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2026-06-16Merge tag 'for-7.2/io_uring-20260615' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull io_uring updates from Jens Axboe: - Rework the task_work infrastructure. Both the local (DEFER_TASKRUN) and the normal (tctx) task_work lists were llist based, which is LIFO ordered, and hence each run had to do an O(n) list reversal pass first to restore queue order. Additionally, to cap the amount of task_work run, each method needed a retry list as well. Add a lockless MPCS FIFO queue (based on Dmitry Vyukov's intrusive MPSC algorithm) and switch both task_work lists to it. It performs better than llists and we can then also ditch the retry lists as well as entries are popped one-at-the-time. On top of those changes, run the tctx fallback task_work directly and remove the now-unused per-ctx fallback machinery entirely. - zcrx user notifications. Add a mechanism for zcrx to communicate conditions back to userspace via a dedicated CQE, with the initial users being notification on running out of buffers and on a frag copy fallback, plus shared-memory notification statistics. Alongside that, a series of zcrx reliability and cleanup fixes: more reliable scrubbing, poisoning pointers on unregistration, dropping an extra ifq close, adding a ctx back-pointer, reordering fd allocation in the export path, and killing a dead 'sock' member. - Allow using io_uring registered buffers for plain SEND and RECV, not just for the zero-copy send path. This enables targets like ublk's NBD backend to push/pull IO data directly to/from a registered buffer over a plain send/recv on a TCP socket. - Registered buffer improvements: account huge pages correctly, bump the io_mapped_ubuf length field to size_t, and raise the previous 1GB registered buffer size limit. - Restrict the ctx access exposed to io_uring BPF struct_ops programs by handing them an opaque type rather than the full io_ring_ctx, and add a separate MAINTAINERS entry for the bpf-ops code. - Allow opcode filtering on IORING_OP_CONNECT. - Validate ring-provided buffer addresses with access_ok(), and align the legacy buffer add limit with MAX_BIDS_PER_BGID. - Various other cleanups and minor fixes, including avoiding msghdr async data on connect/bind, dropping async_size for OP_LISTEN, making the POLL_FIRST receive side checks consistent, re-checking IO_WQ_BIT_EXIT for each linked work item, and using trace_call__##name() at guarded tracepoint call sites. * tag 'for-7.2/io_uring-20260615' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (31 commits) io_uring/bpf-ops: add a separate maintainer entry io_uring/net: make POLL_FIRST receive side checks consistent io_uring: remove the per-ctx fallback task_work machinery io_uring: run the tctx task_work fallback directly io_uring: switch normal task_work to a mpscq io_uring: switch local task_work to a mpscq io_uring/mpscq: add lockless multi-producer, single-consumer FIFO queue io_uring: grab RCU read lock marking task run io_uring/zcrx: kill dead 'sock' member in struct io_zcrx_args io_uring/kbuf: validate ring provided buffer addresses with access_ok() io_uring/net: support registered buffer for plain send and recv io_uring/nop: Drop a wrong comment in struct io_nop io_uring/net: Remove async_size for OP_LISTEN io_uring/net: Avoid msghdr on op_connect/op_bind async data io_uring/bpf-ops: restrict ctx access to BPF io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item io_uring/kbuf: align legacy buffer add limit with MAX_BIDS_PER_BGID io_uring/zcrx: add shared-memory notification statistics io_uring/zcrx: notify user on frag copy fallback io_uring/zcrx: notify user when out of buffers ...
