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2019-06-20blk-cgroup: factor out a helper to read rwstat counterChristoph Hellwig
Trying to break up the crazy statements to something readable. Also switch to an unsigned counter as it can't ever turn negative. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: mark blk_rq_bio_prep as inlineChristoph Hellwig
This function just has a few trivial assignments, has two callers with one of them being in the fastpath. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: untangle the end of blk_bio_segment_splitChristoph Hellwig
Now that we don't need to assign the front/back segment sizes, we can duplicating the segs assignment for the split vs no-split case and remove a whole chunk of boilerplate code. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: simplify blk_recalc_rq_segmentsChristoph Hellwig
Return the segement and let the callers assign them, which makes the code a littler more obvious. Also pass the request instead of q plus bio chain, allowing for the use of rq_for_each_bvec. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: remove the bi_phys_segments field in struct bioChristoph Hellwig
We only need the number of segments in the blk-mq submission path. Remove the field from struct bio, and return it from a variant of blk_queue_split instead of that it can passed as an argument to those functions that need the value. This also means we stop recounting segments except for cloning and partial segments. To keep the number of arguments in this how path down remove pointless struct request_queue arguments from any of the functions that had it and grew a nr_segs argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: remove blk_init_request_from_bioChristoph Hellwig
lightnvm should have never used this function, as it is sending passthrough requests, so switch it to blk_rq_append_bio like all the other passthrough request users. Inline blk_init_request_from_bio into the only remaining caller. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com> Reviewed-by: Javier González <javier@javigon.com> Reviewed-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: initialize the write priority in blk_rq_bio_prepChristoph Hellwig
The priority field also makes sense for passthrough requests, so initialize it in blk_rq_bio_prep. Reviewed-by: Minwoo Im <minwoo.im.dev@gmail.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20blk-iolatency: only account submitted biosDennis Zhou
As is, iolatency recognizes done_bio and cleanup as ending paths. If a request is marked REQ_NOWAIT and fails to get a request, the bio is cleaned up via rq_qos_cleanup() and ended in bio_wouldblock_error(). This results in underflowing the inflight counter. Fix this by only accounting bios that were actually submitted. Signed-off-by: Dennis Zhou <dennis@kernel.org> Cc: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20blk-core: Remove blk_end_request*() declarationsPavel Begunkov
Commit a1ce35fa49852db60fc6e268 ("block: remove dead elevator code") deleted blk_end_request() and friends, but some declaration are still left. Purge them. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: code cleanup queue_poll_stat_show()Chaitanya Kulkarni
This is a pure code cleanup patch and doesn't change any functionality. Having multiple coding styles in the code creates confusion when someone tries to add a new code. Make queue_poll_stat_show() consistent by adding spaces around binary operators with the rest of the code. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: use right format specifier for opChaitanya Kulkarni
In function __blk_mq_debugfs_rq_show variable op has unsigned int type. Since op can never be negative use %u format specifier to match the variable type. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: get rid of redundant elseChaitanya Kulkarni
This is a pure code cleanup patch and doesn't change any functionality. This removes the redundant else in the code which is not needed since we are returning from function anyway. Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-17block: use req_op() to maintain consistencyChaitanya Kulkarni
This is a pure code cleanup patch and doesn't change any functionality. In block layer to identify the request operation req_op() macro is used, so change the open coding the req_op() in the blk-mq-debugfs.c. Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-17block: fix page leak when merging to same pageChristoph Hellwig
