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* block: Fix transfer when chunk sectors exceeds maxKeith Busch2018-06-261-2/+2
| | | | | | | | | | | | | A device may have boundary restrictions where the number of sectors between boundaries exceeds its max transfer size. In this case, we need to cap the max size to the smaller of the two limits. Reported-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com> Tested-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com> Cc: <stable@vger.kernel.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remov blk_queue_invalidate_tagsChristoph Hellwig2018-06-151-2/+0
| | | | | | | | This function is entirely unused, so remove it and the tag_queue_busy member of struct request_queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: don't time out requests again that are in the timeout handlerChristoph Hellwig2018-06-141-0/+2
| | | | | | | | | | | | We can currently call the timeout handler again on a request that has already been handed over to the timeout handler. Prevent that with a new flag. Fixes: 12f5b931 ("blk-mq: Remove generation seqeunce") Reported-by: Andrew Randrianasulu <randrianasulu@gmail.com> Tested-by: Andrew Randrianasulu <randrianasulu@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: convert bounce, q->bio_split to bioset_init()/mempool_init()Kent Overstreet2018-05-301-1/+1
| | | | | | | | Convert the core block functionality to embedded bio sets. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move ->timeout request memberJens Axboe2018-05-291-2/+2
| | | | | | | | | After the recent timeout handling changes, we have two holes in the struct. Move the timeout near the deadline, killing both, and moving related members closer together. On my config on x86-64, this shrinks struct request from 312 to 304 bytes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: document the blk_eh_timer_return valuesChristoph Hellwig2018-05-291-2/+2
| | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove BLK_EH_HANDLEDChristoph Hellwig2018-05-291-1/+0
| | | | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: rename BLK_EH_NOT_HANDLED to BLK_EH_DONEChristoph Hellwig2018-05-291-1/+1
| | | | | | | | | | | The BLK_EH_NOT_HANDLED implies nothing happen, but very often that is not what is happening - instead the driver already completed the command. Fix the symbolic name to reflect that a little better. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: Remove generation seqeunceKeith Busch2018-05-291-23/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch simplifies the timeout handling by relying on the request reference counting to ensure the iterator is operating on an inflight and truly timed out request. Since the reference counting prevents the tag from being reallocated, the block layer no longer needs to prevent drivers from completing their requests while the timeout handler is operating on it: a driver completing a request is allowed to proceed to the next state without additional syncronization with the block layer. This also removes any need for generation sequence numbers since the request lifetime is prevented from being reallocated as a new sequence while timeout handling is operating on it. To enables this a refcount is added to struct request so that request users can be sure they're operating on the same request without it changing while they're processing it. The request's tag won't be released for reuse until both the timeout handler and the completion are done with it. Signed-off-by: Keith Busch <keith.busch@intel.com> [hch: slight cleanups, added back submission side hctx lock, use cmpxchg for completions] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: sanitize blk_get_request calling conventionsChristoph Hellwig2018-05-141-4/+1
| | | | | | | | | Switch everyone to blk_get_request_flags, and then rename blk_get_request_flags to blk_get_request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: consolidate struct request timestamp fieldsOmar Sandoval2018-05-091-36/+2
| | | | | | | | | | | | | | | | Currently, struct request has four timestamp fields: - A start time, set at get_request time, in jiffies, used for iostats - An I/O start time, set at start_request time, in ktime nanoseconds, used for blk-stats (i.e., wbt, kyber, hybrid polling) - Another start time and another I/O start time, used for cfq and bfq These can all be consolidated into one start time and one I/O start time, both in ktime nanoseconds, shaving off up to 16 bytes from struct request depending on the kernel config. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: use ktime_get_ns() instead of sched_clock() for cfq and bfqOmar Sandoval2018-05-091-15/+6
| | | | | | | | | | | cfq and bfq have some internal fields that use sched_clock() which can trivially use ktime_get_ns() instead. Their timestamp fields in struct request can also use ktime_get_ns(), which resolves the 8 year old comment added by commit 28f4197e5d47 ("block: disable preemption before using sched_clock()"). Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: get rid of struct blk_issue_statOmar Sandoval2018-05-091-8/+18
| | | | | | | | | | | | | | | struct blk_issue_stat squashes three things into one u64: - The time the driver started working on a request - The original size of the request (for the io.low controller) - Flags for writeback throttling It turns out that on x86_64, we have a 4 byte hole in struct request which we can fill with the non-timestamp fields from blk_issue_stat, simplifying things quite a bit. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge tag 'scsi-fixes' of ↵Linus Torvalds2018-04-251-0/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi Pull SCSI fixes from James Bottomley: "Eight bug fixes, one spelling update and one tracepoint addition. The most serious is probably the mptsas write same fix because it means anyone using these controllers sees errors when modern filesystems try to issue discards" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: scsi: target: fix crash with iscsi target and dvd scsi: sd_zbc: Avoid that resetting a zone fails sporadically scsi: sd: Defer spinning up drive while SANITIZE is in progress scsi: megaraid_sas: Do not log an error if FW successfully initializes. scsi: ufs: add trace event for ufs upiu scsi: core: remove reference to scsi_show_extd_sense() scsi: mptsas: Disable WRITE SAME scsi: fnic: fix spelling mistake in fnic stats "Abord" -> "Abort" scsi: scsi_debug: IMMED related delay adjustments scsi: iscsi: respond to netlink with unicast when appropriate
| * scsi: sd_zbc: Avoid that resetting a zone fails sporadicallyBart Van Assche2018-04-191-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since SCSI scanning occurs asynchronously, since sd_revalidate_disk() is called from sd_probe_async() and since sd_revalidate_disk() calls sd_zbc_read_zones() it can happen that sd_zbc_read_zones() is called concurrently with blkdev_report_zones() and/or blkdev_reset_zones(). That can cause these functions to fail with -EIO because sd_zbc_read_zones() e.g. sets q->nr_zones to zero before restoring it to the actual value, even if no drive characteristics have changed. Avoid that this can happen by making the following changes: - Protect the code that updates zone information with blk_queue_enter() and blk_queue_exit(). - Modify sd_zbc_setup_seq_zones_bitmap() and sd_zbc_setup() such that these functions do not modify struct scsi_disk before all zone information has been obtained. Note: since commit 055f6e18e08f ("block: Make q_usage_counter also track legacy requests"; kernel v4.15) the request queue freezing mechanism also affects legacy request queues. Fixes: 89d947561077 ("sd: Implement support for ZBC devices") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: stable@vger.kernel.org # v4.16 Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
* | block: add blk_queue_fua() helper functionDave Chinner2018-04-181-0/+1
|/ | | | | | | | So we can check FUA support status from the iomap direct IO code. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Move SECTOR_SIZE and SECTOR_SHIFT definitions into <linux/blkdev.h>Bart Van Assche2018-03-171-11/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It happens often while I'm preparing a patch for a block driver that I'm wondering: is a definition of SECTOR_SIZE and/or SECTOR_SHIFT available for this driver? Do I have to introduce definitions of these constants before I can use these constants? To avoid this confusion, move the existing definitions of SECTOR_SIZE and SECTOR_SHIFT into the <linux/blkdev.h> header file such that these become available for all block drivers. Make the SECTOR_SIZE definition in the uapi msdos_fs.h header file conditional to avoid that including that header file after <linux/blkdev.h> causes the compiler to complain about a SECTOR_SIZE redefinition. Note: the SECTOR_SIZE / SECTOR_SHIFT / SECTOR_BITS definitions have not been removed from uapi header files nor from NAND drivers in which these constants are used for another purpose than converting block layer offsets and sizes into a number of sectors. Cc: David S. Miller <davem@davemloft.net> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Move the queue_flag_*() functions from a public into a private header ↵Bart Van Assche2018-03-081-69/+0
| | | | | | | | | | | | | | | | file This patch helps to avoid that new code gets introduced in block drivers that manipulates queue flags without holding the queue lock when that lock should be held. Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Complain if queue_flag_(set|clear)_unlocked() is abusedBart Van Assche2018-03-081-0/+6
