kernel/linux.git/drivers/s390/block, branch v6.18.48

s390/dasd: Fix undersized format-check buffer

2026-08-09T18:25:19+00:00

commit 7f40b346462f563a0d6e841a77b5163d2a882a04 upstream. fmt_buffer_size in dasd_eckd_check_device_format() is declared as int, even though one of the multiplicands, sizeof(struct eckd_count), is a size_t. The expression trkcount * rpt_max * sizeof(struct eckd_count) is therefore correctly evaluated at 64-bit width, but the result is silently truncated when it is stored back into the 32-bit fmt_buffer_size variable. For a sufficiently large track range (start_unit/stop_unit are caller-controlled) this truncation yields a buffer size far smaller than the number of tracks actually requested. kzalloc() then succeeds with an undersized allocation, while the subsequent channel program build still operates on the untruncated track count and writes past the end of that buffer. Compute the buffer size with check_mul_overflow() and keep it in a size_t, so that a value that no longer fits results in -EINVAL instead of a silently truncated allocation size. Fixes: 8fd575200db5 ("s390/dasd: Add new ioctl BIODASDCHECKFMT") Cc: stable@vger.kernel.org #4.7 Reviewed-by: Jan Höppner Signed-off-by: Stefan Haberland Link: https://patch.msgid.link/20260727142840.567286-4-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

s390/dasd: Fix potential NULL pointer dereference

2026-08-09T18:25:19+00:00

commit 9973026f572db6b67570cadc30942f3014e41079 upstream. dasd_release_space() checks the implementation of the is_ese() discipline function before calling it to determine if a given device is an ESE DASD. The current usage of the logical AND operator will lead to a NULL pointer dereference as the function is called even if the function pointer is NULL. Fix this by using the logical OR operator. Fixes: 91dc4a197569 ("s390/dasd: Add new ioctl to release space") Cc: stable@vger.kernel.org # v5.3+ Reported-by: Vasily Gorbik Acked-by: Eduard Shishkin Reviewed-by: Stefan Haberland Signed-off-by: Jan Höppner Signed-off-by: Stefan Haberland Link: https://patch.msgid.link/20260727142840.567286-3-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

s390/dasd: Copy detected format information to secondary device

2026-03-19T15:08:43+00:00

commit 4c527c7e030672efd788d0806d7a68972a7ba3c1 upstream. During online processing for a DASD device an IO operation is started to determine the format of the device. CDL format contains specifically sized blocks at the beginning of the disk. For a PPRC secondary device no real IO operation is possible therefore this IO request can not be started and this step is skipped for online processing of secondary devices. This is generally fine since the secondary is a copy of the primary device. In case of an additional partition detection that is run after a swap operation the format information is needed to properly drive partition detection IO. Currently the information is not passed leading to IO errors during partition detection and a wrongly detected partition table which in turn might lead to data corruption on the disk with the wrong partition table. Fix by passing the format information from primary to secondary device. Fixes: 413862caad6f ("s390/dasd: add copy pair swap capability") Cc: stable@vger.kernel.org #6.1 Reviewed-by: Jan Hoeppner Acked-by: Eduard Shishkin Signed-off-by: Stefan Haberland Link: https://patch.msgid.link/20260310142330.4080106-3-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

s390/dasd: Move quiesce state with pprc swap

2026-03-19T15:08:43+00:00

commit 40e9cd4ae8ec43b107ed2bff422a8fa39dcf4e4b upstream. Quiesce and resume is a mechanism to suspend operations on DASD devices. In the context of a controlled copy pair swap operation, the quiesce operation is usually issued before the actual swap and a resume afterwards. During the swap operation, the underlying device is exchanged. Therefore, the quiesce flag must be moved to the secondary device to ensure a consistent quiesce state after the swap. The secondary device itself cannot be suspended separately because there is no separate block device representation for it. Fixes: 413862caad6f ("s390/dasd: add copy pair swap capability") Cc: stable@vger.kernel.org #6.1 Reviewed-by: Jan Hoeppner Signed-off-by: Stefan Haberland Link: https://patch.msgid.link/20260310142330.4080106-2-sth@linux.ibm.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

s390/dasd: Fix gendisk parent after copy pair swap

2026-01-02T11:57:08+00:00

commit c943bfc6afb8d0e781b9b7406f36caa8bbf95cb9 upstream. After a copy pair swap the block device's "device" symlink points to the secondary CCW device, but the gendisk's parent remained the primary, leaving /sys/block/ under the wrong parent. Move the gendisk to the secondary's device with device_move(), keeping the sysfs topology consistent after the swap. Fixes: 413862caad6f ("s390/dasd: add copy pair swap capability") Cc: stable@vger.kernel.org #6.1 Reviewed-by: Jan Hoeppner Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2025-10-02T17:16:56+00:00

