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2020-10-05block: add a bdget_part helperChristoph Hellwig1-1/+1
All remaining callers of bdget() outside of fs/block_dev.c want to get a reference to the struct block_device for a given struct hd_struct. Add a helper just for that and then mark bdget static. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-25block: use bd_partno in bdevnameChristoph Hellwig1-1/+1
No need to go through the hd_struct to find the partition number. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-23block: cleanup partition scanning in register_diskChristoph Hellwig1-19/+14
Use blkdev_get_by_dev instead of open coding it using bdget_disk + blkdev_get, and split the code to read the partition table into a separate helper to make it a little more obvious. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-23block: move the NEED_PART_SCAN flag to struct gendiskChristoph Hellwig1-2/+2
We can only scan for partitions on the whole disk, so move the flag from struct block_device to struct gendisk. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-10block: add a bdev_check_media_change helperChristoph Hellwig1-1/+28
Like check_disk_changed, except that it does not call ->revalidate_disk but leaves that to the caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-02block: use revalidate_disk_size in set_capacity_revalidate_and_notifyChristoph Hellwig1-4/+3
Only virtio_blk and xen-blkfront set the revalidate argument to true, and both do not implement the ->revalidate_disk method. So switch to the helper that just updates the size instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-02block: rename bd_invalidatedChristoph Hellwig1-1/+1
Replace bd_invalidate with a new BDEV_NEED_PART_SCAN flag in a bd_flags variable to better describe the condition. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-01block: remove the unused q argument to part_in_flight and part_in_flight_rwChristoph Hellwig1-7/+5
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-01block: remove the disk argument to delete_partitionChristoph Hellwig1-1/+1
We can trivially derive the gendisk from the hd_struct. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-01block: cleanup __alloc_disk_nodeChristoph Hellwig1-35/+38
Use early returns and goto-based unwinding to simplify the flow a bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-31block: genhd: delete duplicated wordsRandy Dunlap1-3/+3
Drop the repeated word "to" in multiple places. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-17blk-cgroup: show global disk stats in root cgroup io.statBoris Burkov1-3/+1
In order to improve consistency and usability in cgroup stat accounting, we would like to support the root cgroup's io.stat. Since the root cgroup has processes doing io even if the system has no explicitly created cgroups, we need to be careful to avoid overhead in that case. For that reason, the rstat algorithms don't handle the root cgroup, so just turning the file on wouldn't give correct statistics. To get around this, we simulate flushing the iostat struct by filling it out directly from global disk stats. The result is a root cgroup io.stat file consistent with both /proc/diskstats and io.stat. Note that in order to collect the disk stats, we needed to iterate over devices. To facilitate that, we had to change the linkage of a disk_type to external so that it can be used from blk-cgroup.c to iterate over disks. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Boris Burkov <boris@bur.io> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-08md: switch to ->check_events for media change notificationsChristoph Hellwig1-7/+1
md is the last driver using the legacy media_changed method. Switch it over to (not so) new ->clear_events approach, which also removes the need for the ->revalidate_disk method. Signed-off-by: Christoph Hellwig <hch@lst.de> [axboe: remove unused 'bdops' variable in disk_clear_events()] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-24block: revert back to synchronous request_queue removalLuis Chamberlain1-0/+17
Commit dc9edc44de6c ("block: Fix a blk_exit_rl() regression") merged on v4.12 moved the work behind blk_release_queue() into a workqueue after a splat floated around which indicated some work on blk_release_queue() could sleep in blk_exit_rl(). This splat would be possible when a driver called blk_put_queue() or blk_cleanup_queue() (which calls blk_put_queue() as its final call) from an atomic context. blk_put_queue() decrements the refcount for the request_queue kobject, and upon reaching 0 blk_release_queue() is called. Although blk_exit_rl() is now removed through commit db6d99523560 ("block: remove request_list code") on v5.0, we reserve the right to be able to sleep within blk_release_queue() context. The last reference for the request_queue must not be called from atomic context. *When* the last reference to the request_queue reaches 0 varies, and so let's