2026-06-08io_uring/kbuf: validate ring provided buffer addresses with access_ok()Jens Axboe
Commit: 809b997a5ce9 ("x86-64/arm64/powerpc: clean up and rename __copy_from_user_flushcache") sanitized that any provided copy helper should separately validate destination and source addresses, but we should also ensure that anything that is retrieved from a buffer is validated upfront. For ring provided buffers, always include an access_ok() when grabbing a new buffer. Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-06-07io_uring/kbuf: don't truncate end buffer for bundlesJens Axboe
If buffers have been peeked for a bundle receive, the kernel will truncate the end buffer, if the available length is shorter than the buffer itself. This is unnecessary, as applications iterating bundle receives must always use the minimum size of the buffer length and the remaining number of bytes in the bundle. The examples in liburing do that as well, eg examples/proxy.c. If the kernel does truncate this buffer AND the current transfer fails, then the buffer will be left with a smaller size than what is otherwise available. Just remove the buffer truncation, as it's not necessary in the first place. Link: https://lore.kernel.org/io-uring/CAAEr8jbY60noGj1fw_k91UJRBkyiRVoS6=nLhZ7Svwidjn4CAA@mail.gmail.com/ Reported-by: Federico Brasili <federico.brasili@gmail.com> Cc: stable@vger.kernel.org Fixes: 35c8711c8fc4 ("io_uring/kbuf: add helpers for getting/peeking multiple buffers") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-28io_uring/kbuf: align legacy buffer add limit with MAX_BIDS_PER_BGIDliyouhong
io_provide_buffers_prep() accepts nbufs up to MAX_BIDS_PER_BGID, but io_add_buffers() stops when bl->nbufs reaches USHRT_MAX. This makes the effective add limit one lower than the validated limit. Use MAX_BIDS_PER_BGID in the add-side boundary check so validation and execution use the same limit, and update the comment to refer to the actual limit constant. Signed-off-by: liyouhong <liyouhong@kylinos.cn> Link: https://patch.msgid.link/20260528024936.3672659-1-dayou5941@163.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-05-14io_uring: parenthesize io_ring_head_to_buf() expansionYi Xie
Wrap the io_ring_head_to_buf() macro value in an extra pair of parentheses so it is safe when composed into larger expressions, and to satisfy scripts/checkpatch.pl. Signed-off-by: Yi Xie <xieyi@kylinos.cn> Link: https://patch.msgid.link/20260514083443.203387-1-xieyi@kylinos.cn Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-28io_uring/kbuf: support min length left for incremental buffersMartin Michaelis
Incrementally consumed buffer rings are generally fully consumed, but it's quite possible that the application has a minimum size it needs to meet to avoid truncation. Currently that minimum limit is 1 byte, but this should be a setting that is the hands of the application. For recvmsg multishot, a prime use case for incrementally consumed buffers, the application may get spurious -EFAULT returned at the end of an incrementally consumed buffer, as less space is available than the headers need. Grab a u32 field in struct io_uring_buf_reg, which the application can use to inform the kernel of the minimum size that should be available in an incrementally consumed buffer. If less than that is available, the current buffer is fully processed and the next one will be picked. Cc: stable@vger.kernel.org Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") Link: https://github.com/axboe/liburing/issues/1433 Signed-off-by: Martin Michaelis <code@mgjm.de> [axboe: write commit message, change io_buffer_list member name] Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-28io_uring/kbuf: kill dead struct io_buffer_list 'nr_entries' memberJens Axboe
This is only ever assigned, never used. The only used part is the calculated mask, which is used for indexing. Kill 'nr_entries'. Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-13Merge tag 'for-7.1/io_uring-20260411' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull io_uring updates from Jens Axboe: - Add a callback driven main loop for io_uring, and BPF struct_ops on top to allow implementing custom event loop logic - Decouple IOPOLL from being a ring-wide all-or-nothing setting, allowing IOPOLL use cases to also issue certain white listed non-polled opcodes - Timeout improvements. Migrate internal timeout storage from timespec64 to ktime_t for simpler arithmetic and avoid copying of timespec data - Zero-copy receive (zcrx) updates: - Add a device-less mode (ZCRX_REG_NODEV) for testing and experimentation where data flows through the copy fallback path - Fix two-step unregistration regression, DMA length calculations, xarray mark usage, and a potential 32-bit overflow in id shifting - Refactoring toward multi-area support: dedicated refill queue struct, consolidated DMA syncing, netmem array refilling format, and guard-based locking - Zero-copy transmit (zctx) cleanup: - Unify io_send_zc() and io_sendmsg_zc() into a single function - Add vectorized registered buffer send for IORING_OP_SEND_ZC - Add separate notification user_data via sqe->addr3 so notification and completion CQEs can be distinguished without extra reference counting - Switch struct io_ring_ctx internal bitfields to explicit flag bits with atomic-safe accessors, and annotate the known harmless races on those flags - Various optimizations caching ctx and other request fields in local variables to avoid repeated loads, and cleanups for tctx setup, ring fd registration, and read path early returns * tag 'for-7.1/io_uring-20260411' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (58 commits) io_uring: unify getting ctx from passed in file descriptor io_uring/register: don't get a reference to the registered ring fd io_uring/tctx: clean up __io_uring_add_tctx_node() error handling io_uring/tctx: have io_uring_alloc_task_context() return tctx io_uring/timeout: use 'ctx' consistently io_uring/rw: clean up __io_read() obsolete comment and early returns io_uring/zcrx: use correct mmap off constants io_uring/zcrx: use dma_len for chunk size calculation io_uring/zcrx: don't clear not allocated niovs io_uring/zcrx: don't use mark0 for allocating xarray io_uring: cast id to u64 before shifting in io_allocate_rbuf_ring() io_uring/zcrx: reject REG_NODEV with large rx_buf_size io_uring/cancel: validate opcode for IORING_ASYNC_CANCEL_OP io_uring/rsrc: use io_cache_free() to free node io_uring/zcrx: rename zcrx [un]register functions io_uring/zcrx: check ctrl op payload struct sizes io_uring/zcrx: cache fallback availability in zcrx ctx io_uring/zcrx: warn on a repeated area append io_uring/zcrx: consolidate dma syncing io_uring/zcrx: netmem array as refiling format ...
2026-03-20Merge tag 'io_uring-7.0-20260320' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull io_uring fixes from Jens Axboe: - A bit of a work-around for AF_UNIX recv multishot, as the in-kernel implementation doesn't properly signal EOF. We'll likely rework this one going forward, but the fix is sufficient for now - Two fixes for incrementally consumed buffers, for non-pollable files and for 0 byte reads * tag 'io_uring-7.0-20260320' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: io_uring/kbuf: propagate BUF_MORE through early buffer commit path io_uring/kbuf: fix missing BUF_MORE for incremental buffers at EOF io_uring/poll: fix multishot recv missing EOF on wakeup race
2026-03-19io_uring/kbuf: propagate BUF_MORE through early buffer commit pathJens Axboe
When io_should_commit() returns true (eg for non-pollable files), buffer commit happens at buffer selection time and sel->buf_list is set to NULL. When __io_put_kbufs() generates CQE flags at completion time, it calls __io_put_kbuf_ring() which finds a NULL buffer_list and hence cannot determine whether the buffer was consumed or not. This means that IORING_CQE_F_BUF_MORE is never set for non-pollable input with incrementally consumed buffers. Likewise for io_buffers_select(), which always commits upfront and discards the return value of io_kbuf_commit(). Add REQ_F_BUF_MORE to store the result of io_kbuf_commit() during early commit. Then __io_put_kbuf_ring() can check this flag and set IORING_F_BUF_MORE accordingy. Reported-by: Martin Michaelis <code@mgjm.de> Cc: stable@vger.kernel.org Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") Link: https://github.com/axboe/liburing/issues/1553 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-19io_uring/kbuf: fix missing BUF_MORE for incremental buffers at EOFJens Axboe
For a zero length transfer, io_kbuf_inc_commit() is called with !len. Since we never enter the while loop to consume the buffers, io_kbuf_inc_commit() ends up returning true, consuming the buffer. But if no data was consumed, by definition it cannot have consumed the buffer. Return false for that case. Reported-by: Martin Michaelis <code@mgjm.de> Cc: stable@vger.kernel.org Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") Link: https://github.com/axboe/liburing/issues/1553 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-17io_uring/kbuf: use 'ctx' consistentlyJens Axboe