| | | | | | | | | | | | | | | Since it is not safe to use queue_flag_(set|clear)_unlocked() without holding the queue lock after the sysfs entries for a queue have been created, complain if this happens. Cc: Mike Snitzer <snitzer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Introduce blk_queue_flag_{set,clear,test_and_{set,clear}}()Bart Van Assche2018-03-081-0/+5
| | | | | | | | | | | | | | | Introduce functions that modify the queue flags and that protect these modifications with the request queue lock. Except for moving one wake_up_all() call from inside to outside a critical section, this patch does not change any functionality. Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Reorder the queue flag manipulation function definitionsBart Van Assche2018-03-081-11/+11
| | | | | | | | | | | | | | | | Move the definition of queue_flag_clear_unlocked() up and move the definition of queue_in_flight() down such that all queue flag manipulation function definitions become contiguous. This patch does not change any functionality. Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Add 'lock' as third argument to blk_alloc_queue_node()Bart Van Assche2018-02-281-1/+2
| | | | | | | | | | | | This patch does not change any functionality. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix a typo in comment of BLK_MQ_POLL_STATS_BKTSMinwoo Im2018-02-151-1/+1
| | | | | | | | | Update comment typo _consisitent_ to _consistent_ from following commit. commit 0206319fdfee ("blk-mq: Fix poll_stat for new size-based bucketing.") Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'for-4.16/block' of git://git.kernel.dk/linux-blockLinus Torvalds2018-01-291-17/+155
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block updates from Jens Axboe: "This is the main pull request for block IO related changes for the 4.16 kernel. Nothing major in this pull request, but a good amount of improvements and fixes all over the map. This contains: - BFQ improvements, fixes, and cleanups from Angelo, Chiara, and Paolo. - Support for SMR zones for deadline and mq-deadline from Damien and Christoph. - Set of fixes for bcache by way of Michael Lyle, including fixes from himself, Kent, Rui, Tang, and Coly. - Series from Matias for lightnvm with fixes from Hans Holmberg, Javier, and Matias. Mostly centered around pblk, and the removing rrpc 1.2 in preparation for supporting 2.0. - A couple of NVMe pull requests from Christoph. Nothing major in here, just fixes and cleanups, and support for command tracing from Johannes. - Support for blk-throttle for tracking reads and writes separately. From Joseph Qi. A few cleanups/fixes also for blk-throttle from Weiping. - Series from Mike Snitzer that enables dm to register its queue more logically, something that's alwways been problematic on dm since it's a stacked device. - Series from Ming cleaning up some of the bio accessor use, in preparation for supporting multipage bvecs. - Various fixes from Ming closing up holes around queue mapping and quiescing. - BSD partition fix from Richard Narron, fixing a problem where we can't mount newer (10/11) FreeBSD partitions. - Series from Tejun reworking blk-mq timeout handling. The previous scheme relied on atomic bits, but it had races where we would think a request had timed out if it to reused at the wrong time. - null_blk now supports faking timeouts, to enable us to better exercise and test that functionality separately. From me. - Kill the separate atomic poll bit in the request struct. After this, we don't use the atomic bits on blk-mq anymore at all. From me. - sgl_alloc/free helpers from Bart. - Heavily contended tag case scalability improvement from me. - Various little fixes and cleanups from Arnd, Bart, Corentin, Douglas, Eryu, Goldwyn, and myself" * 'for-4.16/block' of git://git.kernel.dk/linux-block: (186 commits) block: remove smart1,2.h nvme: add tracepoint for nvme_complete_rq nvme: add tracepoint for nvme_setup_cmd nvme-pci: introduce RECONNECTING state to mark initializing procedure nvme-rdma: remove redundant boolean for inline_data nvme: don't free uuid pointer before printing it nvme-pci: Suspend queues after deleting them bsg: use pr_debug instead of hand crafted macros blk-mq-debugfs: don't allow write on attributes with seq_operations set nvme-pci: Fix queue double allocations block: Set BIO_TRACE_COMPLETION on new bio during split blk-throttle: use queue_is_rq_based block: Remove kblockd_schedule_delayed_work{,_on}() blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces unintended delays blk-mq: Rename blk_mq_request_direct_issue() into blk_mq_request_issue_directly() lib/scatterlist: Fix chaining support in sgl_alloc_order() blk-throttle: track read and write request individually block: add bdev_read_only() checks to common helpers block: fail op_is_write() requests to read-only partitions blk-throttle: export io_serviced_recursive, io_service_bytes_recursive ...
