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path: root/block/blk-ia-ranges.c
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2022-11-30block: untangle request_queue refcounting from sysfsChristoph Hellwig1-1/+2
The kobject embedded into the request_queue is used for the queue directory in sysfs, but that is a child of the gendisks directory and is intimately tied to it. Move this kobject to the gendisk and use a refcount_t in the request_queue for the actual request_queue refcounting that is completely unrelated to the device model. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221114042637.1009333-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-06-29block: simplify disk_set_independent_access_rangesChristoph Hellwig1-41/+16
Lift setting disk->ia_ranges from disk_register_independent_access_ranges into disk_set_independent_access_ranges, and make the behavior the same for the registered vs non-registered queue cases. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Link: https://lore.kernel.org/r/20220629062013.1331068-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-06-29block: move ->ia_ranges from the request_queue to the gendiskChristoph Hellwig1-9/+9
Independent access ranges only matter for file system I/O and are only valid with a registered gendisk, so move them there. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Link: https://lore.kernel.org/r/20220629062013.1331068-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-06-19block: remove queue from struct blk_independent_access_rangeDamien Le Moal1-1/+0
The request queue pointer in struct blk_independent_access_range is unused. Remove it. Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Fixes: 41e46b3c2aa2 ("block: Fix potential deadlock in blk_ia_range_sysfs_show()") Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220603053529.76405-1-damien.lemoal@opensource.wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-06-02block: Fix potential deadlock in blk_ia_range_sysfs_show()Damien Le Moal1-6/+1
When being read, a sysfs attribute is already protected against removal with the kobject node active reference counter. As a result, in blk_ia_range_sysfs_show(), there is no need to take the queue sysfs lock when reading the value of a range attribute. Using the queue sysfs lock in this function creates a potential deadlock situation with the disk removal, something that a lockdep signals with a splat when the device is removed: [ 760.703551] Possible unsafe locking scenario: [ 760.703551] [ 760.703554] CPU0 CPU1 [ 760.703556] ---- ---- [ 760.703558] lock(&q->sysfs_lock); [ 760.703565] lock(kn->active#385); [ 760.703573] lock(&q->sysfs_lock); [ 760.703579] lock(kn->active#385); [ 760.703587] [ 760.703587] *** DEADLOCK *** Solve this by removing the mutex_lock()/mutex_unlock() calls from blk_ia_range_sysfs_show(). Fixes: a2247f19ee1c ("block: Add independent access ranges support") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Link: https://lore.kernel.org/r/20220603021905.1441419-1-damien.lemoal@opensource.wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-23block: fix memory leak in disk_register_independent_access_rangesMiaoqian Lin1-1/+1
kobject_init_and_add() takes reference even when it fails. According to the doc of kobject_init_and_add() If this function returns an error, kobject_put() must be called to properly clean up the memory associated with the object. Fix this issue by adding kobject_put(). Callback function blk_ia_ranges_sysfs_release() in kobject_put() can handle the pointer "iars" properly. Fixes: a2247f19ee1c ("block: Add independent access ranges support") Signed-off-by: Miaoqian Lin <linmq006@gmail.com> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Link: https://lore.kernel.org/r/20220120101025.22411-1-linmq006@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-11block: fix kerneldoc for disk_register_independent_access__ranges()Jens Axboe1-2/+2
The naming got changed as part of a revision of the patchset, but the kerneldoc apparently never got updated. Fix it. Reported-by: kernel test robot <lkp@intel.com> Fixes: a2247f19ee1c ("block: Add independent access ranges support") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-26block: Add independent access ranges supportDamien Le Moal1-0/+348
The Concurrent Positioning Ranges VPD page (for SCSI) and data log page (for ATA) contain parameters describing the set of contiguous LBAs that can be served independently by a single LUN multi-actuator hard-disk. Similarly, a logically defined block device composed of multiple disks can in some cases execute requests directed at different sector ranges in parallel. A dm-linear device aggregating 2 block devices together is an example. This patch implements support for exposing a block device independent access ranges to the user through sysfs to allow optimizing device accesses to increase performance. To describe the set of independent sector ranges of a device (actuators of a multi-actuator HDDs or table entries of a dm-linear device), The type struct blk_independent_access_ranges is introduced. This structure describes the sector ranges using an array of struct blk_independent_access_range structures. This range structure defines the start sector and number of sectors of the access range. The ranges in the array cannot overlap and must contain all sectors within the device capacity. The function disk_set_independent_access_ranges() allows a device driver to signal to the block layer that a device has multiple independent access ranges. In this case, a struct blk_independent_access_ranges is attached to the device request queue by the function disk_set_independent_access_ranges(). The function disk_alloc_independent_access_ranges() is provided for drivers to allocate this structure. struct blk_independent_access_ranges contains kobjects (struct kobject) to expose to the user through sysfs the set of independent access ranges supported by a device. When the device is initialized, sysfs registration of the ranges information is done from blk_register_queue() using the block layer internal function disk_register_independent_access_ranges(). If a driver calls disk_set_independent_access_ranges() for a registered queue, e.g. when a device is revalidated, disk_set_independent_access_ranges() will execute disk_register_independent_access_ranges() to update the sysfs attribute files. The sysfs file structure created starts from the independent_access_ranges sub-directory and contains the start sector and number of sectors of each range, with the information for each range grouped in numbered sub-directories. E.g. for a dual actuator HDD, the user sees: $ tree /sys/block/sdk/queue/independent_access_ranges/ /sys/block/sdk/queue/independent_access_ranges/ |-- 0 | |-- nr_sectors | `-- sector `-- 1 |-- nr_sectors `-- sector For a regular device with a single access range, the independent_access_ranges sysfs directory does not exist. Device revalidation may lead to changes to this structure and to the attribute values. When manipulated, the queue sysfs_lock and sysfs_dir_lock mutexes are held for atomicity, similarly to how the blk-mq and elevator sysfs queue sub-directories are protected. The code related to the management of independent access ranges is added in the new file block/blk-ia-ranges.c. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Keith Busch <kbusch@kernel.org> Link: https://lore.kernel.org/r/20211027022223.183838-2-damien.lemoal@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>