lwn.git/drivers/s390/block/dasd_genhd.c, branch docs-fixes

s390/dasd: Move device name formatting into separate function

2025-11-26T17:14:17+00:00

The device name formatting can be generalized and made more readable compared to the current state. SCSI already provides a generalized way to format many devices in the same naming scheme as DASD does, which was introduced with commit 3e1a7ff8a0a7 ("block: allow disk to have extended device number"). Use this much cleaner code from drivers/scsi/sd.c to handle the legacy naming scheme in DASD as a replacement for the current implementation. For easier error handling for the new function, move the gendisk free portion of dasd_gendisk_free() out into a new function dasd_gd_free(). Signed-off-by: Jan Höppner Reviewed-by: Stefan Haberland Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe

block: remove BLK_MQ_F_SHOULD_MERGE

2024-12-23T15:17:23+00:00

BLK_MQ_F_SHOULD_MERGE is set for all tag_sets except those that purely process passthrough commands (bsg-lib, ufs tmf, various nvme admin queues) and thus don't even check the flag. Remove it to simplify the driver interface. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241219060214.1928848-1-hch@lst.de Signed-off-by: Jens Axboe

s390/dasd: Remove DMA alignment

2024-08-12T16:31:08+00:00

This reverts commit bc792884b76f ("s390/dasd: Establish DMA alignment"). Quoting the original commit: linux-next commit bf8d08532bc1 ("iomap: add support for dma aligned direct-io") changes the alignment requirement to come from the block device rather than the block size, and the default alignment requirement is 512-byte boundaries. Since DASD I/O has page alignments for IDAW/TIDAW requests, let's override this value to restore the expected behavior. I mentioned TIDAW, but that was wrong. TIDAWs have no distinct alignment requirement (per p. 15-70 of POPS SA22-7832-13): Unless otherwise specified, TIDAWs may designate a block of main storage on any boundary and length up to 4K bytes, provided the specified block does not cross a 4 K-byte boundary. IDAWs do, but the original commit neglected that while ECKD DASD are typically formatted in 4096-byte blocks, they don't HAVE to be. Formatting an ECKD volume with smaller blocks is permitted (dasdfmt -b xxx), and the problematic commit enforces alignment properties to such a device that will result in errors, such as: [test@host ~]# lsdasd -l a367 | grep blksz blksz: 512 [test@host ~]# mkfs.xfs -f /dev/disk/by-path/ccw-0.0.a367-part1 meta-data=/dev/dasdc1 isize=512 agcount=4, agsize=230075 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=1, sparse=1, rmapbt=1 = reflink=1 bigtime=1 inobtcount=1 nrext64=1 data = bsize=4096 blocks=920299, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0, ftype=1 log =internal log bsize=4096 blocks=16384, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 error reading existing superblock: Invalid argument mkfs.xfs: pwrite failed: Invalid argument libxfs_bwrite: write failed on (unknown) bno 0x70565c/0x100, err=22 mkfs.xfs: Releasing dirty buffer to free list! found dirty buffer (bulk) on free list! mkfs.xfs: pwrite failed: Invalid argument ...snipped... The original commit omitted the FBA discipline for just this reason, but the formatted block size of the other disciplines was overlooked. The solution to all of this is to revert to the original behavior, such that the block size can be respected. There were two commits [1] that moved this code in the interim, so a straight git-revert is not possible, but the change is straightforward. But what of the original problem? That was manifested with a direct-io QEMU guest, where QEMU itself was changed a month or two later with commit 25474d90aa ("block: use the request length for iov alignment") such that the blamed kernel commit is unnecessary. [1] commit 0127a47f58c6 ("dasd: move queue setup to common code") commit fde07a4d74e3 ("dasd: use the atomic queue limits API") Fixes: bc792884b76f ("s390/dasd: Establish DMA alignment") Reviewed-by: Stefan Haberland Signed-off-by: Eric Farman Signed-off-by: Stefan Haberland Link: https://lore.kernel.org/r/20240812125733.126431-2-sth@linux.ibm.com Signed-off-by: Jens Axboe

block: move the nonrot flag to queue_limits

2024-06-19T13:58:28+00:00

Move the nonrot flag into the queue_limits feature field so that it can be set atomically with the queue frozen. Use the chance to switch to defaulting to non-rotational and require the driver to opt into rotational, which matches the polarity of the sysfs interface. For the z2ram, ps3vram, 2x memstick, ubiblock and dcssblk the new rotational flag is not set as they clearly are not rotational despite this being a behavior change. There are some other drivers that unconditionally set the rotational flag to keep the existing behavior as they arguably can be used on rotational devices even if that is probably not their main use today (e.g. virtio_blk and drbd). The flag is automatically inherited in blk_stack_limits matching the existing behavior in dm and md. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20240617060532.127975-15-hch@lst.de Signed-off-by: Jens Axboe

