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2018-01-05block: introduce zoned block devices zone write lockingChristoph Hellwig1-0/+42
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>
2017-08-23block: replace bi_bdev with a gendisk pointer and partitions indexChristoph Hellwig1-2/+2
This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-01-12block: Rename blk_queue_zone_size and bdev_zone_sizeDamien Le Moal1-2/+2
All block device data fields and functions returning a number of 512B sectors are by convention named xxx_sectors while names in the form xxx_size are generally used for a number of bytes. The blk_queue_zone_size and bdev_zone_size functions were not following this convention so rename them. No functional change is introduced by this patch. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Collapsed the two patches, they were nonsensically split and broke bisection. Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-25block: zoned: fix harmless maybe-uninitialized warningArnd Bergmann1-4/+2
The blkdev_report_zones produces a harmless warning when -Wmaybe-uninitialized is set, after gcc gets a little confused about the multiple 'goto' here: block/blk-zoned.c: In function 'blkdev_report_zones': block/blk-zoned.c:188:13: error: 'nz' may be used uninitialized in this function [-Werror=maybe-uninitialized] Moving the assignment to nr_zones makes this a little simpler while also avoiding the warning reliably. I'm removing the extraneous initialization of 'int ret' in the same patch, as that is semi-related and could cause an uninitialized use of that variable to not produce a warning. Fixes: 6a0cb1bc106f ("block: Implement support for zoned block devices") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18blk-zoned: implement ioctlsShaun Tancheff1-0/+93
Adds the new BLKREPORTZONE and BLKRESETZONE ioctls for respectively obtaining the zone configuration of a zoned block device and resetting the write pointer of sequential zones of a zoned block device. The BLKREPORTZONE ioctl maps directly to a single call of the function blkdev_report_zones. The zone information result is passed as an array of struct blk_zone identical to the structure used internally for processing the REQ_OP_ZONE_REPORT operation. The BLKRESETZONE ioctl maps to a single call of the blkdev_reset_zones function. Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-18block: Implement support for zoned block devicesHannes Reinecke1-0/+257
Implement zoned block device zone information reporting and reset. Zone information are reported as struct blk_zone. This implementation does not differentiate between host-aware and host-managed device models and is valid for both. Two functions are provided: blkdev_report_zones for discovering the zone configuration of a zoned block device, and blkdev_reset_zones for resetting the write pointer of sequential zones. The helper function blk_queue_zone_size and bdev_zone_size are also provided for, as the name suggest, obtaining the zone size (in 512B sectors) of the zones of the device. Signed-off-by: Hannes Reinecke <hare@suse.de> [Damien: * Removed the zone cache * Implement report zones operation based on earlier proposal by Shaun Tancheff <shaun.tancheff@seagate.com>] Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com> Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com> Signed-off-by: Jens Axboe <axboe@fb.com>