kernel/linux.git/io_uring/sqpoll.c, branch v7.0-rc7

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

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

io_uring: IOPOLL polling improvements

2025-12-28T22:54:45+00:00

io_uring manages issued and pending IOPOLL read/write requests in a singly linked list. One downside of that is that individual items cannot easily be removed from that list, and as a result, io_uring will only complete a completed request N in that list if 0..N-1 are also complete. For homogenous IO this isn't necessarily an issue, but if different devices are involved in polling in the same ring, or if disparate IO from the same device is being polled for, this can defer completion of some requests unnecessarily. Move to a doubly linked list for iopoll completions instead, making it possible to easily complete whatever requests that were polled done successfully. Co-developed-by: Fengnan Chang Link: https://lore.kernel.org/io-uring/20251210085501.84261-1-changfengnan@bytedance.com/ Signed-off-by: Jens Axboe

Merge branch 'io_uring-6.18' into for-6.19/io_uring

2025-11-13T14:26:37+00:00

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

io_uring/cancel: move cancelation code from io_uring.c to cancel.c

2025-11-04T16:32:09+00:00

There's a bunch of code strictly dealing with cancelations, and that code really belongs in cancel.c rather than in the core io_uring.c file. Move the code there. Mostly mechanical, only real oddity here is that struct io_defer_entry now needs to be visible across both io_uring.c and cancel.c. Signed-off-by: Jens Axboe

io_uring/sqpoll: be smarter on when to update the stime usage

2025-10-22T16:55:33+00:00

The current approach is a bit naive, and hence calls the time querying way too often. Only start the "doing work" timer when there's actual work to do, and then use that information to terminate (and account) the work time once done. This greatly reduces the frequency of these calls, when they cannot have changed anyway. Running a basic random reader that is setup to use SQPOLL, a profile before this change shows these as the top cycle consumers: + 32.60% iou-sqp-1074 [kernel.kallsyms] [k] thread_group_cputime_adjusted + 19.97% iou-sqp-1074 [kernel.kallsyms] [k] thread_group_cputime + 12.20% io_uring io_uring [.] submitter_uring_fn + 4.13% iou-sqp-1074 [kernel.kallsyms] [k] getrusage + 2.45% iou-sqp-1074 [kernel.kallsyms] [k] io_submit_sqes + 2.18% iou-sqp-1074 [kernel.kallsyms] [k] __pi_memset_generic + 2.09% iou-sqp-1074 [kernel.kallsyms] [k] cputime_adjust and after this change, top of profile looks as follows: + 36.23% io_uring io_uring [.] submitter_uring_fn + 23.26% iou-sqp-819 [kernel.kallsyms] [k] io_sq_thread + 10.14% iou-sqp-819 [kernel.kallsyms] [k] io_sq_tw + 6.52% iou-sqp-819 [kernel.kallsyms] [k] tctx_task_work_run + 4.82% iou-sqp-819 [kernel.kallsyms] [k] nvme_submit_cmds.part.0 + 2.91% iou-sqp-819 [kernel.kallsyms] [k] io_submit_sqes [...] 0.02% iou-sqp-819 [kernel.kallsyms] [k] cputime_adjust where it's spending the cycles on things that actually matter. Reported-by: Fengnan Chang Cc: stable@vger.kernel.org Fixes: 3fcb9d17206e ("io_uring/sqpoll: statistics of the true utilization of sq threads") Signed-off-by: Jens Axboe

io_uring/sqpoll: switch away from getrusage() for CPU accounting

2025-10-22T16:51:20+00:00

getrusage() does a lot more than what the SQPOLL accounting needs, the latter only cares about (and uses) the stime. Rather than do a full RUSAGE_SELF summation, just query the used stime instead. Cc: stable@vger.kernel.org Fixes: 3fcb9d17206e ("io_uring/sqpoll: statistics of the true utilization of sq threads") Reviewed-by: Gabriel Krisman Bertazi Signed-off-by: Jens Axboe

io_uring/sqpoll: don't put task_struct on tctx setup failure

2025-06-17T12:43:18+00:00

A recent commit moved the error handling of sqpoll thread and tctx failures into the thread itself, as part of fixing an issue. However, it missed that tctx allocation may also fail, and that io_sq_offload_create() does its own error handling for the task_struct in that case. Remove the manual task putting in io_sq_offload_create(), as io_sq_thread() will notice that the tctx did not get setup and hence it should put itself and exit. Reported-by: syzbot+763e12bbf004fb1062e4@syzkaller.appspotmail.com Fixes: ac0b8b327a56 ("io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()") Signed-off-by: Jens Axboe

io_uring: remove duplicate io_uring_alloc_task_context() definition

2025-06-17T12:41:48+00:00

This function exists in both tctx.h (where it belongs) and in io_uring.h as a remnant of before the tctx handling code got split out. Remove the io_uring.h definition and ensure that sqpoll.c includes the tctx.h header to get the definition. Signed-off-by: Jens Axboe

io_uring: consistently use rcu semantics with sqpoll thread

2025-06-12T14:17:09+00:00

The sqpoll thread is dereferenced with rcu read protection in one place, so it needs to be annotated as an __rcu type, and should consistently use rcu helpers for access and assignment to make sparse happy. Since most of the accesses occur under the sqd->lock, we can use rcu_dereference_protected() without declaring an rcu read section. Provide a simple helper to get the thread from a locked context. Fixes: ac0b8b327a5677d ("io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()") Signed-off-by: Keith Busch Link: https://lore.kernel.org/r/20250611205343.1821117-1-kbusch@meta.com [axboe: fold in fix for register.c] Signed-off-by: Jens Axboe