take the opportunity to document when that is expected to happen and also document the context of the related calls as best as possible so we can avoid future issues, and with the hopes that the synchronous request_queue removal sticks. We revert back to synchronous request_queue removal because asynchronous removal creates a regression with expected userspace interaction with several drivers. An example is when removing the loopback driver, one uses ioctls from userspace to do so, but upon return and if successful, one expects the device to be removed. Likewise if one races to add another device the new one may not be added as it is still being removed. This was expected behavior before and it now fails as the device is still present and busy still. Moving to asynchronous request_queue removal could have broken many scripts which relied on the removal to have been completed if there was no error. Document this expectation as well so that this doesn't regress userspace again. Using asynchronous request_queue removal however has helped us find other bugs. In the future we can test what could break with this arrangement by enabling CONFIG_DEBUG_KOBJECT_RELEASE. While at it, update the docs with the context expectations for the request_queue / gendisk refcount decrement, and make these expectations explicit by using might_sleep(). Fixes: dc9edc44de6c ("block: Fix a blk_exit_rl() regression") Suggested-by: Nicolai Stange <nstange@suse.de> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Omar Sandoval <osandov@fb.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: yu kuai <yukuai3@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-24block: clarify context for refcount increment helpersLuis Chamberlain1-0/+6
Let us clarify the context under which the helpers to increment the refcount for the gendisk and request_queue can be called under. We make this explicit on the places where we may sleep with might_sleep(). We don't address the decrement context yet, as that needs some extra work and fixes, but will be addressed in the next patch. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-24block: add docs for gendisk / request_queue refcount helpersLuis Chamberlain1-1/+49
This adds documentation for the gendisk / request_queue refcount helpers. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-27block: remove rcu_read_lock() from part_stat_lock()Konstantin Khlebnikov1-3/+8
The RCU lock is required only in disk_map_sector_rcu() to lookup the partition. After that request holds reference to related hd_struct. Replace get_cpu() with preempt_disable() - returned cpu index is unused. [hch: rebased] Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-27block: always use a percpu variable for disk statsChristoph Hellwig1-9/+3
percpu variables have a perfectly fine working stub implementation for UP kernels, so use that. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-19block: merge part_{inc,dev}_in_flight into their only callersChristoph Hellwig1-20/+0
part_inc_in_flight and part_dec_in_flight only have one caller each, and those callers are purely for bio based drivers. Merge each function into the only caller, and remove the superflous blk-mq checks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-19block: move the blk-mq calls out of part_in_flight{,_rw}Christoph Hellwig1-14/+14
Don't bother to call part_in_flight / part_in_flight_rw on blk-mq devices, just call the blk-mq versions directly. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-12block: don't hold part0's refcount in IO pathMing Lei1-2/+2
gendisk can't be gone when there is IO activity, so not hold part0's refcount in IO path. Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@infradead.org> Cc: Yufen Yu <yuyufen@huawei.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-12block: only define 'nr_sects_seq' in hd_part for 32bit SMPMing Lei1-1/+1
The seqcount of 'nr_sects_seq' is only needed in case of 32bit SMP, so define it just for 32bit SMP. Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@infradead.org> Cc: Yufen Yu <yuyufen@huawei.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-12block: fix use-after-free on cached last_lookup partitionMing Lei1-3/+12
delete_partition() clears the cached last_lookup partition. However the .last_lookup cache may be overwritten by one IO path after it is cleared from delete_partition(). Then another IO path may use the cached deleting partition after hd_struct_free() is called, then use-after-free is triggered on the cached partition. Fixes the issue by the following approach: 1) always get the partition's refcount via hd_struct_try_get() before setting .last_lookup 2) move clearing .last_lookup from delete_partition() to hd_struct_free() which is the release handle of the partition's percpu-refcount, so that no IO path can cache deleteing partition via .last_lookup. It is one candidate approach of Yufen's patch[1] which adds overhead in fast path by indirect lookup which may introduce one extra cacheline in IO path. Also this patch relies on percpu-refcount's protection, and it is easier to understand and verify. [1] https://lore.kernel.org/linux-block/20200109013551.GB9655@ming.t460p/T/#t Reported-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@infradead.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-09bdi: remove bdi_register_ownerChristoph Hellwig1-3/+5
