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2026-06-16block: respect iov_iter::nofault flag in bio_iov_iter_bounce_write()Qu Wenruo
For the incoming usage of IOMAP_DIO_BOUNCE in btrfs, btrfs has set iov_iter::nofault to prevent deadlock when a page fault is needed to read out the buffer. However bio_iov_iter_bounce_write() doesn't respect iov_iter::nofault flag, and just call a plain copy_from_iter() so it can still trigger page fault and cause deadlock in btrfs. Fix it by utilizing copy_folio_from_iter_atomic() if nofault flag is set, otherwise use copy_folio_from_iter(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/9c165a314022b61566eb247852eb773ca6c70889.1781597506.git.wqu@suse.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-06-16block: revert the iov_iter after a short copy in bio_iov_iter_bounce_write()Qu Wenruo
For the incoming IOMAP_DIO_BOUNCE flag usage inside btrfs, it's pretty easy to hit short copy inside bio_iov_iter_bounce_write(). This is because btrfs has disabled page fault to avoid certain deadlock during direct writes, and instead btrfs manually fault in the pages then retry. And inside bio_iov_iter_bounce_write(), if we hit a short write, we didn't revert the iov_iter, which can cause problems like unexpected garbage for the next retry. Revert the iov_iter after a short copy. One thing to note is that, the folio is allocated then immediately queued into the bio, so the proper revert size should be (bi_size - this_len + copied). Fixes: 8dd5e7c75d7b ("block: add helpers to bounce buffer an iov_iter into bios") Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/c400989f227343b134110773d5acaaacf7024574.1781597506.git.wqu@suse.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-06-16Merge tag 'for-7.2/block-20260615' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull block updates from Jens Axboe: - NVMe pull request via Keith: - Per-controller admin and IO timeout sysfs attributes, and letting the block layer set request timeouts (Maurizio, Maximilian) - Multipath passthrough iostats, and PCI P2PDMA enablement for multipath devices (Keith, Kiran) - A new diag sysfs attribute group exporting per-controller counters (retries, multipath failover, error counters, requeue and failure counts, reset and reconnect events) (Nilay) - FDP configuration validation and bounds check fixes (liuxixin) - Various nvmet fixes, including a pre-auth out-of-bounds read in the Discovery Get Log Page handler, auth payload bounds validation, and tcp error-path leak fixes (Bryam, Tianchu, Geliang) - nvme-tcp lockdep and workqueue fixes (Shin'ichiro, Kuniyuki, Eric) - Assorted other fixes and cleanups (John, Yao, Chao, Mateusz, Achkinazi, Wentao) - MD pull request via Yu Kuai: - raid1/raid10 fixes for a deadlock in the read error recovery path, error-path detection and bio accounting with cloned bios, and an nr_pending leak in the REQ_ATOMIC bad-block error path (Abd-Alrhman) - PCI P2PDMA propagation from member devices to the RAID device (Kiran) - dm-raid bio requeue fix, and various smaller fixes and cleanups (Benjamin, Chen, Li, Thorsten) - Enable Clang lock context analysis for the block layer, with the accompanying annotations across queue limits, the blk_holder_ops callbacks, crypto, cgroup, iocost, kyber and mq-deadline (Bart) - Block status code infrastructure work: a tagged status table, a str_to_blk_op() helper, a bio_endio_status() helper, and on top of that a new configurable block-layer error injection facility (Christoph) - DRBD netlink rework, replacing the genl_magic machinery with explicit netlink serialization and moving the DRBD UAPI headers to include/uapi/linux/ (Christoph Böhmwalder) - bvec improvements: a bvec_folio() helper and making the bvec_iter helpers proper inline functions (Willy, Christoph) - ublk cleanups and a canceling-flag fix for the disk-not-allocated case (Caleb, Ming) - Partition handling fixes: bound the AIX pp_count scan, fix an of_node refcount leak, and replace __get_free_page() with kmalloc() (Bryam, Wentao, Mike) - Convert numa_node to int in blk_mq_hw_ctx and ->init_request, and add WQ_PERCPU to the block workqueue users (Mateusz, Marco) - Block statistics and tracing: propagate in-flight to the whole disk on partition IO, export passthrough stats, and a new block_rq_tag_wait tracepoint (Tang, Keith, Aaron) - A round of removals, unexports and cleanups across bio, direct-io and the bvec helpers (Christoph) - Various driver fixes (mtip32xx use-after-free, rbd snap_count validation and strscpy conversion, nbd socket lockdep reclassify, virtio-blk zone report clamp, floppy) and a batch of MAINTAINERS email/list updates (Coly, Li, Yu, Christoph Böhmwalder) - Other little fixes and cleanups all over * tag 'for-7.2/block-20260615' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (117 commits) MAINTAINERS: Update Coly Li's email address block: check bio split for unaligned bvec nbd: Reclassify sockets to avoid lockdep circular dependency block: add configurable error injection block: add a str_to_blk_op