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* blk-mq: make the polling code adaptiveJens Axboe2016-11-172-11/+82
| | | | | | | | | | | | | | | | | | | The previous commit introduced the hybrid sleep/poll mode. Take that one step further, and use the completion latencies to automatically sleep for half the mean completion time. This is a good approximation. This changes the 'io_poll_delay' sysfs file a bit to expose the various options. Depending on the value, the polling code will behave differently: -1 Never enter hybrid sleep mode 0 Use half of the completion mean for the sleep delay >0 Use this specific value as the sleep delay Signed-off-by: Jens Axboe <axboe@fb.com> Tested-By: Stephen Bates <sbates@raithlin.com> Reviewed-By: Stephen Bates <sbates@raithlin.com>
* blk-mq: implement hybrid poll mode for sync O_DIRECTJens Axboe2016-11-173-0/+80
| | | | | | | | | | | | | | | This patch enables a hybrid polling mode. Instead of polling after IO submission, we can induce an artificial delay, and then poll after that. For example, if the IO is presumed to complete in 8 usecs from now, we can sleep for 4 usecs, wake up, and then do our polling. This still puts a sleep/wakeup cycle in the IO path, but instead of the wakeup happening after the IO has completed, it'll happen before. With this hybrid scheme, we can achieve big latency reductions while still using the same (or less) amount of CPU. Signed-off-by: Jens Axboe <axboe@fb.com> Tested-By: Stephen Bates <sbates@raithlin.com> Reviewed-By: Stephen Bates <sbates@raithlin.com>
* blk-wbt: fix old-style function declarationArnd Bergmann2016-11-161-1/+1
| | | | | | | | | | | | The newly added driver causes a harmless warning in some configurations: block/blk-wbt.c:250:1: error: ‘inline’ is not at beginning of declaration [-Werror=old-style-declaration] static bool inline stat_sample_valid(struct blk_rq_stat *stat) This makes it use the expected format for the declaration. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: deal with stale req count of plug listMing Lei2016-11-162-1/+11
| | | | | | | | | | | | | | | | | In both legacy and mq path, req count of plug list is computed before allocating request, so the number can be stale when falling back to slept allocation, also the new introduced wbt can sleep too. This patch deals with the case by checking if plug list becomes empty, and fixes the KASAN report of 'BUG: KASAN: stack-out-of-bounds' which is introduced by Shaohua's patches of dispatching big request. Fixes: 600271d900002(blk-mq: immediately dispatch big size request) Fixes: 50d24c34403c6(block: immediately dispatch big size request) Cc: Shaohua Li <shli@fb.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* bsg: Add sparse annotations to bsg_request_fn()Bart Van Assche2016-11-141-0/+2
| | | | | | | Avoid that sparse complains about unbalanced lock actions. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-wbt: use BLK_STAT_{READ,WRITE} instead of 0/1Jens Axboe2016-11-111-6/+6
| | | | | | Since we have proper enums for the stats directions, use them. Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-wbt: remove stat opsJens Axboe2016-11-113-43/+8
| | | | | | | Again a leftover from when the throttling code was generic. Now that we just have the block user, get rid of the stat ops and indirections. Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-wbt: store queue instead of bdiJens Axboe2016-11-112-11/+13
| | | | | | | The bdi was a leftover from when the code was block layer agnostic. Now that we just support a block layer user, store the queue directly. Signed-off-by: Jens Axboe <axboe@fb.com>
* block: move poll code to blk-mqJens Axboe2016-11-112-46/+54
| | | | | | | | The poll code is blk-mq specific, let's move it to blk-mq.c. This is a prep patch for improving the polling code. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
* blk-mq: blk_mq_try_issue_directly() should lookup hardware queueJens Axboe2016-11-111-4/+4
| | | | | | | | | | | | A previous commit changed this to pass in the hardware queue, but it was using the wrong hardware queue. Hence a request that was allocated on one hardware queue ended up being issued on another one, and that caused IO timeouts and oopses on some drivers. Since the request holds hardware queue private resources, like a tag, we can't just issue it on a different hardware queue. Fixes: 2253efc850c4 ("blk-mq: Move more code into blk_mq_direct_issue_request()") Signed-off-by: Jens Axboe <axboe@fb.com>
* block: hook up writeback throttlingJens Axboe2016-11-106-4/+171