When multiple iovecs reference the same page, each get_user_page call will add a reference to the page. But once we've created the bio that information gets lost and only a single reference will be dropped after I/O completion. Use the same_page information returned from __bio_try_merge_page to drop additional references to pages that were already present in the bio. Based on a patch from Ming Lei. Link: https://lkml.org/lkml/2019/4/23/64 Fixes: 576ed913 ("block: use bio_add_page in bio_iov_iter_get_pages") Reported-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-17block: return from __bio_try_merge_page if merging occured in the same pageChristoph Hellwig
We currently have an input same_page parameter to __bio_try_merge_page to prohibit merging in the same page. The rationale for that is that some callers need to account for every page added to a bio. Instead of letting these callers call twice into the merge code to account for the new vs existing page cases, just turn the paramter into an output one that returns if a merge in the same page occured and let them act accordingly. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15blkcg: blkcg_activate_policy() should initialize ancestors firstTejun Heo
When blkcg_activate_policy() is creating blkg_policy_data for existing blkgs, it did in the wrong order - descendants first. Fix it. None of the existing controllers seem affected by this. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15blkcg: perpcu_ref init/exit should be done from blkg_alloc/free()Tejun Heo
blkg alloc is performed as a separate step from the rest of blkg creation so that GFP_KERNEL allocations can be used when creating blkgs from configuration file writes because otherwise user actions may fail due to failures of opportunistic GFP_NOWAIT allocations. While making blkgs use percpu_ref, 7fcf2b033b84 ("blkcg: change blkg reference counting to use percpu_ref") incorrectly added unconditional opportunistic percpu_ref_init() to blkg_create() breaking this guarantee. This patch moves percpu_ref_init() to blkg_alloc() so makes it use @gfp_mask that blkg_alloc() is called with. Also, percpu_ref_exit() is moved to blkg_free() for consistency. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 7fcf2b033b84 ("blkcg: change blkg reference counting to use percpu_ref") Cc: Dennis Zhou <dennis@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15blkcg: update blkcg_print_stat() to handle larger outputsTejun Heo
Depending on the number of devices, blkcg stats can go over the default seqfile buf size. seqfile normally retries with a larger buffer but since the ->pd_stat() addition, blkcg_print_stat() doesn't tell seqfile that overflow has happened and the output gets printed truncated. Fix it by calling seq_commit() w/ -1 on possible overflows. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 903d23f0a354 ("blk-cgroup: allow controllers to output their own stats") Cc: stable@vger.kernel.org # v4.19+ Cc: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15blk-iolatency: clear use_delay when io.latency is set to zeroTejun Heo
If use_delay was non-zero when the latency target of a cgroup was set to zero, it will stay stuck until io.latency is enabled on the cgroup again. This keeps readahead disabled for the cgroup impacting performance negatively. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Josef Bacik <jbacik@fb.com> Fixes: d70675121546 ("block: introduce blk-iolatency io controller") Cc: stable@vger.kernel.org # v4.19+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15block: bio: Use struct_size() in kmalloc()Gustavo A. R. Silva
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct bio_map_data { ... struct iovec iov[]; }; instance = kmalloc(sizeof(sizeof(struct bio_map_data) + sizeof(struct iovec) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, iov, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15block: genhd: Use struct_size() helperGustavo A. R. Silva
Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes, in particular in the context in which this code is being used. So, replace the following form: sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]) with: struct_size(new_ptbl, part, target) Also, notice that variable size is unnecessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15blk-mq/debugfs: Fix improper print qualifierPavel Begunkov
struct blk_rq_stat::mean is a u64 value, so use %llu Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-14docs: cgroup-v1: convert docs to ReST and rename to *.rstMauro Carvalho Chehab