Merge tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux

2024-03-11T18:43:44+00:00

Pull block updates from Jens Axboe: - MD pull requests via Song: - Cleanup redundant checks (Yu Kuai) - Remove deprecated headers (Marc Zyngier, Song Liu) - Concurrency fixes (Li Lingfeng) - Memory leak fix (Li Nan) - Refactor raid1 read_balance (Yu Kuai, Paul Luse) - Clean up and fix for md_ioctl (Li Nan) - Other small fixes (Gui-Dong Han, Heming Zhao) - MD atomic limits (Christoph) - NVMe pull request via Keith: - RDMA target enhancements (Max) - Fabrics fixes (Max, Guixin, Hannes) - Atomic queue_limits usage (Christoph) - Const use for class_register (Ricardo) - Identification error handling fixes (Shin'ichiro, Keith) - Improvement and cleanup for cached request handling (Christoph) - Moving towards atomic queue limits. Core changes and driver bits so far (Christoph) - Fix UAF issues in aoeblk (Chun-Yi) - Zoned fix and cleanups (Damien) - s390 dasd cleanups and fixes (Jan, Miroslav) - Block issue timestamp caching (me) - noio scope guarding for zoned IO (Johannes) - block/nvme PI improvements (Kanchan) - Ability to terminate long running discard loop (Keith) - bdev revalidation fix (Li) - Get rid of old nr_queues hack for kdump kernels (Ming) - Support for async deletion of ublk (Ming) - Improve IRQ bio recycling (Pavel) - Factor in CPU capacity for remote vs local completion (Qais) - Add shared_tags configfs entry for null_blk (Shin'ichiro - Fix for a regression in page refcounts introduced by the folio unification (Tony) - Misc fixes and cleanups (Arnd, Colin, John, Kunwu, Li, Navid, Ricardo, Roman, Tang, Uwe) * tag 'for-6.9/block-20240310' of git://git.kernel.dk/linux: (221 commits) block: partitions: only define function mac_fix_string for CONFIG_PPC_PMAC block/swim: Convert to platform remove callback returning void cdrom: gdrom: Convert to platform remove callback returning void block: remove disk_stack_limits md: remove mddev->queue md: don't initialize queue limits md/raid10: use the atomic queue limit update APIs md/raid5: use the atomic queue limit update APIs md/raid1: use the atomic queue limit update APIs md/raid0: use the atomic queue limit update APIs md: add queue limit helpers md: add a mddev_is_dm helper md: add a mddev_add_trace_msg helper md: add a mddev_trace_remap helper bcache: move calculation of stripe_size and io_opt into bcache_device_init virtio_blk: Do not use disk_set_max_open/active_zones() aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts block: move capacity validation to blkpg_do_ioctl() block: prevent division by zero in blk_rq_stat_sum() drbd: atomically update queue limits in drbd_reconsider_queue_parameters ...

dasd: use the atomic queue limits API

2024-03-06T15:27:01+00:00

Pass the constant limits directly to blk_mq_alloc_disk, set the nonrot flag there as well, and then use the commit API to change the transfer size and logical block size dependent values. This relies on the assumption that no I/O can be pending before the devices moves into the ready state and doesn't need extra freezing for changes to the queue limits. Signed-off-by: Christoph Hellwig Reviewed-by: Stefan Haberland Link: https://lore.kernel.org/r/20240228133742.806274-4-hch@lst.de Signed-off-by: Jens Axboe

s390: port block device access to file

2024-02-25T11:05:25+00:00

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-16-adbd023e19cc@kernel.org Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

block: pass a queue_limits argument to blk_mq_alloc_disk

2024-02-13T15:56:59+00:00

Pass a queue_limits to blk_mq_alloc_disk and apply it if non-NULL. This will allow allocating queues with valid queue limits instead of setting the values one at a time later. Signed-off-by: Christoph Hellwig Reviewed-by: Keith Busch Reviewed-by: John Garry Reviewed-by: Chaitanya Kulkarni Reviewed-by: Ming Lei Reviewed-by: Damien Le Moal Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20240213073425.1621680-11-hch@lst.de Signed-off-by: Jens Axboe

s390/dasd: Remove PRINTK_HEADER and KMSG_COMPONENT definitions

2024-02-08T17:12:01+00:00

PRINTK_HEADER was mainly used to prefix log messages with the module name. Most components don't use this definition anymore. Either because there are no log messages being generated anymore, or pr_*() were replaced by dev_*(), which contains device and component information already. PRINTK_HEADER is also dropped in the function dasd_3990_erp_handle_match_erp() in dasd_3990_erp.c from a panic() call as panic() already provides all relevant information. KMSG_COMPONENT was mainly used to identify a component in a long gone kernel message catalog feature. Remove both definition since they're either not used or alternatives make the code slightly shorter and more readable. Signed-off-by: Jan Höppner Reviewed-by: Stefan Haberland Signed-off-by: Stefan Haberland Link: https://lore.kernel.org/r/20240208164248.540985-9-sth@linux.ibm.com Signed-off-by: Jens Axboe

s390/dasd: Convert to bdev_open_by_path()

2023-10-28T11:29:18+00:00

Convert dasd to use bdev_open_by_path() and pass the handle around. CC: linux-s390@vger.kernel.org CC: Christian Borntraeger CC: Sven Schnelle Acked-by: Christoph Hellwig Acked-by: Christian Brauner Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20230927093442.25915-14-jack@suse.cz Signed-off-by: Christian Brauner