| * block: Remove kblockd_schedule_delayed_work{,_on}()Bart Van Assche2018-01-191-2/+0
| | | | | | | | | | | | | | | | | | The previous patch removed all users of these two functions. Hence also remove the functions themselves. Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: rearrange a few request fields for better cache layoutJens Axboe2018-01-101-13/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move completion related items (like the call single data) near the end of the struct, instead of mixing them in with the initial queueing related fields. Move queuelist below the bio structures. Then we have all queueing related bits in the first cache line. This yields a 1.5-2% increase in IOPS for a null_blk test, both for sync and for high thread count access. Sync test goes form 975K to 992K, 32-thread case from 20.8M to 21.2M IOPS. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: convert REQ_ATOM_COMPLETE to stealing rq->__deadline bitJens Axboe2018-01-101-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | We only have one atomic flag left. Instead of using an entire unsigned long for that, steal the bottom bit of the deadline field that we already reserved. Remove ->atomic_flags, since it's now unused. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: add accessors for setting/querying request deadlineJens Axboe2018-01-101-1/+3
| | | | | | | | | | | | | | | | | | | | | | We reduce the resolution of request expiry, but since we're already using jiffies for this where resolution depends on the kernel configuration and since the timeout resolution is coarse anyway, that should be fine. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: remove REQ_ATOM_POLL_SLEPTJens Axboe2018-01-101-0/+2
| | | | | | | | | | | | | | | | | | | | | | We don't need this to be an atomic flag, it can be a regular flag. We either end up on the same CPU for the polling, in which case the state is sane, or we did the sleep which would imply the needed barrier to ensure we see the right state. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mqTejun Heo2018-01-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After the recent updates to use generation number and state based synchronization, blk-mq no longer depends on REQ_ATOM_COMPLETE except to avoid firing the same timeout multiple times. Remove all REQ_ATOM_COMPLETE usages and use a new rq_flags flag RQF_MQ_TIMEOUT_EXPIRED to avoid firing the same timeout multiple times. This removes atomic bitops from hot paths too. v2: Removed blk_clear_rq_complete() from blk_mq_rq_timed_out(). v3: Added RQF_MQ_TIMEOUT_EXPIRED flag. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: "jianchao.wang" <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * blk-mq: replace timeout synchronization with a RCU and generation based schemeTejun Heo2018-01-091-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, blk-mq timeout path synchronizes against the usual issue/completion path using a complex scheme involving atomic bitflags, REQ_ATOM_*, memory barriers and subtle memory coherence rules. Unfortunately, it contains quite a few holes. There's a complex dancing around REQ_ATOM_STARTED and REQ_ATOM_COMPLETE between issue/completion and timeout paths; however, they don't have a synchronization point across request recycle instances and it isn't clear what the barriers add. blk_mq_check_expired() can easily read STARTED from N-2'th iteration, deadline from N-1'th, blk_mark_rq_complete() against Nth instance. In fact, it's pretty easy to make blk_mq_check_expired() terminate a later instance of a request. If we induce 5 sec delay before time_after_eq() test in blk_mq_check_expired(), shorten the timeout to 2s, and issue back-to-back large IOs, blk-mq starts timing out requests spuriously pretty quickly. Nothing actually timed out. It just made the call on a recycle instance of a request and then terminated a later instance long after the original instance finished. The scenario isn't theoretical either. This patch replaces the broken synchronization mechanism with a RCU and generation number based one. 1. Each request has a u64 generation + state value, which can be updated only by the request owner. Whenever a request becomes in-flight, the generation number gets bumped up too. This provides the basis for the timeout path to distinguish different recycle instances of the request. Also, marking a request in-flight and setting its deadline are protected with a seqcount so that the timeout path can fetch both values coherently. 