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enable throttling of buffered writeback to make it a lot more smooth, and has way less impact on other system activity. Background writeback should be, by definition, background activity. The fact that we flush huge bundles of it at the time means that it potentially has heavy impacts on foreground workloads, which isn't ideal. We can't easily limit the sizes of writes that we do, since that would impact file system layout in the presence of delayed allocation. So just throttle back buffered writeback, unless someone is waiting for it. The algorithm for when to throttle takes its inspiration in the CoDel networking scheduling algorithm. Like CoDel, blk-wb monitors the minimum latencies of requests over a window of time. In that window of time, if the minimum latency of any request exceeds a given target, then a scale count is incremented and the queue depth is shrunk. The next monitoring window is shrunk accordingly. Unlike CoDel, if we hit a window that exhibits good behavior, then we simply increment the scale count and re-calculate the limits for that scale value. This prevents us from oscillating between a close-to-ideal value and max all the time, instead remaining in the windows where we get good behavior. Unlike CoDel, blk-wb allows the scale count to to negative. This happens if we primarily have writes going on. Unlike positive scale counts, this doesn't change the size of the monitoring window. When the heavy writers finish, blk-bw quickly snaps back to it's stable state of a zero scale count. The patch registers a sysfs entry, 'wb_lat_usec'. This sets the latency target to me met. It defaults to 2 msec for non-rotational storage, and 75 msec for rotational storage. Setting this value to '0' disables blk-wb. Generally, a user would not have to touch this setting. We don't enable WBT on devices that are managed with CFQ, and have a non-root block cgroup attached. If we have a proportional share setup on this particular disk, then the wbt throttling will interfere with that. We don't have a strong need for wbt for that case, since we will rely on CFQ doing that for us. Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-wbt: add general throttling mechanismJens Axboe2016-11-103-0/+901
| | | | | | | | | | | | | | | | | | | | We can hook this up to the block layer, to help throttle buffered writes. wbt registers a few trace points that can be used to track what is happening in the system: wbt_lat: 259:0: latency 2446318 wbt_stat: 259:0: rmean=2446318, rmin=2446318, rmax=2446318, rsamples=1, wmean=518866, wmin=15522, wmax=5330353, wsamples=57 wbt_step: 259:0: step down: step=1, window=72727272, background=8, normal=16, max=32 This shows a sync issue event (wbt_lat) that exceeded it's time. wbt_stat dumps the current read/write stats for that window, and wbt_step shows a step down event where we now scale back writes. Each trace includes the device, 259:0 in this case. Signed-off-by: Jens Axboe <axboe@fb.com>
* block: add scalable completion tracking of requestsJens Axboe2016-11-108-3/+404
| | | | | | | | | | | | | | | | | | For legacy block, we simply track them in the request queue. For blk-mq, we track them on a per-sw queue basis, which we can then sum up through the hardware queues and finally to a per device state. The stats are tracked in, roughly, 0.1s interval windows. Add sysfs files to display the stats. The feature is off by default, to avoid any extra overhead. In-kernel users of it can turn it on by setting QUEUE_FLAG_STATS in the queue flags. We currently don't turn it on if someone just reads any of the stats files, that is something we could add as well. Signed-off-by: Jens Axboe <axboe@fb.com>
* block: cfq_cpd_alloc() should use @gfpTejun Heo2016-11-101-1/+1
| | | | | | | | | | | | cfq_cpd_alloc() which is the cpd_alloc_fn implementation for cfq was incorrectly hard coding GFP_KERNEL instead of using the mask specified through the @gfp parameter. This currently doesn't cause any actual issues because all current callers specify GFP_KERNEL. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: e4a9bde9589f ("blkcg: replace blkcg_policy->cpd_size with ->cpd_alloc/free_fn() methods") Signed-off-by: Jens Axboe <axboe@fb.com>
* block: set REQ_SYNC if we clear REQ_FUA|REQ_PREFLUSHJens Axboe2016-11-081-0/+7
| | | | | | | | | | | | | If we insert a flush request, we clear REQ_PREFLUSH and/or REQ_FUA, depending on flush settings. Since op_is_sync() factors those flags in for deciding whether this request is sync or not, we should set REQ_SYNC to avoid screwing up this accounting. This should be less fragile. Reported-by: Logan Gunthorpe <logang@deltatee.com> Fixes: b685d3d65ac ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous") Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Always schedule hctx->next_cpuGabriel Krisman Bertazi2016-11-061-3/+1
| | | | | | | | | | | | | | | | | | | Commit 0e87e58bf60e ("blk-mq: improve warning for running a queue on the wrong CPU") attempts to avoid triggering the WARN_ON in __blk_mq_run_hw_queue when the expected CPU is dead. Problem is, in the last batch execution before round robin, blk_mq_hctx_next_cpu can schedule a dead CPU and also update next_cpu to the next alive CPU in the mask, which will trigger the WARN_ON despite the previous workaround. The following patch fixes this scenario by always scheduling the value in hctx->next_cpu. This changes the moment when we round-robin the CPU running the hctx, but it really doesn't matter, since it still executes BLK_MQ_CPU_WORK_BATCH times in a row before switching to another CPU. Fixes: 0e87e58bf60e ("blk-mq: improve warning for running a queue on the wrong CPU") Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: add code to track actual device queue depthJens Axboe2016-11-051-0/+12