helper block: add a "tag" for block status codes block: add a macro to initialize the status table floppy: Drop unused pnp driver data block: propagate in_flight to whole disk on partition I/O virtio-blk: clamp zone report to the report buffer capacity block: optimize I/O merge hot path with unlikely() hints drivers/block/rbd: Use strscpy() to copy strings into arrays partitions: aix: bound the pp_count scan to the ppe array block: Enable lock context analysis block/mq-deadline: Make the lock context annotations compatible with Clang block/Kyber: Make the lock context annotations compatible with Clang block/blk-mq-debugfs: Improve lock context annotations block/blk-iocost: Inline iocg_lock() and iocg_unlock() block/blk-iocost: Split ioc_rqos_throttle() block/crypto: Annotate the crypto functions ...
2026-05-29block: Add bvec_folio()Matthew Wilcox (Oracle)
This is a simple helper which replaces page_folio(bvec->bv_page). Minor improvement in readability, but the real motivation is to reduce the number of references to bvec->bv_page so that it can be changed with less work. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Leon Romanovsky <leon@kernel.org> Reviewed-by: Hannes Reinecke <hare@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: William Kucharski <william.kucharski@linux.dev> Link: https://patch.msgid.link/20260528175905.1102280-2-willy@infradead.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-28block: mark biovec_init_pool staticChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@kernel.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://patch.msgid.link/20260527150646.2349405-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-15block: unexport bio_{set,check}_pages_dirtyChristoph Hellwig
Only used in built-in code. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/20260515045547.3790129-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-15block: remove bio_copy_data_iterChristoph Hellwig
Only used by bio_copy_data, so implement that directly. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/20260515045547.3790129-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-15block: remove zero_fill_bio_iterChristoph Hellwig
Only used to implement zero_fill_bio, so directly implement that. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/20260515045547.3790129-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-13block: align down bounces biosChristoph Hellwig
Just like for the extract user pages path, we need to align down the size to the supported boundary. Fixes: 8dd5e7c75d7b ("block: add helpers to bounce buffer an iov_iter into bios") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@kernel.org> Link: https://patch.msgid.link/20260507050153.1298375-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-13block: pass a minsize argument to bio_iov_iter_bounceChristoph Hellwig
When bouncing for block size > PAGE_SIZE file systems that require file system block size alignment (e.g. zoned XFS), the bio needs to be big enough to fit an entire block. Fixes: 8dd5e7c75d7b ("block: add helpers to bounce buffer an iov_iter into bios") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@kernel.org> Link: https://patch.msgid.link/20260507050153.1298375-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-21block: only restrict bio allocation gfp mask asked to blockChristoph Hellwig
If the caller is asking for a non-blocking allocation, we should not further restrict the gfp mask, which just increases the likelihood of failures. Fixes: b520c4eef83d ("block: split bio_alloc_bioset more clearly into a fast and slowpath") Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://patch.msgid.link/20260415060813.807659-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-17block: Add WQ_PERCPU to alloc_workqueue usersMarco Crivellari
This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The refactoring is going to alter the default behavior of alloc_workqueue() to be unbound by default. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. For more details see the Link tag below. In order to keep alloc_workqueue() behavior identical, explicitly request WQ_PERCPU. Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Marco Crivellari <marco.crivellari@suse.com> Link: https://patch.msgid.link/20260223092920.60424-2-marco.crivellari@suse.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-17block: relax pgmap check in bio_add_page for compatible zone device pagesNaman Jain