Split out a new bdi_set_owner helper to set the owner, and move the policy for creating the bdi name back into genhd.c, where it belongs. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-20block: fold bdev_unhash_inode into invalidate_partitionChristoph Hellwig1-2/+6
invalidate_partition and bdev_unhash_inode are always paired, and invalidate_partition already does an icache lookup for the block device inode. Piggy back on that to remove the inode from the hash. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-20block: mark invalidate_partition staticChristoph Hellwig1-14/+13
invalidate_partition is only used in genhd.c, so mark it static. Also drop the return value given that is is always ignored. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-20block: pass a hd_struct to delete_partitionChristoph Hellwig1-1/+1
All callers have the hd_struct at hand, so pass it instead of performing another lookup. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-30Merge tag 'for-5.7/block-2020-03-29' of git://git.kernel.dk/linux-blockLinus Torvalds1-27/+192
Pull block updates from Jens Axboe: - Online capacity resizing (Balbir) - Number of hardware queue change fixes (Bart) - null_blk fault injection addition (Bart) - Cleanup of queue allocation, unifying the node/no-node API (Christoph) - Cleanup of genhd, moving code to where it makes sense (Christoph) - Cleanup of the partition handling code (Christoph) - disk stat fixes/improvements (Konstantin) - BFQ improvements (Paolo) - Various fixes and improvements * tag 'for-5.7/block-2020-03-29' of git://git.kernel.dk/linux-block: (72 commits) block: return NULL in blk_alloc_queue() on error block: move bio_map_* to blk-map.c Revert "blkdev: check for valid request queue before issuing flush" block: simplify queue allocation bcache: pass the make_request methods to blk_queue_make_request null_blk: use blk_mq_init_queue_data block: add a blk_mq_init_queue_data helper block: move the ->devnode callback to struct block_device_operations block: move the part_stat* helpers from genhd.h to a new header block: move block layer internals out of include/linux/genhd.h block: move guard_bio_eod to bio.c block: unexport get_gendisk block: unexport disk_map_sector_rcu block: unexport disk_get_part block: mark part_in_flight and part_in_flight_rw static block: mark block_depr static block: factor out requeue handling from dispatch code block/diskstats: replace time_in_queue with sum of request times block/diskstats: accumulate all per-cpu counters in one pass block/diskstats: more accurate approximation of io_ticks for slow disks ...
2020-03-27block: move the ->devnode callback to struct block_device_operationsChristoph Hellwig1-2/+2
There really isn't any good reason to stash a method directly into struct gendisk. Move it together with the other block device operations. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25block: unexport get_gendiskChristoph Hellwig1-1/+0
get_gendisk is not used by any modular code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25block: unexport disk_map_sector_rcuChristoph Hellwig1-1/+0
disk_map_sector_rcu is not used by any modular code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25block: unexport disk_get_partChristoph Hellwig1-1/+0
disk_get_part is not used by any modular code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25block: mark part_in_flight and part_in_flight_rw staticChristoph Hellwig1-3/+4
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25block: mark block_depr staticChristoph Hellwig1-1/+1
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25block/diskstats: replace time_in_queue with sum of request timesKonstantin Khlebnikov1-3/+10
Column "time_in_queue" in diskstats is supposed to show total waiting time of all requests. I.e. value should be equal to the sum of times from other columns. But this is not true, because column "time_in_queue" is counted separately in jiffies rather than in nanoseconds as other times. This patch removes redundant counter for "time_in_queue" and shows total time of read, write, discard and flush requests. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-25block/diskstats: accumulate all per-cpu counters in one passKonstantin Khlebnikov1-32/+70