2. The timeout path fetches the generation, state and deadline. If the verdict is timeout, it records the generation into a dedicated request abortion field and does RCU wait. 3. The completion path is also protected by RCU (from the previous patch) and checks whether the current generation number and state match the abortion field. If so, it skips completion. 4. The timeout path, after RCU wait, scans requests again and terminates the ones whose generation and state still match the ones requested for abortion. By now, the timeout path knows that either the generation number and state changed if it lost the race or the completion will yield to it and can safely timeout the request. While it's more lines of code, it's conceptually simpler, doesn't depend on direct use of subtle memory ordering or coherence, and hopefully doesn't terminate the wrong instance. While this change makes REQ_ATOM_COMPLETE synchronization unnecessary between issue/complete and timeout paths, REQ_ATOM_COMPLETE isn't removed yet as it's still used in other places. Future patches will move all state tracking to the new mechanism and remove all bitops in the hot paths. Note that this patch adds a comment explaining a race condition in BLK_EH_RESET_TIMER path. The race has always been there and this patch doesn't change it. It's just documenting the existing race. v2: - Fixed BLK_EH_RESET_TIMER handling as pointed out by Jianchao. - s/request->gstate_seqc/request->gstate_seq/ as suggested by Peter. - READ_ONCE() added in blk_mq_rq_update_state() as suggested by Peter. v3: - Fixed possible extended seqcount / u64_stats_sync read looping spotted by Peter. - MQ_RQ_IDLE was incorrectly being set in complete_request instead of free_request. Fixed. v4: - Rebased on top of hctx_lock() refactoring patch. - Added comment explaining the use of hctx_lock() in completion path. v5: - Added comments requested by Bart. - Note the addition of BLK_EH_RESET_TIMER race condition in the commit message. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: "jianchao.wang" <jianchao.w.wang@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Bart Van Assche <Bart.VanAssche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: introduce zoned block devices zone write lockingChristoph Hellwig2018-01-051-0/+111
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Components relying only on the request_queue structure for accessing block devices (e.g. I/O schedulers) have a limited knowledged of the device characteristics. In particular, the device capacity cannot be easily discovered, which for a zoned block device also result in the inability to easily know the number of zones of the device (the zone size is indicated by the chunk_sectors field of the queue limits). Introduce the nr_zones field to the request_queue structure to simplify access to this information. Also, add the bitmap seq_zone_bitmap which indicates which zones of the device are sequential zones (write preferred or write required) and the bitmap seq_zones_wlock which indicates if a zone is write locked, that is, if a write request targeting a zone was dispatched to the device. These fields are initialized by the low level block device driver (sd.c for ZBC/ZAC disks). They are not initialized by stacking drivers (device mappers) handling zoned block devices (e.g. dm-linear). Using this, I/O schedulers can introduce zone write locking to control request dispatching to a zoned block device and avoid write request reordering by limiting to at most a single write request per zone outside of the scheduler at any time. Based on previous patches from Damien Le Moal. Signed-off-by: Christoph Hellwig <hch@lst.de> [Damien] * Fixed comments and identation in blkdev.h * Changed helper functions * Fixed this commit message Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: unalign call_single_data in struct requestJens Axboe2017-12-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | A previous change blindly added massive alignment to the call_single_data structure in struct request. This ballooned it in size from 296 to 320 bytes on my setup, for no valid reason at all. Use the unaligned struct __call_single_data variant instead. Fixes: 966a967116e69 ("smp: Avoid using two cache lines for struct call_single_data") Cc: stable@vger.kernel.org # v4.14 Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: fix blk_rq_append_bioJens Axboe2017-12-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit caa4b02476e3(blk-map: call blk_queue_bounce from blk_rq_append_bio) moves blk_queue_bounce() into blk_rq_append_bio(), but don't consider the fact that the bounced bio becomes invisible to caller since the parameter type is 'struct bio *'. Make it a pointer to a pointer to a bio, so the caller sees the right bio also after a bounce. Fixes: caa4b02476e3 ("blk-map: call blk_queue_bounce from blk_rq_append_bio") Cc: Christoph Hellwig <hch@lst.de> Reported-by: Michele Ballabio <barra_cuda@katamail.com> (handling failure of blk_rq_append_bio(), only call bio_get() after blk_rq_append_bio() returns OK) Tested-by: Michele Ballabio <barra_cuda@katamail.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: don't let passthrough IO go into .make_request_fn()Ming Lei2017-12-181-2/+19