bio_add_page() and bio_integrity_add_page() reject pages from different dev_pagemaps entirely, returning 0 even when those pages have compatible DMA mapping requirements. This forces callers to start a new bio when buffers span pgmap boundaries, even though the pages could safely coexist as separate bvec entries. This matters for guests where memory is registered through devm_memremap_pages() with MEMORY_DEVICE_GENERIC in multiple calls, creating separate dev_pagemaps for each chunk. When a direct I/O buffer spans two such chunks, bio_add_page() rejects the second page, forcing an unnecessary bio split or I/O failure. Introduce zone_device_pages_compatible() in blk.h to check whether two pages can coexist in the same bio as separate bvec entries. The block DMA iterator (blk_dma_map_iter_start) caches the P2PDMA mapping state from the first segment and applies it to all others, so P2PDMA pages from different pgmaps must not be mixed, and neither must P2PDMA and non-P2PDMA pages. All other combinations (MEMORY_DEVICE_GENERIC pages from different pgmaps, or MEMORY_DEVICE_GENERIC with normal RAM) use the same dma_map_phys path and are safe. Replace the blanket zone_device_pages_have_same_pgmap() rejection with zone_device_pages_compatible(), while keeping zone_device_pages_have_same_pgmap() as a merge guard. Pages from different pgmaps can be added as separate bvec entries but must not be coalesced into the same segment, as that would make it impossible to recover the correct pgmap via page_pgmap(). Fixes: 49580e690755 ("block: add check when merging zone device pages") Cc: stable@vger.kernel.org Signed-off-by: Naman Jain <namjain@linux.microsoft.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/20260410153414.4159050-3-namjain@linux.microsoft.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-07block: add a bio_submit_or_kill helperChristoph Hellwig
Factor the common logic for the ioctl helpers to either submit a bio or end if the process is being killed. As this is now the only user of bio_await_chain, open code that. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://patch.msgid.link/20260407140538.633364-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-07block: factor out a bio_await helperChristoph Hellwig
Add a new helper to wait for a bio and anything chained off it to complete synchronously after submitting it. This factors common code out of submit_bio_wait and bio_await_chain and will also be useful for file system code and thus is exported. Note that this will now set REQ_SYNC also for the bio_await case for consistency. Nothing should look at the flag in the end_io handler, but if something does having the flag set makes more sense. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://patch.msgid.link/20260407140538.633364-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-07block: unify the synchronous bi_end_io callbacksChristoph Hellwig
Put the bio in bio_await_chain after waiting for the completion, and share the now identical callbacks between submit_bio_wait and bio_await_chain. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://patch.msgid.link/20260407140538.633364-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-02bio: fix kmemleak false positives from percpu bio alloc cacheMing Lei
When a bio is allocated from the mempool with REQ_ALLOC_CACHE set and later completed, bio_put() places it into the per-cpu bio_alloc_cache via bio_put_percpu_cache() instead of freeing it back to the mempool/slab. The slab allocation remains tracked by kmemleak, but the only reference to the bio is through the percpu cache's free_list, which kmemleak fails to trace through percpu memory. This causes kmemleak to report the cached bios as unreferenced objects. Use symmetric kmemleak_free()/kmemleak_alloc() calls to properly track bios across percpu cache transitions: - bio_put_percpu_cache: call kmemleak_free() when a bio enters the cache, unregistering it from kmemleak tracking. - bio_alloc_percpu_cache: call kmemleak_alloc() when a bio is taken from the cache for reuse, re-registering it so that genuine leaks of reused bios remain detectable. - __bio_alloc_cache_prune: call kmemleak_alloc() before bio_free() so that kmem_cache_free()'s internal kmemleak_free() has a matching allocation to pair with. Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://patch.msgid.link/20260326144058.2392319-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-23block: fix bio_alloc_bioset slowpath GFP handlingVasily Gorbik
bio_alloc_bioset() first strips __GFP_DIRECT_RECLAIM from the optimistic fast allocation attempt with try_alloc_gfp(). If that fast path fails, the slowpath checks saved_gfp to decide whether blocking allocation is allowed, but then still calls mempool_alloc() with the stripped gfp mask. That can lead to a NULL bio pointer being passed into bio_init(). Fix the slowpath by using saved_gfp for the bio and bvec mempool allocations. Fixes: b520c4eef83d ("block: split bio_alloc_bioset more clearly into a fast and slowpath") Reported-by: syzbot+09ddb593eea76a158f42@syzkaller.appspotmail.com Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://patch.msgid.link/p01.gc6e9ad5845ad.ttca29g@ub.hpns Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17block: reject zero length in bio_add_page()Qu Wenruo