Reading /proc/diskstats iterates over all cpus for summing each field. It's faster to sum all fields in one pass. Hammering /proc/diskstats with fio shows 2x performance improvement: fio --name=test --numjobs=$JOBS --filename=/proc/diskstats \ --size=1k --bs=1k --fallocate=none --create_on_open=1 \ --time_based=1 --runtime=10 --invalidate=0 --group_report JOBS=1 JOBS=10 Before: 7k iops 64k iops After: 18k iops 120k iops Also this way code is more compact: add/remove: 1/0 grow/shrink: 0/2 up/down: 194/-1540 (-1346) Function old new delta part_stat_read_all - 194 +194 diskstats_show 1344 631 -713 part_stat_show 1219 392 -827 Total: Before=14966947, After=14965601, chg -0.01% Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-24block: move sysfs methods shared by disks and partitions to genhd.cChristoph Hellwig1-1/+79
Move the sysfs _show methods that are used both on the full disk and partition nodes to genhd.c instead of hiding them in the partitioning code. Also move the declaration for these methods to block/blk.h so that we don't expose them to drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-24block: move disk_name and related helpers out of partition-generic.cChristoph Hellwig1-0/+21
Thes functions aren't really related to partition support, so move them to a more suitable place. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-24block: remove the blk_lookup_devt exportChristoph Hellwig1-1/+0
This function is only used by init/do_mounts.c, which can't be modular. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-18block/genhd: Notify udev about capacity changeBalbir Singh1-0/+24
Allow block/genhd to notify user space (via udev) about disk size changes using a new helper set_capacity_revalidate_and_notify(), which is a wrapper on top of set_capacity(). set_capacity_revalidate_and_notify() will only notify via udev if the current capacity or the target capacity is not zero and iff the capacity changes. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Someswarudu Sangaraju <ssomesh@amazon.com> Signed-off-by: Balbir Singh <sblbir@amazon.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-12block: Fix partition support for host aware zoned block devicesShin'ichiro Kawasaki1-0/+36
Commit b72053072c0b ("block: allow partitions on host aware zone devices") introduced the helper function disk_has_partitions() to check if a given disk has valid partitions. However, since this function result directly depends on the disk partition table length rather than the actual existence of valid partitions in the table, it returns true even after all partitions are removed from the disk. For host aware zoned block devices, this results in zone management support to be kept disabled even after removing all partitions. Fix this by changing disk_has_partitions() to walk through the partition table entries and return true if and only if a valid non-zero size partition is found. Fixes: b72053072c0b ("block: allow partitions on host aware zone devices") Cc: stable@vger.kernel.org # 5.5 Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-11-21block: add iostat counters for flush requestsKonstantin Khlebnikov1-2/+6
Requests that triggers flushing volatile writeback cache to disk (barriers) have significant effect to overall performance. Block layer has sophisticated engine for combining several flush requests into one. But there is no statistics for actual flushes executed by disk. Requests which trigger flushes usually are barriers - zero-size writes. This patch adds two iostat counters into /sys/class/block/$dev/stat and /proc/diskstats - count of completed flush requests and their total time. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-05block: Delay default elevator initializationDamien Le Moal1-0/+9
When elevator_init_mq() is called from blk_mq_init_allocated_queue(), the only information known about the device is the number of hardware queues as the block device scan by the device driver is not completed yet for most drivers. The device type and elevator required features are not set yet, preventing to correctly select the default elevator most suitable for the device. This currently affects all multi-queue zoned block devices which default to the "none" elevator instead of the required "mq-deadline" elevator. These drives currently include host-managed SMR disks connected to a smartpqi HBA and null_blk block devices with zoned mode enabled. Upcoming NVMe Zoned Namespace devices will also be affected. Fix this by adding the boolean elevator_init argument to blk_mq_init_allocated_queue() to control the execution of elevator_init_mq(). Two cases exist: 1) elevator_init = false is used for calls to blk_mq_init_allocated_queue() within blk_mq_init_queue(). In this case, a call to elevator_init_mq() is added to __device_add_disk(), resulting in the delayed initialization of the queue elevator after the device driver finished probing the device information. This effectively allows elevator_init_mq() access to more information about the device. 2) elevator_init = true preserves the current behavior of initializing the elevator directly from blk_mq_init_allocated_queue(). This case is used for the special request based DM devices where the device gendisk is created before the queue initialization and device information (e.g. queue limits) is already known when the queue initialization is executed. Additionally, to make sure that the elevator initialization is never done while requests are in-flight (there should be none when the device driver calls device_add_disk()), freeze and quiesce the device request queue before calling blk_mq_init_sched() in elevator_init_mq(). Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-07-16block: fix sysfs module parameters directory path in commentAkinobu Mita1-1/+1
The runtime configurable module parameter files are located under /sys/module/MODULENAME/parameters, not /sys/module/MODULENAME. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-15block: genhd: Use struct_size() helperGustavo A. R. Silva1-3/+2
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>
2019-05-31block: Convert blk_invalidate_devt() header into a non-kernel-doc headerBart Van Assche1-2/+2
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>
2019-04-30block: add SPDX tags to block layer files missing licensing informationChristoph Hellwig1-0/+1
Various block layer files do not have any licensing information at all. Add SPDX tags for the default kernel GPLv2 license to those. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-22block: fix use-after-free on gendiskYufen Yu1-0/+19
commit 2da78092dda "block: Fix dev_t minor allocation lifetime" specifically moved blk_free_devt(dev->devt) call to part_release() to avoid reallocating device number before the device is fully shutdown. However, it can cause use-after-free on gendisk in get_gendisk(). We use md device as example to show the race scenes: Process1 Worker Process2 md_free blkdev_open del_gendisk add delete_partition_work_fn() to wq __blkdev_get get_gendisk put_disk disk_release kfree(disk) find part from ext_devt_idr get_disk_and_module(disk) cause use after free delete_partition_work_fn put_device(part) part_release remove part from ext_devt_idr Before <devt, hd_struct pointer> is removed from ext_devt_idr by delete_partition_work_fn(), we can find the devt and then access gendisk by hd_struct pointer. But, if we access the gendisk after it have been freed, it can cause in use-after-freeon gendisk in get_gendisk(). We fix this by adding a new helper blk_invalidate_devt() in delete_partition() and del_gendisk(). It replaces hd_struct pointer in idr with value 'NULL', and deletes the entry from idr in part_release() as we do now. Thanks to Jan Kara for providing the solution and more clear comments for the code. Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime") Cc: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-12block: check_events: don't bother with events if unsupportedMartin Wilck1-11/+16
Drivers now report to the block layer if they support media change events. If this is not the case, there's no need to allocate the event structure, and all event handling code can effectively be skipped. This simplifies code flow in particular for non-removable sd devices. This effectively reverts commit 75e3f3ee3c64 ("block: always allocate genhd->ev if check_events is implemented"). The sysfs files for the events are kept in place even if no events are supported, as user space may rely on them being present. The only difference is that an error code is now returned if the user tries to set poll_msecs. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin Wilck <mwilck@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-12block: disk_events: introduce event flagsMartin Wilck1-4/+9
Currently, an empty disk->events field tells the block layer not to forward media change events to user space. This was done in commit 7c88a168da80 ("block: don't propagate unlisted DISK_EVENTs to userland") in order to avoid events from "fringe" drivers to be forwarded to user space. By doing so, the block layer lost the information which events were supported by a particular block device, and most importantly, whether or not a given device supports media change events at all. Prepare for not interpreting the "events" field this way in the future any more. This is done by adding an additional field "event_flags" to struct gendisk, and two flag bits that can be set to have the device treated like one that had the "events" field set to a non-zero value before. This applies only to the sd and sr drivers, which are changed to set the new flags. The new flags are DISK_EVENT_FLAG_POLL to enforce polling of the device for synchronous events, and DISK_EVENT_FLAG_UEVENT to tell the blocklayer to generate udev events from kernel events. In order to add the event_flags field to struct gendisk, the events field is converted to an "unsigned short"; it doesn't need to hold values bigger than 2 anyway. This patch doesn't change behavior. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin Wilck <mwilck@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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