| | | | | | | | | | | | | | For blk-mq, ->nr_requests does track queue depth, at least at init time. But for the older queue paths, it's simply a soft setting. On top of that, it's generally larger than the hardware setting on purpose, to allow backup of requests for merging. Fill a hole in struct request with a 'queue_depth' member, that drivers can call to more closely inform the block layer of the real queue depth. Signed-off-by: Jens Axboe <axboe@fb.com> Reviewed-by: Jan Kara <jack@suse.cz>
* blk-mq: immediately dispatch big size requestShaohua Li2016-11-031-1/+6
| | | | | | | | This is corresponding part for blk-mq. Disk with multiple hardware queues doesn't need this as we only hold 1 request at most. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: immediately dispatch big size requestShaohua Li2016-11-031-1/+3
| | | | | | | | | | | | | | | | | | | | | | Currently block plug holds up to 16 non-mergeable requests. This makes sense if the request size is small, eg, reduce lock contention. But if request size is big enough, we don't need to worry about lock contention. Holding such request makes no sense and it lows the disk utilization. In practice, this improves 10% throughput for my raid5 sequential write workload. The size (128k) is arbitrary right now, but it makes sure lock contention is small. This probably could be more intelligent, eg, check average request size holded. Since this is mainly for sequential IO, probably not worthy. V2: check the last request instead of the first request, so as long as there is one big size request we flush the plug. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: drop q argument from bsg_validate_sgv4_hdrJohannes Thumshirn2016-11-031-2/+2
| | | | | | | | bsg_validate_sgv4_hdr() doesn't care about the request_queue, so drop it from it's arguments. Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Add a kick_requeue_list argument to blk_mq_requeue_request()Bart Van Assche2016-11-022-7/+8
| | | | | | | | | | | | | | Most blk_mq_requeue_request() and blk_mq_add_to_requeue_list() calls are followed by kicking the requeue list. Hence add an argument to these two functions that allows to kick the requeue list. This was proposed by Christoph Hellwig. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Introduce blk_mq_quiesce_queue()Bart Van Assche2016-11-022-7/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | blk_mq_quiesce_queue() waits until ongoing .queue_rq() invocations have finished. This function does *not* wait until all outstanding requests have finished (this means invocation of request.end_io()). The algorithm used by blk_mq_quiesce_queue() is as follows: * Hold either an RCU read lock or an SRCU read lock around .queue_rq() calls. The former is used if .queue_rq() does not block and the latter if .queue_rq() may block. * blk_mq_quiesce_queue() first calls blk_mq_stop_hw_queues() followed by synchronize_srcu() or synchronize_rcu(). The latter call waits for .queue_rq() invocations that started before blk_mq_quiesce_queue() was called. * The blk_mq_hctx_stopped() calls that control whether or not .queue_rq() will be called are called with the (S)RCU read lock held. This is necessary to avoid race conditions against blk_mq_quiesce_queue(). Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Remove blk_mq_cancel_requeue_work()Bart Van Assche2016-11-021-6/+0
| | | | | | | | | | | | | | | Since blk_mq_requeue_work() no longer restarts stopped queues canceling requeue work is no longer needed to prevent that a stopped queue would be restarted. Hence remove this function. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Keith Busch <keith.busch@intel.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Avoid that requeueing starts stopped queuesBart Van Assche2016-11-021-5/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since blk_mq_requeue_work() starts stopped queues and since execution of this function can be scheduled after a queue has been stopped it is not possible to stop queues without using an additional state variable to track whether or not the queue has been stopped. Hence modify blk_mq_requeue_work() such that it does not start stopped queues. My conclusion after a review of the blk_mq_stop_hw_queues() and blk_mq_{delay_,}kick_requeue_list() callers is as follows: * In the dm driver starting and stopping queues should only happen if __dm_suspend() or __dm_resume() is called and not if the requeue list is processed. * In the SCSI core queue stopping and