The function bio_add_page() returns the number of bytes added to the bio, and if that failed it should return 0. However there is a special quirk, if a caller is passing a page with length 0, that function will always return 0 but with different results: - The page is added to the bio If there is enough bvec slot or the folio can be merged with the last bvec. The return value 0 is just the length passed in, which is also 0. - The page is not added to the bio If the page is not mergeable with the last bvec, or there is no bvec slot available. The return value 0 means page is not added into the bio. Unfortunately the caller is not able to distinguish the above two cases, and will treat the 0 return value as page addition failure. In that case, this can lead to the double releasing of the last page: - By the bio cleanup Which normally goes through every page of the bio, including the last page which is added into the bio. - By the caller Which believes the page is not added into the bio, thus would manually release the page. I do not think anyone should call bio_add_folio()/bio_add_page() with zero length, but idiots like me can still show up. So add an extra WARN_ON_ONCE() check for zero length and rejects it early to avoid double freeing. Signed-off-by: Qu Wenruo <wqu@suse.com> Link: https://patch.msgid.link/bc2223c080f38d0b63f968f605c918181c840f40.1773734749.git.wqu@suse.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17block: remove bvec_freeChristoph Hellwig
bvec_free is only called by bio_free, so inline it there. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://patch.msgid.link/20260316161144.1607877-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17block: split bio_alloc_bioset more clearly into a fast and slowpathChristoph Hellwig
bio_alloc_bioset tries non-waiting slab allocations first for the bio and bvec array, but does so in a somewhat convoluted way. Restructure the function so that it first open codes these slab allocations, and then falls back to the mempools with the original gfp mask. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://patch.msgid.link/20260316161144.1607877-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17block: mark bvec_{alloc,free} staticChristoph Hellwig
Only used in bio.c these days. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://patch.msgid.link/20260316161144.1607877-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09Merge branch 'for-7.1/block-integrity' into for-7.1/blockJens Axboe
Merge in integrity changes which are also landing in the VFS tree as dependencies for fs related changes. * for-7.1/block-integrity: block: pass a maxlen argument to bio_iov_iter_bounce block: add fs_bio_integrity helpers block: make max_integrity_io_size public block: prepare generation / verification helpers for fs usage block: add a bdev_has_integrity_csum helper block: factor out a bio_integrity_setup_default helper block: factor out a bio_integrity_action helper
2026-03-09block: Correct comments on bio_alloc_clone() and bio_init_clone()John Garry
Correct the comments that the cloned bio must be freed before the memory pointed to by @bio_src->bi_io_vecs (is freed). Christoph Hellwig contributed most the of the update wording. Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-09block: pass a maxlen argument to bio_iov_iter_bounceChristoph Hellwig
Allow the file system to limit the size processed in a single bounce operation. This is needed when generating integrity data so that the size of a single integrity segment can't overflow. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Kanchan Joshi <joshi.k@samsung.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Tested-by: Anuj Gupta <anuj20.g@samsung.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-21Convert 'alloc_obj' family to use the new default GFP_KERNEL argumentLinus Torvalds
This was done entirely with mindless brute force, using git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' | xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/' to convert the new alloc_obj() users that had a simple GFP_KERNEL argument to just drop that argument. Note that due to the extreme simplicity of the scripting, any slightly more complex cases spread over multiple lines would not be triggered: they definitely exist, but this covers the vast bulk of the cases, and the resulting diff is also then easier to check automatically. For the same reason the 'flex' versions will be done as a separate conversion. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21treewide: Replace kmalloc with kmalloc_obj for non-scalar typesKees Cook
This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-12block: fix folio leak in bio_iov_iter_bounce_read()Jens Axboe
If iov_iter_extract_bvecs() returns an error or zero bytes extracted, then the folio allocated is leaked on return. Ensure it's put before returning. Fixes: 8dd5e7c75d7b ("block: add helpers to bounce buffer an iov_iter into bios") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-09Merge tag 'for-7.0/block-stable-pages-20260206' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux 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
2026-02-09Merge tag 'for-7.0/block-20260206' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux 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 ...
2026-01-28block: add helpers to bounce buffer an iov_iter into biosChristoph Hellwig
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 <hch@lst.de> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Tested-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-28block: remove bio_release_pageChristoph Hellwig
Merge bio_release_page into the only remaining caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Tested-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-28iov_iter: extract a iov_iter_extract_bvecs helper from bio codeChristoph Hellwig
Massage __bio_iov_iter_get_pages so that it doesn't need the bio, and move it to lib/iov_iter.c so that it can be used by block code for other things than filling a bio and by other subsystems like netfs. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-28block: open code bio_add_page and fix handling of mismatching P2P rangesChristoph Hellwig
bio_add_page fails to add data to the bio when mixing P2P with non-P2P ranges, or ranges that map to different P2P providers. In that case it will trigger that WARN_ON and return an error up the chain instead of simply starting a new bio as intended. Fix this by open coding bio_add_page and handling this case explicitly. While doing so, stop merging physical contiguous data that belongs to multiple folios. While this merge could lead to more efficient bio packing in some case, dropping will allow to remove handling of this corner case in other places and make the code more robust. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Tested-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-28block: refactor get_contig_folio_lenChristoph Hellwig
Move all of the logic to find the contigous length inside a folio into get_contig_folio_len instead of keeping some of it in the caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Tested-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-28block: add a BIO_MAX_SIZE constant and use itChristoph Hellwig
Currently the only constant for the maximum bio size is BIO_MAX_SECTORS, which is in units of 512-byte sectors, but a lot of user need a byte limit. Add a BIO_MAX_SIZE constant, redefine BIO_MAX_SECTORS in terms of it, and switch all bio-related uses of UINT_MAX for the maximum size to use the symbolic names instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-21block: add a bio_reuse helperChristoph Hellwig
Add a helper to allow an existing bio to be resubmitted without having to re-add the payload. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2026-01-07block: don't initialize bi_vcnt for cloned bio in bio_iov_bvec_set()Ming Lei
bio_iov_bvec_set() creates a cloned bio that borrows a bvec array from an iov_iter. For cloned bios, bi_vcnt is meaningless because iteration is controlled entirely by bi_iter (bi_idx, bi_size, bi_bvec_done), not by bi_vcnt. Remove the incorrect bi_vcnt assignment. Explicitly initialize bi_iter.bi_idx to 0 to ensure iteration starts at the first bvec. While bi_idx is typically already zero from bio initialization, making this explicit improves clarity and correctness. This change also avoids accessing iter->nr_segs, which is an iov_iter implementation detail that block code should not depend on. Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-07block: use bvec iterator helper for bio_may_need_split()Ming Lei
bio_may_need_split() uses bi_vcnt to determine if a bio has a single segment, but bi_vcnt is unreliable for cloned bios. Cloned bios share the parent's bi_io_vec array but iterate over a subset via bi_iter, so bi_vcnt may not reflect the actual segment count being iterated. Replace the bi_vcnt check with bvec iterator access via __bvec_iter_bvec(), comparing bi_iter.bi_size against the current bvec's length. This correctly handles both cloned and non-cloned bios. Move bi_io_vec into the first cache line adjacent to bi_iter. This is a sensible layout since bi_io_vec and bi_iter are commonly accessed together throughout the block layer - every bvec iteration requires both fields. This displaces bi_end_io to the second cache line, which is acceptable since bi_end_io and bi_private are always fetched together in bio_endio() anyway. The struct layout change requires bio_reset() to preserve and restore bi_io_vec across the memset, since it now falls within BIO_RESET_BYTES. Nitesh verified that this patch doesn't regress NVMe 512-byte IO perf [1]. Link: https://lore.kernel.org/linux-block/20251220081607.tvnrltcngl3cc2fh@green245.gost/ [1] Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-12-09block: prohibit calls to bio_chain_endioShida Zhang