|/ | | | | | | | | | | | | | | | | | | | Commit a8821f3f3("block: Improvements to bounce-buffer handling") tries to make sure that the bio to .make_request_fn won't exceed BIO_MAX_PAGES, but ignores that passthrough I/O can use blk_queue_bounce() too. Especially, passthrough IO may not be sector-aligned, and the check of 'sectors < bio_sectors(*bio_orig)' inside __blk_queue_bounce() may become true even though the max bvec number doesn't exceed BIO_MAX_PAGES, then cause the bio splitted, and the original passthrough bio is submited to generic_make_request(). This patch fixes this issue by checking if the bio is passthrough IO, and use bio_kmalloc() to allocate the cloned passthrough bio. Cc: NeilBrown <neilb@suse.com> Fixes: a8821f3f3("block: Improvements to bounce-buffer handling") Tested-by: Michele Ballabio <barra_cuda@katamail.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-blockLinus Torvalds2017-11-141-19/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block layer updates from Jens Axboe: "This is the main pull request for block storage for 4.15-rc1. Nothing out of the ordinary in here, and no API changes or anything like that. Just various new features for drivers, core changes, etc. In particular, this pull request contains: - A patch series from Bart, closing the whole on blk/scsi-mq queue quescing. - A series from Christoph, building towards hidden gendisks (for multipath) and ability to move bio chains around. - NVMe - Support for native multipath for NVMe (Christoph). - Userspace notifications for AENs (Keith). - Command side-effects support (Keith). - SGL support (Chaitanya Kulkarni) - FC fixes and improvements (James Smart) - Lots of fixes and tweaks (Various) - bcache - New maintainer (Michael Lyle) - Writeback control improvements (Michael) - Various fixes (Coly, Elena, Eric, Liang, et al) - lightnvm updates, mostly centered around the pblk interface (Javier, Hans, and Rakesh). - Removal of unused bio/bvec kmap atomic interfaces (me, Christoph) - Writeback series that fix the much discussed hundreds of millions of sync-all units. This goes all the way, as discussed previously (me). - Fix for missing wakeup on writeback timer adjustments (Yafang Shao). - Fix laptop mode on blk-mq (me). - {mq,name} tupple lookup for IO schedulers, allowing us to have alias names. This means you can use 'deadline' on both !mq and on mq (where it's called mq-deadline). (me). - blktrace race fix, oopsing on sg load (me). - blk-mq optimizations (me). - Obscure waitqueue race fix for kyber (Omar). - NBD fixes (Josef). - Disable writeback throttling by default on bfq, like we do on cfq (Luca Miccio). - Series from Ming that enable us to treat flush requests on blk-mq like any other request. This is a really nice cleanup. - Series from Ming that improves merging on blk-mq with schedulers, getting us closer to flipping the switch on scsi-mq again. - BFQ updates (Paolo). - blk-mq atomic flags memory ordering fixes (Peter Z). - Loop cgroup support (Shaohua). - Lots of minor fixes from lots of different folks, both for core and driver code" * 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits) nvme: fix visibility of "uuid" ns attribute blk-mq: fixup some comment typos and lengths ide: ide-atapi: fix compile error with defining macro DEBUG blk-mq: improve tag waiting setup for non-shared tags brd: remove unused brd_mutex blk-mq: only run the hardware queue if IO is pending block: avoid null pointer dereference on null disk fs: guard_bio_eod() needs to consider partitions xtensa/simdisk: fix compile error nvme: expose subsys attribute to sysfs nvme: create 'slaves' and 'holders' entries for hidden controllers block: create 'slaves' and 'holders' entries for hidden gendisks nvme: also expose the namespace identification sysfs files for mpath nodes nvme: implement multipath access to nvme subsystems nvme: track shared namespaces nvme: introduce a nvme_ns_ids structure nvme: track subsystems block, nvme: Introduce blk_mq_req_flags_t block, scsi: Make SCSI quiesce and resume work reliably block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag ...