There's already a local ctx variable, yet the ring lock and unlock helpers use req->ctx. use ctx consistently. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-03-14Merge branch 'io_uring-7.0' into for-7.1/io_uringJens Axboe
Merge upstream io_uring fixes to avoid conflicts in later patches. * io_uring-7.0: io_uring/kbuf: check if target buffer list is still legacy on recycle io_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops io_uring/eventfd: use ctx->rings_rcu for flags checking io_uring: ensure ctx->rings is stable for task work flags manipulation io_uring/bpf_filter: use bpf_prog_run_pin_on_cpu() to prevent migration io_uring/register: fix comment about task_no_new_privs
2026-03-13Merge tag 'io_uring-7.0-20260312' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull io_uring fixes from Jens Axboe: - Fix an inverted true/false comment on task_no_new_privs, from the BPF filtering changes merged in this release - Use the migration disabling way of running the BPF filters, as the io_uring side doesn't do that already - Fix an issue with ->rings stability under resize, both for local task_work additions and for eventfd signaling - Fix an issue with SQE mixed mode, where a bounds check wasn't correct for having a 128b SQE - Fix an issue where a legacy provided buffer group is changed to to ring mapped one while legacy buffers from that group are in flight * tag 'io_uring-7.0-20260312' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: io_uring/kbuf: check if target buffer list is still legacy on recycle io_uring: fix physical SQE bounds check for SQE_MIXED 128-byte ops io_uring/eventfd: use ctx->rings_rcu for flags checking io_uring: ensure ctx->rings is stable for task work flags manipulation io_uring/bpf_filter: use bpf_prog_run_pin_on_cpu() to prevent migration io_uring/register: fix comment about task_no_new_privs
2026-03-12io_uring/kbuf: check if target buffer list is still legacy on recycleJens Axboe
There's a gap between when the buffer was grabbed and when it potentially gets recycled, where if the list is empty, someone could've upgraded it to a ring provided type. This can happen if the request is forced via io-wq. The legacy recycling is missing checking if the buffer_list still exists, and if it's of the correct type. Add those checks. Cc: stable@vger.kernel.org Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") Reported-by: Keenan Dong <keenanat2000@gmail.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>
2026-02-21Merge tag 'kmalloc_obj-treewide-v7.0-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull kmalloc_obj conversion from Kees Cook: "This does the tree-wide conversion to kmalloc_obj() and friends using coccinelle, with a subsequent small manual cleanup of whitespace alignment that coccinelle does not handle. This uncovered a clang bug in __builtin_counted_by_ref(), so the conversion is preceded by disabling that for current versions of clang. The imminent clang 22.1 release has the fix. I've done allmodconfig build tests for x86_64, arm64, i386, and arm. I did defconfig builds for alpha, m68k, mips, parisc, powerpc, riscv, s390, sparc, sh, arc, csky, xtensa, hexagon, and openrisc" * tag 'kmalloc_obj-treewide-v7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: kmalloc_obj: Clean up after treewide replacements treewide: Replace kmalloc with kmalloc_obj for non-scalar types compiler_types: Disable __builtin_counted_by_ref for Clang
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>
2026-02-19io_uring: add IORING_OP_URING_CMD128 to opcode checksCaleb Sander Mateos
io_should_commit(), io_uring_classic_poll(), and io_do_iopoll() compare struct io_kiocb's opcode against IORING_OP_URING_CMD to implement special treatment for uring_cmds. The recently added opcode IORING_OP_URING_CMD128 is meant to be equivalent to IORING_OP_URING_CMD, so treat it the same way in these functions. Fixes: 1cba30bf9fdd ("io_uring: add support for IORING_SETUP_SQE_MIXED") Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Reviewed-by: Anuj Gupta <anuj20.g@samsung.com> Reviewed-by: Kanchan Joshi <joshi.k@samsung.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-02-05io_uring/kbuf: fix memory leak if io_buffer_add_list failsJens Axboe
io_register_pbuf_ring() ignores the return value of io_buffer_add_list(), which can fail if xa_store() returns an error (e.g., -ENOMEM). When this happens, the function returns 0 (success) to the caller, but the io_buffer_list structure is neither added to the xarray nor freed. In practice this requires failure injection to hit, hence not a real issue. But it should get fixed up none the less. Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-12-05io_uring/kbuf: use WRITE_ONCE() for userspace-shared buffer ring fieldsJoanne Koong