Now that all potential callers of bio_chain_endio have been eliminated, completely prohibit any future calls to this function. Suggested-by: Ming Lei <ming.lei@redhat.com> Suggested-by: Andreas Gruenbacher <agruenba@redhat.com> Suggested-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Shida Zhang <zhangshida@kylinos.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-12-04block: enable per-cpu bio cache by defaultFengnan Chang
Since after commit 12e4e8c7ab59 ("io_uring/rw: enable bio caches for IRQ rw"), bio_put is safe for task and irq context, bio_alloc_bioset is safe for task context and no one calls in irq context, so we can enable per cpu bio cache by default. Benchmarked with t/io_uring and ext4+nvme: taskset -c 6 /root/fio/t/io_uring -p0 -d128 -b4096 -s1 -c1 -F1 -B1 -R1 -X1 -n1 -P1 /mnt/testfile base IOPS is 562K, patch IOPS is 574K. The CPU usage of bio_alloc_bioset decrease from 1.42% to 1.22%. The worst case is allocate bio in CPU A but free in CPU B, still use t/io_uring and ext4+nvme: base IOPS is 648K, patch IOPS is 647K. Also use fio test ext4/xfs with libaio/sync/io_uring on null_blk and nvme, no obvious performance regression. Signed-off-by: Fengnan Chang <changfengnan@bytedance.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-06block: accumulate memory segment gaps per bioKeith Busch
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 <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-07block: rename bio_iov_iter_get_pages_aligned to bio_iov_iter_get_pagesChristoph Hellwig
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 <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10block: cleanup bio_issueYu Kuai
Now that bio->bi_issue is only used by blk-iolatency to get bio issue time, replace bio_issue with u64 time directly and remove bio_issue to make code cleaner. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09block: align the bio after building itKeith Busch
Instead of ensuring each vector is block size aligned while constructing the bio, just ensure the entire size is aligned after it's built. This makes getting bio pages more flexible to accepting device valid io vectors that would otherwise get rejected by alignment checks. Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09block: add size alignment to bio_iov_iter_get_pagesKeith Busch
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 <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09block: remove the bi_inline_vecs variable sized array from struct bioChristoph Hellwig
Bios are embedded into other structures, and at least spare is unhappy about embedding structures with variable sized arrays. There's no real need to the array anyway, we can replace it with a helper pointing to the memory just behind the bio, and with the previous cleanups there is very few site doing anything special with it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: John Garry <john.g.garry@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09block: add a bio_init_inline helperChristoph Hellwig
Just a simpler wrapper around bio_init for callers that want to initialize a bio with inline bvecs. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-25blk-mq: remove REQ_P2PDMA flagKeith Busch
It's not serving any particular purpose. pci_p2pdma_state() already has all the appropriate checks, so the config and flag checks are not guarding anything. Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Kanchan Joshi <joshi.k@samsung.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20250813153153.3260897-5-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-07-31Merge tag 'mm-stable-2025-07-30-15-25' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...