| * block, nvme: Introduce blk_mq_req_flags_tBart Van Assche2017-11-101-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Several block layer and NVMe core functions accept a combination of BLK_MQ_REQ_* flags through the 'flags' argument but there is no verification at compile time whether the right type of block layer flags is passed. Make it possible for sparse to verify this. This patch does not change any functionality. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: linux-nvme@lists.infradead.org Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block, scsi: Make SCSI quiesce and resume work reliablyBart Van Assche2017-11-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The contexts from which a SCSI device can be quiesced or resumed are: * Writing into /sys/class/scsi_device/*/device/state. * SCSI parallel (SPI) domain validation. * The SCSI device power management methods. See also scsi_bus_pm_ops. It is essential during suspend and resume that neither the filesystem state nor the filesystem metadata in RAM changes. This is why while the hibernation image is being written or restored that SCSI devices are quiesced. The SCSI core quiesces devices through scsi_device_quiesce() and scsi_device_resume(). In the SDEV_QUIESCE state execution of non-preempt requests is deferred. This is realized by returning BLKPREP_DEFER from inside scsi_prep_state_check() for quiesced SCSI devices. Avoid that a full queue prevents power management requests to be submitted by deferring allocation of non-preempt requests for devices in the quiesced state. This patch has been tested by running the following commands and by verifying that after each resume the fio job was still running: for ((i=0; i<10; i++)); do ( cd /sys/block/md0/md && while true; do [ "$(<sync_action)" = "idle" ] && echo check > sync_action sleep 1 done ) & pids=($!) for d in /sys/class/block/sd*[a-z]; do bdev=${d#/sys/class/block/} hcil=$(readlink "$d/device") hcil=${hcil#../../../} echo 4 > "$d/queue/nr_requests" echo 1 > "/sys/class/scsi_device/$hcil/device/queue_depth" fio --name="$bdev" --filename="/dev/$bdev" --buffered=0 --bs=512 \ --rw=randread --ioengine=libaio --numjobs=4 --iodepth=16 \ --iodepth_batch=1 --thread --loops=$((2**31)) & pids+=($!) done sleep 1 echo "$(date) Hibernating ..." >>hibernate-test-log.txt systemctl hibernate sleep 10 kill "${pids[@]}" echo idle > /sys/block/md0/md/sync_action wait echo "$(date) Done." >>hibernate-test-log.txt done Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name> References: "I/O hangs after resuming from suspend-to-ram" (https://marc.info/?l=linux-block&m=150340235201348). Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Martin Steigerwald <martin@lichtvoll.de> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flagBart Van Assche2017-11-101-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This flag will be used in the next patch to let the block layer core know whether or not a SCSI request queue has been quiesced. A quiesced SCSI queue namely only processes RQF_PREEMPT requests. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Martin Steigerwald <martin@lichtvoll.de> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: Ming Lei <ming.lei@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: Introduce blk_get_request_flags()Bart Van Assche2017-11-101-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A side effect of this patch is that the GFP mask that is passed to several allocation functions in the legacy block layer is changed from GFP_KERNEL into __GFP_DIRECT_RECLAIM. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Martin Steigerwald <martin@lichtvoll.de> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: pass full fmode_t to blk_verify_commandChristoph Hellwig2017-11-101-1/+1
| | | | | | | | | | | | | | Use the obvious calling convention. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: add a poll_fn callback to struct request_queueChristoph Hellwig2017-11-031-1/+3
| | | | | | | | | | | | | | | | | | That we we can also poll non blk-mq queues. Mostly needed for the NVMe multipath code, but could also be useful elsewhere. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: add a blk_steal_bios helperChristoph Hellwig2017-11-031-0/+2
| | | | | | | | | | | | | | | | | | | | This helpers allows to bounce steal the uncompleted bios from a request so that they can be reissued on another path. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: provide a direct_make_request helperChristoph Hellwig2017-11-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | This helper allows reinserting a bio into a new queue without much overhead, but requires all queue limits to be the same for the upper and lower queues, and it does not provide any recursion preventions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Javier González <javier@cnexlabs.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * fs/block_dev: remove vfs_msg() interfaceRakesh Pandit2017-10-121-11/+0
| | | | | | | | | | | | | | | | | | Replaced by pr_err usage in commit ef51042472f5 ("block, dax: move "select DAX" from BLOCK to FS_DAX") Signed-off-by: Rakesh Pandit <rakesh@tuxera.com> Acked-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: remove QUEUE_FLAG_STACKABLEChristoph Hellwig2017-10-051-5/+0
| | | | | | | | | | | | | | | | | | We already have a queue_is_rq_based helper to check if a request_queue is request based, so we can remove the flag for it. Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* blktrace: Fix potential deadlock between delete & sysfs opsWaiman Long2017-09-251-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-blockLinus Torvalds2017-09-071-31/+29
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ...
| * block: remove unused syncfull/asyncfull queue flagsJens Axboe2017-08-101-31/+29
| | | | | | | | | | | | | | | | We haven't used these in years, but somehow the definitions still remained. Kill them, and renumber the QUEUE_FLAG_ space. We had a hole in the beginning of the space, too. Signed-off-by: Jens Axboe <axboe@kernel.dk>
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