Pull block updates from Jens Axboe: - NVMe pull request via Keith: - FC target fixes (Daniel) - Authentication fixes and updates (Martin, Chris) - Admin controller handling (Kamaljit) - Target lockdep assertions (Max) - Keep-alive updates for discovery (Alastair) - Suspend quirk (Georg) - MD pull request via Yu: - Add support for a lockless bitmap. A key feature for the new bitmap are that the IO fastpath is lockless. If a user issues lots of write IO to the same bitmap bit in a short time, only the first write has additional overhead to update bitmap bit, no additional overhead for the following writes. By supporting only resync or recover written data, means in the case creating new array or replacing with a new disk, there is no need to do a full disk resync/recovery. - Switch ->getgeo() and ->bios_param() to using struct gendisk rather than struct block_device. - Rust block changes via Andreas. This series adds configuration via configfs and remote completion to the rnull driver. The series also includes a set of changes to the rust block device driver API: a few cleanup patches, and a few features supporting the rnull changes. The series removes the raw buffer formatting logic from `kernel::block` and improves the logic available in `kernel::string` to support the same use as the removed logic. - floppy arch cleanups - Reduce the number of dereferencing needed for ublk commands - Restrict supported sockets for nbd. Mostly done to eliminate a class of issues perpetually reported by syzbot, by using nonsensical socket setups. - A few s390 dasd block fixes - Fix a few issues around atomic writes - Improve DMA interation for integrity requests - Improve how iovecs are treated with regards to O_DIRECT aligment constraints. We used to require each segment to adhere to the constraints, now only the request as a whole needs to. - Clean up and improve p2p support, enabling use of p2p for metadata payloads - Improve locking of request lookup, using SRCU where appropriate - Use page references properly for brd, avoiding very long RCU sections - Fix ordering of recursively submitted IOs - Clean up and improve updating nr_requests for a live device - Various fixes and cleanups * tag 'for-6.18/block-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (164 commits) s390/dasd: enforce dma_alignment to ensure proper buffer validation s390/dasd: Return BLK_STS_INVAL for EINVAL from do_dasd_request ublk: remove redundant zone op check in ublk_setup_iod() nvme: Use non zero KATO for persistent discovery connections nvmet: add safety check for subsys lock nvme-core: use nvme_is_io_ctrl() for I/O controller check nvme-core: do ioccsz/iorcsz validation only for I/O controllers nvme-core: add method to check for an I/O controller blk-cgroup: fix possible deadlock while configuring policy blk-mq: fix null-ptr-deref in blk_mq_free_tags() from error path blk-mq: Fix more tag iteration function documentation selftests: ublk: fix behavior when fio is not installed ublk: don't access ublk_queue in ublk_unmap_io() ublk: pass ublk_io to __ublk_complete_rq() ublk: don't access ublk_queue in ublk_need_complete_req() ublk: don't access ublk_queue in ublk_check_commit_and_fetch() ublk: don't pass ublk_queue to ublk_fetch() ublk: don't access ublk_queue in ublk_config_io_buf() ublk: don't access ublk_queue in ublk_check_fetch_buf() ublk: pass q_id and tag to __ublk_check_and_get_req() ...

s390/dasd: enforce dma_alignment to ensure proper buffer validation

2025-09-25T16:34:30+00:00

The block layer validates buffer alignment using the device's dma_alignment value. If dma_alignment is smaller than logical_block_size(bp_block) -1, misaligned buffer incorrectly pass validation and propagate to the lower-level driver. This patch adjusts dma_alignment to be at least logical_block_size -1, ensuring that misalignment buffers are properly rejected at the block layer and do not reach the DASD driver unnecessarily. Fixes: 2a07bb64d801 ("s390/dasd: Remove DMA alignment") Reviewed-by: Stefan Haberland Cc: stable@vger.kernel.org #6.11+ Signed-off-by: Jaehoon Kim Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe

s390/dasd: Return BLK_STS_INVAL for EINVAL from do_dasd_request

2025-09-25T16:34:30+00:00

Currently, if CCW request creation fails with -EINVAL, the DASD driver returns BLK_STS_IOERR to the block layer. This can happen, for example, when a user-space application such as QEMU passes a misaligned buffer, but the original cause of the error is masked as a generic I/O error. This patch changes the behavior so that -EINVAL is returned as BLK_STS_INVAL, allowing user space to properly detect alignment issues instead of interpreting them as I/O errors. Reviewed-by: Stefan Haberland Cc: stable@vger.kernel.org #6.11+ Signed-off-by: Jaehoon Kim Signed-off-by: Stefan Haberland Signed-off-by: Jens Axboe

s390/dcssblk: Add DAX support

2025-09-16T14:56:39+00:00

With ZONE_DEVICE now available for s390, struct pages can be allocated for proper DAX support in dcssblk driver via devm_memremap_pages(). Adding struct pages for a range requires that the range is aligned to SUBSECTION_SIZE, which is defined as 2 MB in common code. Therefore, only enable DAX support and allocate struct pages for DCSS ranges that are aligned to 2 MB. Signed-off-by: Gerald Schaefer Acked-by: Heiko Carstens Reviewed-by: Alexander Gordeev Signed-off-by: Alexander Gordeev

block: switch ->getgeo() to struct gendisk

2025-08-13T06:59:29+00:00

Instances are happier that way and it makes more sense anyway - the only part of the result that is related to partition we are given is the start sector, and that has been filled in by the caller. Everything else is a function of the disk. Only one instance (DASD) is ever looking at anything other than bdev->bd_disk and that one is trivial to adjust. Reviewed-by: Martin K. Petersen Reviewed-by: Christoph Hellwig Acked-by: Jens Axboe Signed-off-by: Al Viro