buf->addr and buf->len reside in memory shared with userspace. They should be written with WRITE_ONCE() to guarantee atomic stores and prevent tearing or other unsafe compiler optimizations. Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Cc: Caleb Sander Mateos <csander@purestorage.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-12-04io_uring/kbuf: use READ_ONCE() for userspace-mapped memoryCaleb Sander Mateos
The struct io_uring_buf elements in a buffer ring are in a memory region accessible from userspace. A malicious/buggy userspace program could therefore write to them at any time, so they should be accessed with READ_ONCE() in the kernel. Commit 98b6fa62c84f ("io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengths") already switched the reads of the len field to READ_ONCE(). Do the same for bid and addr. Signed-off-by: Caleb Sander Mateos <csander@purestorage.com> Fixes: c7fb19428d67 ("io_uring: add support for ring mapped supplied buffers") Cc: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-13Merge branch 'io_uring-6.18' into for-6.19/io_uringJens Axboe
Merge 6.18-rc io_uring fixes, as certain coming changes depend on some of these. * io_uring-6.18: io_uring/rsrc: don't use blk_rq_nr_phys_segments() as number of bvecs io_uring/query: return number of available queries io_uring/rw: ensure allocated iovec gets cleared for early failure io_uring: fix regbuf vector size truncation io_uring: fix types for region size calulation io_uring/zcrx: remove sync refill uapi io_uring: fix buffer auto-commit for multishot uring_cmd io_uring: correct __must_hold annotation in io_install_fixed_file io_uring zcrx: add MAINTAINERS entry io_uring: Fix code indentation error io_uring/sqpoll: be smarter on when to update the stime usage io_uring/sqpoll: switch away from getrusage() for CPU accounting io_uring: fix incorrect unlikely() usage in io_waitid_prep() Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-11-06io_uring/memmap: refactor io_free_region() to take user_struct paramDavid Wei
Refactor io_free_region() to take user_struct directly, instead of accessing it from the ring ctx. Signed-off-by: David Wei <dw@davidwei.uk> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-23io_uring: fix buffer auto-commit for multishot uring_cmdMing Lei
Commit 620a50c92700 ("io_uring: uring_cmd: add multishot support") added multishot uring_cmd support with explicit buffer upfront commit via io_uring_mshot_cmd_post_cqe(). However, the buffer selection path in io_ring_buffer_select() was auto-committing buffers for non-pollable files, which conflicts with uring_cmd's explicit upfront commit model. This way consumes the whole selected buffer immediately, and causes failure on the following buffer selection. Fix this by checking uring_cmd to identify operations that handle buffer commit explicitly, and skip auto-commit for these operations. Cc: Caleb Sander Mateos <csander@purestorage.com> Fixes: 620a50c92700 ("io_uring: uring_cmd: add multishot support") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-20io_uring/kbuf: use io_create_region for kbuf creationPavel Begunkov
kbuf ring is published by io_buffer_add_list(), which correctly protects with mmap_lock, there is no need to use io_create_region_mmap_safe() before as the region is not yet exposed to the userspace via mmap. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-02Merge tag 'for-6.18/io_uring-20250929' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux Pull io_uring updates from Jens Axboe: - Store ring provided buffers locally for the users, rather than stuff them into struct io_kiocb. These types of buffers must always be fully consumed or recycled in the current context, and leaving them in struct io_kiocb is hence not a good ideas as that struct has a vastly different life time. Basically just an architecture cleanup that can help prevent issues with ring provided buffers in the future. - Support for mixed CQE sizes in the same ring. Before this change, a CQ ring either used the default 16b CQEs, or it was setup with 32b CQE using IORING_SETUP_CQE32. For use cases where a few 32b CQEs were needed, this caused everything else to use big CQEs. This is wasteful both in terms of memory usage, but also memory bandwidth for the posted CQEs. With IORING_SETUP_CQE_MIXED, applications may use request types that post both normal 16b and big 32b CQEs on the same ring. - Add helpers for async data management, to make it harder for opcode handlers to mess it up. - Add support for multishot for uring_cmd, which ublk can use. This helps improve efficiency, by providing a persistent request type that can trigger multiple CQEs. - Add initial support for ring feature querying. We had basic support for probe operations, but the API isn't great. Rather than expand that, add support for QUERY which is easily expandable and can cover a lot more cases than the existing probe support. This will help applications get a better idea of what operations are supported on a given host. - zcrx improvements from Pavel: - Improve refill entry alignment for better caching - Various cleanups, especially around deduplicating normal memory vs dmabuf setup. - Generalisation of the niov size (Patch 12). It's still hard coded to PAGE_SIZE on init, but will let the user to specify the rx buffer length on setup. - Syscall / synchronous bufer return. It'll be used as a slow fallback path for returning buffers when the refill queue is full. Useful for tolerating slight queue size misconfiguration or with inconsistent load. - Accounting more memory to cgroups. - Additional independent cleanups that will also be useful for mutli-area support. - Various fixes and cleanups * tag 'for-6.18/io_uring-20250929' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (68 commits) io_uring/cmd: drop unused res2 param from io_uring_cmd_done() io_uring: fix nvme's 32b cqes on mixed cq io_uring/query: cap number of queries io_uring/query: prevent infinite loops io_uring/zcrx: account niov arrays to cgroup io_uring/zcrx: allow synchronous buffer return io_uring/zcrx: introduce io_parse_rqe() io_uring/zcrx: don't adjust free cache space io_uring/zcrx: use guards for the refill lock io_uring/zcrx: reduce netmem scope in refill io_uring/zcrx: protect netdev with pp_lock io_uring/zcrx: rename dma lock io_uring/zcrx: make niov size variable io_uring/zcrx: set sgt for umem area io_uring/zcrx: remove dmabuf_offset io_uring/zcrx: deduplicate area mapping io_uring/zcrx: pass ifq to io_zcrx_alloc_fallback() io_uring/zcrx: check all niovs filled with dma addresses io_uring/zcrx: move area reg checks into io_import_area io_uring/zcrx: don't pass slot to io_zcrx_create_area ...
2025-08-28io_uring/kbuf: always use READ_ONCE() to read ring provided buffer lengthsJens Axboe
Since the buffers are mapped from userspace, it is prudent to use READ_ONCE() to read the value into a local variable, and use that for any other actions taken. Having a stable read of the buffer length avoids worrying about it changing after checking, or being read multiple times. Similarly, the buffer may well change in between it being picked and being committed. Ensure the looping for incremental ring buffer commit stops if it hits a zero sized buffer, as no further progress can be made at that point. Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") Link: https://lore.kernel.org/io-uring/tencent_000C02641F6250C856D0C26228DE29A3D30A@qq.com/ Reported-by: Qingyue Zhang <chunzhennn@qq.com> Reported-by: Suoxing Zhang <aftern00n@qq.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-27io_uring/kbuf: fix signedness in this_len calculationQingyue Zhang
When importing and using buffers, buf->len is considered unsigned. However, buf->len is converted to signed int when committing. This can lead to unexpected behavior if the buffer is large enough to be interpreted as a negative value. Make min_t calculation unsigned. Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") Co-developed-by: Suoxing Zhang <aftern00n@qq.com> Signed-off-by: Suoxing Zhang <aftern00n@qq.com> Signed-off-by: Qingyue Zhang <chunzhennn@qq.com> Link: https://lore.kernel.org/r/tencent_4DBB3674C0419BEC2C0C525949DA410CA307@qq.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-24io_uring/kbuf: switch to storing struct io_buffer_list locallyJens Axboe
Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-24io_uring/kbuf: use struct io_br_sel for multiple buffers pickingJens Axboe
The networking side uses bundles, which is picking multiple buffers at the same time. Pass in struct io_br_sel to those helpers. Link: https://lore.kernel.org/r/20250821020750.598432-9-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-24io_uring/kbuf: introduce struct io_br_selJens Axboe
Rather than return addresses directly from buffer selection, add a struct around it. No functional changes in this patch, it's in preparation for storing more buffer related information locally, rather than in struct io_kiocb. Link: https://lore.kernel.org/r/20250821020750.598432-7-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-08-24io_uring/kbuf: pass in struct io_buffer_list to commit/recycle helpersJens Axboe
Rather than have this implied being in the io_kiocb, pass it in directly so it's immediately obvious where these users of ->buf_list are coming from. Link: https://lore.kernel.org/r/20250821020750.598432-6-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-06-26io_uring/kbuf: flag partial buffer mappingsJens Axboe
A previous commit aborted mapping more for a non-incremental ring for bundle peeking, but depending on where in the process this peeking happened, it would not necessarily prevent a retry by the user. That can create gaps in the received/read data. Add struct buf_sel_arg->partial_map, which can pass this information back. The networking side can then map that to internal state and use it to gate retry as well. Since this necessitates a new flag, change io_sr_msg->retry to a retry_flags member, and store both the retry and partial map condition in there. Cc: stable@vger.kernel.org Fixes: 26ec15e4b0c1 ("io_uring/kbuf: don't truncate end buffer for multiple buffer peeks") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-06-13io_uring/kbuf: don't truncate end buffer for multiple buffer peeksJens Axboe
If peeking a bunch of buffers, normally io_ring_buffers_peek() will truncate the end buffer. This isn't optimal as presumably more data will be arriving later, and hence it's better to stop with the last full buffer rather than truncate the end buffer. Cc: stable@vger.kernel.org Fixes: 35c8711c8fc4 ("io_uring/kbuf: add helpers for getting/peeking multiple buffers") Reported-by: Christian Mazakas <christian.mazakas@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-06-03io_uring/kbuf: limit legacy provided buffer lists to USHRT_MAXJens Axboe
The buffer ID for a provided buffer is an unsigned short, and hence there can only be 64k added to any given buffer list before having duplicate BIDs. Cap the legacy provided buffers at 64k in the list. This is mostly to prevent silly stall reports from syzbot, which likes to dump tons of buffers into a list and then have kernels with lockdep and kasan churning through them and hitting long wait times for buffer pruning at ring exit time. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-21io_uring: finish IOU_OK -> IOU_COMPLETE transitionJens Axboe
IOU_COMPLETE is more descriptive, in that it explicitly says that the return value means "please post a completion for this request". This patch completes the transition from IOU_OK to IOU_COMPLETE, replacing existing IOU_OK users. This is a purely mechanical change. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-13io_uring/kbuf: unify legacy buf provision and removalPavel Begunkov
Combine IORING_OP_PROVIDE_BUFFERS and IORING_OP_REMOVE_BUFFERS ->issue(), so that we can deduplicate ring locking and list lookups. This way we further reduce code for legacy provided buffers. Locking is also separated from buffer related handling, which makes it a bit simpler with label jumps. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/f61af131622ad4337c2fb9f7c453d5b0102c7b90.1747150490.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-13io_uring/kbuf: refactor __io_remove_buffersPavel Begunkov
__io_remove_buffers used for two purposes, the first is removing buffers for non ring based lists, which implies that it can be called multiple times for the same list. And the second is for destroying lists, which is not perfectly reentrable for ring based lists. It's confusing, so just have a helper for the legacy pbuf buffer removal, make sure it's not called for ring pbuf, and open code all ring pbuf destruction into io_put_bl(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/0ae416b099d311ad23f285cea02f2c94c8ae9a6c.1747150490.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-13io_uring/kbuf: don't compute size twice on prepPavel Begunkov
The size in prep is calculated by io_provide_buffers_prep(), so remove the recomputation a few lines after. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/7c97206561b74fce245cb22449c6082d2e066844.1747150490.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-13io_uring/kbuf: drop extra vars in io_register_pbuf_ringPavel Begunkov
bl and free_bl variables in io_register_pbuf_ring() always point to the same list since we started to reallocate the pre-existent list. Drop free_bl. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d45c3342d74c9030f99376c777a4b3d59089074d.1747150490.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-13io_uring/kbuf: use mem_is_zero()Pavel Begunkov
Make use of mem_is_zero() for reserved fields checking. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/11fe27b7a831329bcdb4ea087317ef123ba7c171.1747150490.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-13io_uring/kbuf: account ring io_buffer_list memoryPavel Begunkov
Follow the non-ringed pbuf struct io_buffer_list allocations and account it against the memcg. There is low chance of that being an actual problem as ring provided buffer should either pin user memory or allocate it, which is already accounted. Cc: stable@vger.kernel.org # 6.1 Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3985218b50d341273cafff7234e1a7e6d0db9808.1747150490.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-21io_uring: don't store bgid in req->buf_indexPavel Begunkov
Pass buffer group id into the rest of helpers via struct buf_sel_arg and remove all reassignments of req->buf_index back to bgid. Now, it only stores buffer indexes, and the group is provided by callers. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3ea9fa08113ecb4d9224b943e7806e80a324bdf9.1743437358.git.asml.silence@gmail.com Link: https://lore.kernel.org/io-uring/0c01d76ff12986c2f48614db8610caff8f78c869.1743500909.git.asml.silence@gmail.com/ [axboe: fold in patch from second link] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-21io_uring/kbuf: pass bgid to io_buffer_select()Pavel Begunkov
The current situation with buffer group id juggling is not ideal. req->buf_index first stores the bgid, then it's overwritten by a buffer id, and then it can get restored back no recycling / etc. It's not so easy to control, and it's not handled consistently across request types with receive requests saving and restoring the bgid it by hand. It's a prep patch that adds a buffer group id argument to io_buffer_select(). The caller will be responsible for stashing a copy somewhere and passing it into the function. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a210d6427cc3f4f42271a6853274cd5a50e56820.1743437358.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-07io_uring/kbuf: reject zero sized provided buffersJens Axboe
This isn't fixing a real issue, but there's also zero point in going through group and buffer setup, when the buffers are going to be rejected once attempted to get used. Cc: stable@vger.kernel.org Reported-by: syzbot+58928048fd1416f1457c@syzkaller.appspotmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-03-10io_uring/kbuf: enable bundles for incrementally consumed buffersJens Axboe
The original support for incrementally consumed buffers didn't allow it to be used with bundles, with the assumption being that incremental buffers are generally larger, and hence there's less of a nedd to support it. But that assumption may not be correct - it's perfectly viable to use smaller buffers with incremental consumption, and there may be valid reasons for an application or framework to do so. As there's really no need to explicitly disable bundles with incrementally consumed buffers, allow it. This actually makes the peek side cheaper and simpler, with the completion side basically the same, just needing to iterate for the consumed length. Reported-by: Norman Maurer <norman_maurer@apple.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-17io_uring/kbuf: uninline __io_put_kbufsPavel Begunkov
__io_put_kbufs() and other helper functions are too large to be inlined, compilers would normally refuse to do so. Uninline it and move together with io_kbuf_commit into kbuf.c. io_kbuf_commitSigned-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3dade7f55ad590e811aff83b1ec55c9c04e17b2b.1738724373.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-17io_uring/kbuf: introduce io_kbuf_drop_legacy()Pavel Begunkov
io_kbuf_drop() is only used for legacy provided buffers, and so __io_put_kbuf_list() is never called for REQ_F_BUFFER_RING. Remove the dead branch out of __io_put_kbuf_list(), rename it into io_kbuf_drop_legacy() and use it directly instead of io_kbuf_drop(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c8cc73e2272f09a86ecbdad9ebdd8304f8e583c0.1738724373.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-17io_uring/kbuf: open code __io_put_kbuf()Pavel Begunkov
__io_put_kbuf() is a trivial wrapper, open code it into __io_put_kbufs(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9dc17380272b48d56c95992c6f9eaacd5546e1d3.1738724373.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>