starting should only be performed by the scsi_internal_device_block() and scsi_internal_device_unblock() functions but not by any other function. Although the blk_mq_stop_hw_queue() call in scsi_queue_rq() may help to reduce CPU load if a LLD queue is full, figuring out whether or not a queue should be restarted when requeueing a command would require to introduce additional locking in scsi_mq_requeue_cmd() to avoid a race with scsi_internal_device_block(). Avoid this complexity by removing the blk_mq_stop_hw_queue() call from scsi_queue_rq(). * In the NVMe core only the functions that call blk_mq_start_stopped_hw_queues() explicitly should start stopped queues. * A blk_mq_start_stopped_hwqueues() call must be added in the xen-blkfront driver in its blkif_recover() function. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Roger Pau Monné <roger.pau@citrix.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: James Bottomley <jejb@linux.vnet.ibm.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Move more code into blk_mq_direct_issue_request()Bart Van Assche2016-11-021-8/+10
| | | | | | | | | | | | | | | | Move the "hctx stopped" test and the insert request calls into blk_mq_direct_issue_request(). Rename that function into blk_mq_try_issue_directly() to reflect its new semantics. Pass the hctx pointer to that function instead of looking it up a second time. These changes avoid that code has to be duplicated in the next patch. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Introduce blk_mq_queue_stopped()Bart Van Assche2016-11-021-0/+20
| | | | | | | | | | | | | | The function blk_queue_stopped() allows to test whether or not a traditional request queue has been stopped. Introduce a helper function that allows block drivers to query easily whether or not one or more hardware contexts of a blk-mq queue have been stopped. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Introduce blk_mq_hctx_stopped()Bart Van Assche2016-11-022-6/+11
| | | | | | | | | | | | | Multiple functions test the BLK_MQ_S_STOPPED bit so introduce a helper function that performs this test. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: Do not invoke .queue_rq() for a stopped queueBart Van Assche2016-11-021-3/+3
| | | | | | | | | | | | | | | | The meaning of the BLK_MQ_S_STOPPED flag is "do not call .queue_rq()". Hence modify blk_mq_make_request() such that requests are queued instead of issued if a queue has been stopped. Reported-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Cc: <stable@vger.kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: add bio_iov_iter_get_pages()Kent Overstreet2016-11-021-0/+49
| | | | | | | | | | | | | | This is a helper that pins down a range from an iov_iter and adds it to a bio without requiring a separate memory allocation for the page array. It will be used for upcoming direct I/O implementations for block devices and iomap based file systems. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> [hch: ported to the iov_iter interface, renamed and added comments. All blame should be directed to me and all fame should go to Kent after this!] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* block,fs: use REQ_* flags directlyChristoph Hellwig2016-11-011-2/+2
| | | | | | | | | Remove the WRITE_* and READ_SYNC wrappers, and just use the flags directly. Where applicable this also drops usage of the bio_set_op_attrs wrapper. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: replace REQ_NOIDLE with REQ_IDLEChristoph Hellwig2016-11-011-3/+8
| | | | | | | | | | | | | | Noidle should be the default for writes as seen by all the compounds definitions in fs.h using it. In fact only direct I/O really should be using NODILE, so turn the whole flag around to get the defaults right, which will make our life much easier especially onces the WRITE_* defines go away. This assumes all the existing "raw" users of REQ_SYNC for writes want noidle behavior, which seems to be spot on from a quick audit. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* cfq-iosched: use op_is_sync instead of opencoding itChristoph Hellwig2016-11-011-12/+4
| | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: better op and flags encodingChristoph Hellwig2016-10-287-95/+69
| | | | | | | | | | | | | | | | | | | Now that we don't need the common flags to overflow outside the range of a 32-bit type we can encode them the same way for both the bio and request fields. This in addition allows us to place the operation first (and make some room for more ops while we're at it) and to stop having to shift around the operation values. In addition this allows passing around only one value in the block layer instead of two (and eventuall also in the file systems, but we can do that later) and thus clean up a lot of code. Last but not least this allows decreasing the size of the cmd_flags field in struct request to 32-bits. Various functions passing this value could also be updated, but I'd like to avoid the churn for now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: split out request-only flags into a new namespaceChristoph Hellwig2016-10-289-77/+78