Convert the cgroup-v1 files to ReST format, in order to allow a later addition to the admin-guide. The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2019-06-13blk-mq: remove WARN_ON(!q->elevator) from blk_mq_sched_free_requestsMing Lei
blk_mq_sched_free_requests() may be called in failure path in which q->elevator may not be setup yet, so remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests for avoiding the false positive. This function is actually safe to call in case of !q->elevator because hctx->sched_tags is checked. Cc: Bart Van Assche <bvanassche@acm.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Yi Zhang <yi.zhang@redhat.com> Fixes: c3e2219216c9 ("block: free sched's request pool in blk_cleanup_queue") Reported-by: syzbot+b9d0d56867048c7bcfde@syzkaller.appspotmail.com Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-13blk-mq: no need to check return value of debugfs_create functionsGreg Kroah-Hartman
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. When all of these checks are cleaned up, lots of the functions used in the blk-mq-debugfs code can now return void, as no need to check the return value of them either. Overall, this ends up cleaning up the code and making it smaller, always a nice win. Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-13block: force select mq-deadline for zoned block devicesDamien Le Moal
In most use cases of zoned block devices (aka SMR disks), the mq-deadline scheduler is mandatory as it implements sequential write command processing guarantees with zone write locking. So make sure that this scheduler is always enabled if CONFIG_BLK_DEV_ZONED is selected. Tested-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-10cgroup/bfq: revert bfq.weight symlink changeJens Axboe
There's some discussion on how to do this the best, and Tejun prefers that BFQ just create the file itself instead of having cgroups support a symlink feature. Hence revert commit 54b7b868e826 and 19e9da9e86c4 for 5.2, and this can be done properly for 5.3. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-07block, bfq: add weight symlink to the bfq.weight cgroup parameterAngelo Ruocco
Many userspace tools and services use the proportional-share policy of the blkio/io cgroups controller. The CFQ I/O scheduler implemented this policy for the legacy block layer. To modify the weight of a group in case CFQ was in charge, the 'weight' parameter of the group must be modified. On the other hand, the BFQ I/O scheduler implements the same policy in blk-mq, but, with BFQ, the parameter to modify has a different name: bfq.weight (forced choice until legacy block was present, because two different policies cannot share a common parameter in cgroups). Due to CFQ legacy, most if not all userspace configurations still use the parameter 'weight', and for the moment do not seem likely to be changed. But, when CFQ went away with legacy block, such a parameter ceased to exist. So, a simple workaround has been proposed [1] to make all configurations work: add a symlink, named weight, to bfq.weight. This commit adds such a symlink. [1] https://lkml.org/lkml/2019/4/8/555 Suggested-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Angelo Ruocco <angeloruocco90@gmail.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-06block: free sched's request pool in blk_cleanup_queueMing Lei
In theory, IO scheduler belongs to request queue, and the request pool of sched tags belongs to the request queue too. However, the current tags allocation interfaces are re-used for both driver tags and sched tags, and driver tags is definitely host wide, and doesn't belong to any request queue, same with its request pool. So we need tagset instance for freeing request of sched tags. Meantime, blk_mq_free_tag_set() often follows blk_cleanup_queue() in case of non-BLK_MQ_F_TAG_SHARED, this way requires that request pool of sched tags to be freed before calling blk_mq_free_tag_set(). Commit 47cdee29ef9d94e ("block: move blk_exit_queue into __blk_release_queue") moves blk_exit_queue into __blk_release_queue for simplying the fast path in generic_make_request(), then causes oops during freeing requests of sched tags in __blk_release_queue(). Fix the above issue by move freeing request pool of sched tags into blk_cleanup_queue(), this way is safe becasue queue has been frozen and no any in-queue requests at that time. Freeing sched tags has to be kept in queue's release handler becasue there might be un-completed dispatch activity which might refer to sched tags. Cc: Bart Van Assche <bvanassche@acm.org> Cc: Christoph Hellwig <hch@lst.de> Fixes: 47cdee29ef9d94e485eb08f962c74943023a5271 ("block: move blk_exit_queue into __blk_release_queue") Tested-by: Yi Zhang <yi.zhang@redhat.com> Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-05block: Drop unlikely before IS_ERR(_OR_NULL)Kefeng Wang
IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag, so no need to do that again from its callers. Drop it. Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31block: print offending values when cloned rq limits are exceededJohn Pittman
While troubleshooting issues where cloned request limits have been exceeded, it is often beneficial to know the actual values that have been breached. Print these values, assisting in ease of identification of root cause of the breach. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: John Pittman <jpittman@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31blk-mq: Document the blk_mq_hw_queue_to_node() argumentsBart Van Assche
Document the meaning of the blk_mq_hw_queue_to_node() arguments. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31blk-mq: Fix spelling in a source code commentBart Van Assche
Change one occurrence of 'performace' into 'performance'. Cc: Max Gurtovoy <maxg@mellanox.com> Fixes: fe631457ff3e ("blk-mq: map all HWQ also in hyperthreaded system") # v4.13. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31block: Fix bsg_setup_queue() kernel-doc headerBart Van Assche
Document all bsg_setup_queue() arguments as required. Fixes: aae3b069d5ce ("bsg: pass in desired timeout handler") # v5.0. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31block: Fix rq_qos_wait() kernel-doc headerBart Van Assche
Add documentation for the @rqw argument and change " - " into ": ". Fixes: 84f603246db9 ("block: add rq_qos_wait to rq_qos") # v5.0-rc1~52^2~140. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31block: Fix blk_mq_*_map_queues() kernel-doc headersBart Van Assche
This patch avoids that the kernel-doc script complains about these function headers when building with W=1. Cc: Hannes Reinecke <hare@suse.com> Cc: Keith Busch <keith.busch@intel.com> Fixes: ed76e329d74a ("blk-mq: abstract out queue map") # v5.0. Fixes: e42b3867de4b ("blk-mq-rdma: pass in queue map to blk_mq_rdma_map_queues") # v5.0. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31block: Fix throtl_pending_timer_fn() kernel-doc headerBart Van Assche
Commit e99e88a9d2b0 renamed a function argument without updating the corresponding kernel-doc header. Update the kernel-doc header. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Reviewed-by: Kees Cook <keescook@chromium.org> Fixes: e99e88a9d2b0 ("treewide: setup_timer() -> timer_setup()") # v4.15. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31block: Convert blk_invalidate_devt() header into a non-kernel-doc headerBart Van Assche
This patch avoids that the kernel-doc tool warns about this function header when building with W=1. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-31block/partitions/ldm: Convert a kernel-doc header into a non-kernel-doc headerBart Van Assche
This patch avoids that the kernel-doc tool warns about this function header when building with W=1. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-29blk-mq: Fix memory leak in error handlingJes Sorensen
If blk_mq_init_allocated_queue() fails, make sure to free the poll stat callback struct allocated. Signed-off-by: Jes Sorensen <jsorensen@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-29block: don't protect generic_make_request_checks with blk_queue_enterMing Lei
Now a063057d7c73 ("block: Fix a race between request queue removal and the block cgroup controller") has been reverted, and blkcg_exit_queue() won't be called in blk_cleanup_queue() any more. So don't need to protect generic_make_request_checks() with blk_queue_enter(), then the total mess can be cleaned. 37f9579f4c31 ("blk-mq: Avoid that submitting a bio concurrently with device removal triggers a crash") is reverted. Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-29block: move blk_exit_queue into __blk_release_queueMing Lei
