kernel/linux.git/include/linux/bio.h, branch v7.0-rc7

Merge tag 'for-7.0/block-stable-pages-20260206' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2026-02-10T02:14:52+00:00

Pull bounce buffer dio for stable pages from Jens Axboe: "This adds support for bounce buffering of dio for stable pages. This was all done by Christoph. In his words: This series tries to address the problem that under I/O pages can be modified during direct I/O, even when the device or file system require stable pages during I/O to calculate checksums, parity or data operations. It does so by adding block layer helpers to bounce buffer an iov_iter into a bio, then wires that up in iomap and ultimately XFS. The reason that the file system even needs to know about it, is because reads need a user context to copy the data back, and the infrastructure to defer ioends to a workqueue currently sits in XFS. I'm going to look into moving that into ioend and enabling it for other file systems. Additionally btrfs already has it's own infrastructure for this, and actually an urgent need to bounce buffer, so this should be useful there and could be wire up easily. In fact the idea comes from patches by Qu that did this in btrfs. This patch fixes all but one xfstests failures on T10 PI capable devices (generic/095 seems to have issues with a mix of mmap and splice still, I'm looking into that separately), and make qemu VMs running Windows, or Linux with swap enabled fine on an XFS file on a device using PI. Performance numbers on my (not exactly state of the art) NVMe PI test setup: Sequential reads using io_uring, QD=16. Bandwidth and CPU usage (usr/sys): | size | zero copy | bounce | +------+--------------------------+--------------------------+ | 4k | 1316MiB/s (12.65/55.40%) | 1081MiB/s (11.76/49.78%) | | 64K | 3370MiB/s ( 5.46/18.20%) | 3365MiB/s ( 4.47/15.68%) | | 1M | 3401MiB/s ( 0.76/23.05%) | 3400MiB/s ( 0.80/09.06%) | +------+--------------------------+--------------------------+ Sequential writes using io_uring, QD=16. Bandwidth and CPU usage (usr/sys): | size | zero copy | bounce | +------+--------------------------+--------------------------+ | 4k | 882MiB/s (11.83/33.88%) | 750MiB/s (10.53/34.08%) | | 64K | 2009MiB/s ( 7.33/15.80%) | 2007MiB/s ( 7.47/24.71%) | | 1M | 1992MiB/s ( 7.26/ 9.13%) | 1992MiB/s ( 9.21/19.11%) | +------+--------------------------+--------------------------+ Note that the 64k read numbers look really odd to me for the baseline zero copy case, but are reproducible over many repeated runs. The bounce read numbers should further improve when moving the PI validation to the file system and removing the double context switch, which I have patches for that will sent out soon" * tag 'for-7.0/block-stable-pages-20260206' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: xfs: use bounce buffering direct I/O when the device requires stable pages iomap: add a flag to bounce buffer direct I/O iomap: support ioends for direct reads iomap: rename IOMAP_DIO_DIRTY to IOMAP_DIO_USER_BACKED iomap: free the bio before completing the dio iomap: share code between iomap_dio_bio_end_io and iomap_finish_ioend_direct iomap: split out the per-bio logic from iomap_dio_bio_iter iomap: simplify iomap_dio_bio_iter iomap: fix submission side handling of completion side errors block: add helpers to bounce buffer an iov_iter into bios block: remove bio_release_page iov_iter: extract a iov_iter_extract_bvecs helper from bio code block: open code bio_add_page and fix handling of mismatching P2P ranges block: refactor get_contig_folio_len block: add a BIO_MAX_SIZE constant and use it

Merge tag 'for-7.0/block-20260206' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux

2026-02-10T01:57:21+00:00

Pull block updates from Jens Axboe: - Support for batch request processing for ublk, improving the efficiency of the kernel/ublk server communication. This can yield nice 7-12% performance improvements - Support for integrity data for ublk - Various other ublk improvements and additions, including a ton of selftests additions and updated - Move the handling of blk-crypto software fallback from below the block layer to above it. This reduces the complexity of dealing with bio splitting - Series fixing a number of potential deadlocks in blk-mq related to the queue usage counter and writeback throttling and rq-qos debugfs handling - Add an async_depth queue attribute, to resolve a performance regression that's been around for a qhilw related to the scheduler depth handling - Only use task_work for IOPOLL completions on NVMe, if it is necessary to do so. An earlier fix for an issue resulted in all these completions being punted to task_work, to guarantee that completions were only run for a given io_uring ring when it was local to that ring. With the new changes, we can detect if it's necessary to use task_work or not, and avoid it if possible. - rnbd fixes: - Fix refcount underflow in device unmap path - Handle PREFLUSH and NOUNMAP flags properly in protocol - Fix server-side bi_size for special IOs - Zero response buffer before use - Fix trace format for flags - Add .release to rnbd_dev_ktype - MD pull requests via Yu Kuai - Fix raid5_run() to return error when log_init() fails - Fix IO hang with degraded array with llbitmap - Fix percpu_ref not resurrected on suspend timeout in llbitmap - Fix GPF in write_page caused by resize race - Fix NULL pointer dereference in process_metadata_update - Fix hang when stopping arrays with metadata through dm-raid - Fix any_working flag handling in raid10_sync_request - Refactor sync/recovery code path, improve error handling for badblocks, and remove unused recovery_disabled field - Consolidate mddev boolean fields into mddev_flags - Use mempool to allocate stripe_request_ctx and make sure max_sectors is not less than io_opt in raid5 - Fix return value of mddev_trylock - Fix memory leak in raid1_run() - Add Li Nan as mdraid reviewer - Move phys_vec definitions to the kernel types, mostly in preparation for some VFIO and RDMA changes - Improve the speed for secure erase for some devices - Various little rust updates - Various other minor fixes, improvements, and cleanups * tag 'for-7.0/block-20260206' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (162 commits) blk-mq: ABI/sysfs-block: fix docs build warnings selftests: ublk: organize test directories by test ID block: decouple secure erase size limit from discard size limit block: remove redundant kill_bdev() call in set_blocksize() blk-mq: add documentation for new queue attribute async_dpeth block, bfq: convert to use request_queue->async_depth mq-deadline: covert to use request_queue->async_depth kyber: covert to use request_queue->async_depth blk-mq: add a new queue sysfs attribute async_depth blk-mq: factor out a helper blk_mq_limit_depth() blk-mq-sched: unify elevators checking for async requests block: convert nr_requests to unsigned int block: don't use strcpy to copy blockdev name blk-mq-debugfs: warn about possible deadlock blk-mq-debugfs: add missing debugfs_mutex in blk_mq_debugfs_register_hctxs() blk-mq-debugfs: remove blk_mq_debugfs_unregister_rqos() blk-mq-debugfs: make blk_mq_debugfs_register_rqos() static blk-rq-qos: fix possible debugfs_mutex deadlock blk-mq-debugfs: factor out a helper to register debugfs for all rq_qos blk-wbt: fix possible deadlock to nest pcpu_alloc_mutex under q_usage_counter ...

block: add helpers to bounce buffer an iov_iter into bios

2026-01-28T12:16:39+00:00

Add helpers to implement bounce buffering of data into a bio to implement direct I/O for cases where direct user access is not possible because stable in-flight data is required. These are intended to be used as easily as bio_iov_iter_get_pages for the zero-copy path. The write side is trivial and just copies data into the bounce buffer. The read side is a lot more complex because it needs to perform the copy from the completion context, and without preserving the iov_iter through the call chain. It steals a trick from the integrity data user interface and uses the first vector in the bio for the bounce buffer data that is fed to the block I/O stack, and uses the others to record the user buffer fragments. Signed-off-by: Christoph Hellwig Reviewed-by: Anuj Gupta Reviewed-by: Damien Le Moal Reviewed-by: Johannes Thumshirn Tested-by: Anuj Gupta Reviewed-by: Martin K. Petersen Reviewed-by: Darrick J. Wong Signed-off-by: Jens Axboe

block: remove bio_last_bvec_all

2026-01-27T04:07:48+00:00

There are no more callers of this function after commit f6b2d8b134b2413 ("btrfs: track the next file offset in struct btrfs_bio_ctrl"), so remove the function. Signed-off-by: Keith Busch Reviewed-by: Kanchan Joshi Signed-off-by: Jens Axboe

block: add a bio_reuse helper

2026-01-21T11:57:16+00:00

Add a helper to allow an existing bio to be resubmitted without having to re-add the payload. Signed-off-by: Christoph Hellwig Reviewed-by: Jens Axboe Reviewed-by: Hans Holmberg Reviewed-by: Carlos Maiolino Reviewed-by: Damien Le Moal Reviewed-by: Darrick J. Wong Signed-off-by: Carlos Maiolino

block: move around bio flagging helpers

2025-12-12T19:36:44+00:00

We'll need bio_flagged() earlier in bio.h for later patches, move it together with all related helpers, and mark the bio_flagged()'s bio argument as const. Signed-off-by: Pavel Begunkov Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: accumulate memory segment gaps per bio

2025-11-07T01:11:58+00:00

The blk-mq dma iterator has an optimization for requests that align to the device's iommu merge boundary. This boundary may be larger than the device's virtual boundary, but the code had been depending on that queue limit to know ahead of time if the request is guaranteed to align to that optimization. Rather than rely on that queue limit, which many devices may not report, save the lowest set bit of any boundary gap between each segment in the bio while checking the segments. The request stores the value for merging and quickly checking per io if the request can use iova optimizations. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe

block: rename bio_iov_iter_get_pages_aligned to bio_iov_iter_get_pages

2025-10-07T14:05:44+00:00

Now that the bio_iov_iter_get_pages is free again, use it instead of the more complicated now. Also drop the unused export. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Johannes Thumshirn Reviewed-by: Keith Busch Reviewed-by: Qu Wenruo Signed-off-by: Jens Axboe

block: remove bio_iov_iter_get_pages

2025-10-07T14:05:44+00:00

Switch the only caller to bio_iov_iter_get_pages, and explain why it does not have any alignment requirements. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Johannes Thumshirn Reviewed-by: Keith Busch Reviewed-by: Qu Wenruo Signed-off-by: Jens Axboe

block: add size alignment to bio_iov_iter_get_pages

2025-09-09T16:27:01+00:00

The block layer tries to align bio vectors to the block device's logical block size. Some cases don't have a block device, or we may need to align to something larger, which we can't derive it from the queue limits. Have the caller specify what they want, or allow any length alignment if nothing was specified. Since the most common use case relies on the block device's limits, a helper function is provided. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe