | | | | | | | | | | | | | | | Linux 4.13-rc7 Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | block/cfq: cache rightmost rb_nodeDavidlohr Bueso2017-09-081-5/+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>
* | | block/cfq: replace cfq_rb_root leftmost cachingDavidlohr Bueso2017-09-081-50/+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>
* | | Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds2017-09-071-3/+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() ...
| * | | scsi: bsg-lib: pass the release callback through bsg_setup_queueChristoph Hellwig2017-08-291-3/+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>
* | | | Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds2017-09-071-1/+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
| * | | | md/raid0: attach correct cgroup info in bioShaohua Li2017-08-251-1/+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>
* | | | | Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-blockLinus Torvalds2017-09-0726-303/+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 ...
| * | | | | bsg: remove #if 0'ed codeChristoph Hellwig2017-08-291-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | | | mq-deadline: Enable auto-loading when built as moduleBen Hutchings2017-08-291-0/+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>
| * | | | | bfq: Re-enable auto-loading when built as a moduleBen Hutchings2017-08-291-0/+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>
| * | | | | block: Make blk_dequeue_request() staticDamien Le Moal2017-08-292-5/+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>
| * | | | block: fix warning when I/O elevator is changed as request_queue is being ↵David Jeffery2017-08-282-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | removed 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>
| * | | | block, scheduler: convert xxx_var_store to voidweiping zhang2017-08-284-33/+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>
| * | | | blkcg: avoid free blkcg_root when failed to alloc blkcg policyweiping zhang2017-08-251-3/+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>
| * | | | block: update comments to reflect REQ_FLUSH -> REQ_PREFLUSH renameOmar Sandoval2017-08-251-12/+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>
| * | | | compat_hdio_ioctl: Fix a declarationBart Van Assche2017-08-241-1/+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>
| * | | | block: remove blk_free_devt in add_partitionweiping zhang2017-08-241-1/+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>
| * | | | bio-integrity: Fix regression if profile verify_fn is NULLMilan Broz2017-08-241-1/+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>
| * | | | block, bfq: fix error handle in bfq_initweiping zhang2017-08-231-1/+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>
| * | | | block: replace bi_bdev with a gendisk pointer and partitions indexChristoph Hellwig2017-08-237-74/+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>
| * | | | block: add a __disk_get_part helperChristoph Hellwig2017-08-232-13/+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>
| * | | | block: reject attempts to allocate more than DISK_MAX_PARTS partitionsChristoph Hellwig2017-08-231-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | | block: Warn if blk_queue_rq_timed_out() is called for a blk-mq queueBart Van Assche2017-08-231-0/+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>
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