Commit 498f6650aec8 ("block: Fix a race between the cgroup code and request queue initialization") moves what blk_exit_queue does into blk_cleanup_queue() for fixing issue caused by changing back queue lock. However, after legacy request IO path is killed, driver queue lock won't be used at all, and there isn't story for changing back queue lock. Then the issue addressed by Commit 498f6650aec8 doesn't exist any more. So move move blk_exit_queue into __blk_release_queue. This patch basically reverts the following two commits: 498f6650aec8 block: Fix a race between the cgroup code and request queue initialization 24ecc3585348 block: Ensure that a request queue is dissociated from the cgroup controller Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23blk-mq: fix hang caused by freeze/unfreeze sequenceBob Liu
The following is a description of a hang in blk_mq_freeze_queue_wait(). The hang happens on attempt to freeze a queue while another task does queue unfreeze. The root cause is an incorrect sequence of percpu_ref_resurrect() and percpu_ref_kill() and as a result those two can be swapped: CPU#0 CPU#1 ---------------- ----------------- q1 = blk_mq_init_queue(shared_tags) q2 = blk_mq_init_queue(shared_tags): blk_mq_add_queue_tag_set(shared_tags): blk_mq_update_tag_set_depth(shared_tags): list_for_each_entry() blk_mq_freeze_queue(q1) > percpu_ref_kill() > blk_mq_freeze_queue_wait() blk_cleanup_queue(q1) blk_mq_freeze_queue(q1) > percpu_ref_kill() ^^^^^^ freeze_depth can't guarantee the order blk_mq_unfreeze_queue() > percpu_ref_resurrect() > blk_mq_freeze_queue_wait() ^^^^^^ Hang here!!!! This wrong sequence raises kernel warning: percpu_ref_kill_and_confirm called more than once on blk_queue_usage_counter_release! WARNING: CPU: 0 PID: 11854 at lib/percpu-refcount.c:336 percpu_ref_kill_and_confirm+0x99/0xb0 But the most unpleasant effect is a hang of a blk_mq_freeze_queue_wait(), which waits for a zero of a q_usage_counter, which never happens because percpu-ref was reinited (instead of being killed) and stays in PERCPU state forever. How to reproduce: - "insmod null_blk.ko shared_tags=1 nr_devices=0 queue_mode=2" - cpu0: python Script.py 0; taskset the corresponding process running on cpu0 - cpu1: python Script.py 1; taskset the corresponding process running on cpu1 Script.py: ------ #!/usr/bin/python3 import os import sys while True: on = "echo 1 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] off = "echo 0 > /sys/kernel/config/nullb/%s/power" % sys.argv[1] os.system(on) os.system(off) ------ This bug was first reported and fixed by Roman, previous discussion: [1] Message id: 1443287365-4244-7-git-send-email-akinobu.mita@gmail.com [2] Message id: 1443563240-29306-6-git-send-email-tj@kernel.org [3] https://patchwork.kernel.org/patch/9268199/ Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23block: remove the bi_seg_{front,back}_size fields in struct bioChristoph Hellwig
At this point these fields aren't used for anything, so we can remove them. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23block: remove the segment size check in bio_will_gapChristoph Hellwig
We fundamentally do not have a maximum segement size for devices with a virt boundary. So don't bother checking it, especially given that the existing checks didn't properly work to start with as we never fully update the front/back segment size and miss the bi_seg_front_size that wuld have been required for some cases. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23block: force an unlimited segment size on queues with a virt boundaryChristoph Hellwig
We currently fail to update the front/back segment size in the bio when deciding to allow an otherwise gappy segement to a device with a virt boundary. The reason why this did not cause problems is that devices with a virt boundary fundamentally don't use segments as we know it and thus don't care. Make that assumption formal by forcing an unlimited segement size in this case. Fixes: f6970f83ef79 ("block: don't check if adjacent bvecs in one bio can be mergeable") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-23block: don't decrement nr_phys_segments for physically contigous segmentsChristoph Hellwig
Currently ll_merge_requests_fn, unlike all other merge functions, reduces nr_phys_segments by one if the last segment of the previous, and the first segment of the next segement are contigous. While this seems like a nice solution to avoid building smaller than possible requests it causes a mismatch between the segments actually present in the request and those iterated over by the bvec iterators, including __rq_for_each_bio. This can for example mistrigger the single segment optimization in the nvme-pci driver, and might lead to mismatching nr_phys_segments number when recalculating the number of request when inserting a cloned request. We could possibly work around this by making the bvec iterators take the front and back segment size into account, but that would require moving them from the bio to the bio_iter and spreading this mess over all users of bvecs. Or we could simply remove this optimization under the assumption that most users already build good enough bvecs, and that the bio merge patch never cared about this optimization either. The latter is what this patch does. dff824b2aadb ("nvme-pci: optimize mapping of small single segment requests"). Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-16Merge tag 'for-5.2/block-post-20190516' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull more block updates from Jens Axboe: "This is mainly some late lightnvm changes that came in just before the merge window, as well as fixes that have been queued up since the initial pull request was frozen. This contains: - lightnvm changes, fixing race conditions, improving memory utilization, and improving pblk compatability (Chansol, Igor, Marcin) - NVMe pull request with minor fixes all over the map (via Christoph) - remove redundant error print in sata_rcar (Geert) - struct_size() cleanup (Jackie) - dasd CONFIG_LBADF warning fix (Ming) - brd cond_resched() improvement (Mikulas)" * tag 'for-5.2/block-post-20190516' of git://git.kernel.dk/linux-block: (41 commits) block/bio-integrity: use struct_size() in kmalloc() nvme: validate cntlid during controller initialisation nvme: change locking for the per-subsystem controller list nvme: trace all async notice events nvme: fix typos in nvme status code values nvme-fabrics: remove unused argument nvme-multipath: avoid crash on invalid subsystem cntlid enumeration nvme-fc: use separate work queue to avoid warning nvme-rdma: remove redundant reference between ib_device and tagset nvme-pci: mark expected switch fall-through nvme-pci: add known admin effects to augument admin effects log page nvme-pci: init shadow doorbell after each reset brd: add cond_resched to brd_free_pages sata_rcar: Remove ata_host_alloc() error printing s390/dasd: fix build warning in dasd_eckd_build_cp_raw lightnvm: pblk: use nvm_rq_to_ppa_list() lightnvm: pblk: simplify partial read path lightnvm: do not remove instance under global lock lightnvm: track inflight target creations lightnvm: pblk: recover only written metadata ...
2019-05-16block/bio-integrity: use struct_size() in kmalloc()Jackie Liu
Use the new struct_size() helper to keep code simple. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-07Merge tag 'for-5.2/block-20190507' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block updates from Jens Axboe: "Nothing major in this series, just fixes and improvements all over the map. This contains: - Series of fixes for sed-opal (David, Jonas) - Fixes and performance tweaks for BFQ (via Paolo) - Set of fixes for bcache (via Coly) - Set of fixes for md (via Song) - Enabling multi-page for passthrough requests (Ming) - Queue release fix series (Ming) - Device notification improvements (Martin) - Propagate underlying device rotational status in loop (Holger) - Removal of mtip32xx trim support, which has been disabled for years (Christoph) - Improvement and cleanup of nvme command handling (Christoph) - Add block SPDX tags (Christoph) - Cleanup/hardening of bio/bvec iteration (Christoph) - A few NVMe pull requests (Christoph) - Removal of CONFIG_LBDAF (Christoph) - Various little fixes here and there" * tag 'for-5.2/block-20190507' of git://git.kernel.dk/linux-block: (164 commits) block: fix mismerge in bvec_advance block: don't drain in-progress dispatch in blk_cleanup_queue() blk-mq: move cancel of hctx->run_work into blk_mq_hw_sysfs_release blk-mq: always free hctx after request queue is freed blk-mq: split blk_mq_alloc_and_init_hctx into two parts blk-mq: free hw queue's resource in hctx's release handler blk-mq: move cancel of requeue_work into blk_mq_release blk-mq: grab .q_usage_counter when queuing request from plug code path block: fix function name in comment nvmet: protect discovery change log event list iteration nvme: mark nvme_core_init and nvme_core_exit static nvme: move command size checks to the core nvme-fabrics: check more command sizes nvme-pci: check more command sizes nvme-pci: remove an unneeded variable initialization nvme-pci: unquiesce admin queue on shutdown nvme-pci: shutdown on timeout during deletion nvme-pci: fix psdt field for single segment sgls nvme-multipath: don't print ANA group state by default nvme-multipath: split bios with the ns_head bio_set before submitting ...