| | | | | | | | | | | | | | | | A lot of the REQ_* flags are only used on struct requests, and only of use to the block layer and a few drivers that dig into struct request internals. This patch adds a new req_flags_t rq_flags field to struct request for them, and thus dramatically shrinks the number of common requests. It also removes the unfortunate situation where we have to fit the fields from the same enum into 32 bits for struct bio and 64 bits for struct request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: replace REQ_THROTTLED with a bio flagChristoph Hellwig2016-10-281-5/+5
| | | | | | | | | It's the last bio-only REQ_* flag, and we have space for it in the bio bi_flags field. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: remove bio_is_rwChristoph Hellwig2016-10-281-1/+1
| | | | | | | | | | With the addition of the zoned operations the tests in this function became incorrect. But I think it's much better to just open code the allow operations in the only caller anyway. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: get rid of confusing blk_map_ctx structureJens Axboe2016-10-271-13/+5
| | | | | | | | We can just use struct blk_mq_alloc_data - it has a few more members, but we allocate it further down the stack anyway. So this cleans up the code, and reduces the stack overhead a bit. Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-mq: update hardware and software queues for sleeping allocJens Axboe2016-10-271-3/+3
| | | | | | | | | | | | | | If we end up sleeping due to running out of requests, we should update the hardware and software queues in the map ctx structure. Otherwise we could end up having rq->mq_ctx point to the pre-sleep context, and risk corrupting ctx->rq_list since we'll be grabbing the wrong lock when inserting the request. Reported-by: Dave Jones <davej@codemonkey.org.uk> Reported-by: Chris Mason <clm@fb.com> Tested-by: Chris Mason <clm@fb.com> Fixes: 63581af3f31e ("blk-mq: remove non-blocking pass in blk_mq_map_request") Signed-off-by: Jens Axboe <axboe@fb.com>
* block: zoned: fix harmless maybe-uninitialized warningArnd Bergmann2016-10-241-4/+2
| | | | | | | | | | | | | | | | | | | | | The blkdev_report_zones produces a harmless warning when -Wmaybe-uninitialized is set, after gcc gets a little confused about the multiple 'goto' here: block/blk-zoned.c: In function 'blkdev_report_zones': block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in this function [-Werror=maybe-uninitialized] Moving the assignment to nr_zones makes this a little simpler while also avoiding the warning reliably. I'm removing the extraneous initialization of 'int ret' in the same patch, as that is semi-related and could cause an uninitialized use of that variable to not produce a warning. Fixes: 6a0cb1bc106f ("block: Implement support for zoned block devices") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-zoned: implement ioctlsShaun Tancheff2016-10-182-0/+97
| | | | | | | | | | | | | | | | | | | Adds the new BLKREPORTZONE and BLKRESETZONE ioctls for respectively obtaining the zone configuration of a zoned block device and resetting the write pointer of sequential zones of a zoned block device. The BLKREPORTZONE ioctl maps directly to a single call of the function blkdev_report_zones. The zone information result is passed as an array of struct blk_zone identical to the structure used internally for processing the REQ_OP_ZONE_REPORT operation. The BLKRESETZONE ioctl maps to a single call of the blkdev_reset_zones function. Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: Implement support for zoned block devicesHannes Reinecke2016-10-183-0/+266
| | | | | | | | | | | | | | | | | | | | | | | | Implement zoned block device zone information reporting and reset. Zone information are reported as struct blk_zone. This implementation does not differentiate between host-aware and host-managed device models and is valid for both. Two functions are provided: blkdev_report_zones for discovering the zone configuration of a zoned block device, and blkdev_reset_zones for resetting the write pointer of sequential zones. The helper function blk_queue_zone_size and bdev_zone_size are also provided for, as the name suggest, obtaining the zone size (in 512B sectors) of the zones of the device. Signed-off-by: Hannes Reinecke <hare@suse.de> [Damien: * Removed the zone cache * Implement report zones operation based on earlier proposal by Shaun Tancheff <shaun.tancheff@seagate.com>] Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: Define zoned block device operationsShaun Tancheff2016-10-181-0/+4
| | | | | | | | | | | | | | Define REQ_OP_ZONE_REPORT and REQ_OP_ZONE_RESET for handling zones of host-managed and host-aware zoned block devices. With with these two new operations, the total number of operations defined reaches 8 and still fits with the 3 bits definition of REQ_OP_BITS. Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: update chunk_sectors in blk_stack_limits()Hannes Reinecke2016-10-181-0/+4
| | | | | | | | | | Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* blk-sysfs: Add 'chunk_sectors' to sysfs attributesHannes Reinecke2016-10-181-0/+11
| | | | | | | | | | | | | | | | The queue limits already have a 'chunk_sectors' setting, so we should be presenting it via sysfs. Signed-off-by: Hannes Reinecke <hare@suse.de> [Damien: Updated Documentation/ABI/testing/sysfs-block] Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* block: Add 'zoned' queue limitDamien Le Moal2016-10-182-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | Add the zoned queue limit to indicate the zoning model of a block device. Defined values are 0 (BLK_ZONED_NONE) for regular block devices, 1 (BLK_ZONED_HA) for host-aware zone block devices and 2 (BLK_ZONED_HM) for host-managed zone block devices. The standards defined drive managed model is not defined here since these block devices do not provide any command for accessing zone information. Drive managed model devices will be reported as BLK_ZONED_NONE. The helper functions blk_queue_zoned_model and bdev_zoned_model return the zoned limit and the functions blk_queue_is_zoned and bdev_is_zoned return a boolean for callers to test if a block device is zoned. The zoned attribute is also exported as a string to applications via sysfs. BLK_ZONED_NONE shows as "none", BLK_ZONED_HA as "host-aware" and BLK_ZONED_HM as "host-managed". Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge tag 'gcc-plugins-v4.9-rc1' of ↵Linus Torvalds2016-10-151-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc plugins update from Kees Cook: "This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals" * tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: latent_entropy: Mark functions with __latent_entropy gcc-plugins: Add latent_entropy plugin
| * latent_entropy: Mark functions with __latent_entropyEmese Revfy2016-10-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The __latent_entropy gcc attribute can be used only on functions and variables. If it is on a function then the plugin will instrument it for gathering control-flow entropy. If the attribute is on a variable then the plugin will initialize it with random contents. The variable must be an integer, an integer array type or a structure with integer fields. These specific functions have been selected because they are init functions (to help gather boot-time entropy), are called at unpredictable times, or they have variable loops, each of which provide some level of latent entropy. Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: expanded commit message] Signed-off-by: Kees Cook <keescook@chromium.org>
* | Merge branch 'for-4.9' of ↵Linus Torvalds2016-10-141-3/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - tracepoints for basic cgroup management operations added - kernfs and cgroup path formatting functions updated to behave in the style of strlcpy() - non-critical bug fixes * 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL cgroup: fix error handling regressions in proc_cgroup_show() and cgroup_release_agent() cpuset: fix error handling regression in proc_cpuset_show() cgroup: add tracepoints for basic operations cgroup: make cgroup_path() and friends behave in the style of strlcpy() kernfs: remove kernfs_path_len() kernfs: make kernfs_path*() behave in the style of strlcpy() kernfs: add dummy implementation of kernfs_path_from_node()
| * | blkcg: Unlock blkcg_pol_mutex only once when cpd == NULLBart Van Assche2016-09-301-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Unlocking a mutex twice is wrong. Hence modify blkcg_policy_register() such that blkcg_pol_mutex is unlocked once if cpd == NULL. This patch avoids that smatch reports the following error: block/blk-cgroup.c:1378: blkcg_policy_register() error: double unlock 'mutex:&blkcg_pol_mutex' Fixes: 06b285bd1125 ("blkcg: fix blkcg_policy_data allocation bug") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> # v4.2+ Signed-off-by: Tejun Heo <tj@kernel.org>
* | | block: require write_same and discard requests align to logical block sizeDarrick J. Wong2016-10-111-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make sure that the offset and length arguments that we're using to construct WRITE SAME and DISCARD requests are actually aligned to the logical block size. Failure to do this causes other errors in other parts of the block layer or the SCSI layer because disks don't support partial logical block writes. Link: http://lkml.kernel.org/r/147518379026.22791.4437508871355153928.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Mike Snitzer <snitzer@redhat.com> # tweaked header Cc: Brian Foster <bfoster@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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