在 2026/6/22 13:28, Alexei Starovoitov 写道:
> On Sun, Jun 21, 2026 at 9:06 PM Kaitao Cheng <[email protected]> wrote:
>>
>> From: chengkaitao <[email protected]>
>>
>> The list_for_each*_safe() helpers are used when the loop body may remove
>> the current entry. Their current interface, however, forces every caller
>> to define a temporary cursor outside the macro and pass it in, even when
>> the caller never uses that cursor directly. For most call sites this
>> extra cursor is just boilerplate required by the macro implementation.
>>
>> This is awkward because the saved next pointer is an internal detail of
>> the iteration. Callers that only remove or move the current entry do not
>> need to spell it out.
>>
>> The _safe() suffix has also caused confusion. Christian Koenig pointed
>> out that the name is easy to read as a thread-safe variant, especially
>> for beginners, even though it only means that the iterator keeps enough
>> state to tolerate removal of the current entry. He suggested _mutable()
>> as a clearer description of what the loop permits.
>>
>> Add *_mutable() iterator variants for list, hlist and llist. The new
>> helpers are variadic and support both forms. In the common case, the
>> caller omits the temporary cursor and the macro creates a unique internal
>> cursor with typeof(pos) and __UNIQUE_ID(). If a loop really needs an
>> explicit temporary cursor, the caller can still pass it and the helper
>> keeps the existing *_safe() behaviour.
>>
>> For example, a call site may use the shorter form:
>>
>> list_for_each_entry_mutable(pos, head, member)
>>
>> or keep the explicit temporary cursor form:
>>
>> list_for_each_entry_mutable(pos, tmp, head, member)
>>
>> The existing *_safe() helpers remain available for compatibility. This
>> series only converts users in mm, block, kernel, init and io_uring. If
>> this approach looks acceptable, the remaining users can be converted in
>> follow-up series.
>>
>> Changes in v3 (Christian König, Andy Shevchenko):
>> - Convert safe list walks to mutable iterators
>>
>> Changes in v2 (Muchun Song, Andy Shevchenko):
>> - Drop the list_for_each_entry_mutable*() helpers from v1 and make the
>> cursor change directly in the existing list_for_each_entry*() helpers.
>> - Open-code special list walks that rely on updating the loop cursor in
>> the body, preserving their existing traversal semantics.
>>
>> Link to v2:
>> https://lore.kernel.org/all/[email protected]/
>>
>> Link to v1:
>> https://lore.kernel.org/all/[email protected]/
>>
>> Kaitao Cheng (7):
>> list: Add mutable iterator variants
>> llist: Add mutable iterator variants
>> mm: Use mutable list iterators
>> block: Use mutable list iterators
>> kernel: Use mutable list iterators
>> initramfs: Use mutable list iterator
>> io_uring: Use mutable list iterators
>>
>> block/bfq-iosched.c | 17 +-
>> block/blk-cgroup.c | 12 +-
>> block/blk-flush.c | 4 +-
>> block/blk-iocost.c | 18 +-
>> block/blk-mq.c | 8 +-
>> block/blk-throttle.c | 4 +-
>> block/kyber-iosched.c | 4 +-
>> block/partitions/ldm.c | 8 +-
>> block/sed-opal.c | 4 +-
>> include/linux/list.h | 269 ++++++++++++++++++++++++----
>> include/linux/llist.h | 81 +++++++--
>> init/initramfs.c | 5 +-
>> io_uring/cancel.c | 6 +-
>> io_uring/poll.c | 3 +-
>> io_uring/rw.c | 4 +-
>> io_uring/timeout.c | 8 +-
>> io_uring/uring_cmd.c | 3 +-
>> kernel/audit_tree.c | 4 +-
>> kernel/audit_watch.c | 16 +-
>> kernel/auditfilter.c | 4 +-
>> kernel/auditsc.c | 4 +-
>> kernel/bpf/arena.c | 10 +-
>> kernel/bpf/arraymap.c | 8 +-
>> kernel/bpf/bpf_local_storage.c | 3 +-
>> kernel/bpf/bpf_lru_list.c | 25 ++-
>> kernel/bpf/btf.c | 18 +-
>> kernel/bpf/cgroup.c | 7 +-
>> kernel/bpf/cpumap.c | 4 +-
>> kernel/bpf/devmap.c | 10 +-
>> kernel/bpf/helpers.c | 8 +-
>> kernel/bpf/local_storage.c | 4 +-
>> kernel/bpf/memalloc.c | 16 +-
>> kernel/bpf/offload.c | 8 +-
>> kernel/bpf/states.c | 4 +-
>> kernel/bpf/stream.c | 4 +-
>> kernel/bpf/verifier.c | 6 +-
>> kernel/cgroup/cgroup-v1.c | 4 +-
>> kernel/cgroup/cgroup.c | 54 +++---
>> kernel/cgroup/dmem.c | 12 +-
>> kernel/cgroup/rdma.c | 8 +-
>> kernel/events/core.c | 44 +++--
>> kernel/events/uprobes.c | 12 +-
>> kernel/exit.c | 8 +-
>> kernel/fail_function.c | 4 +-
>> kernel/gcov/clang.c | 4 +-
>> kernel/irq_work.c | 4 +-
>> kernel/kexec_core.c | 4 +-
>> kernel/kprobes.c | 16 +-
>> kernel/livepatch/core.c | 4 +-
>> kernel/livepatch/core.h | 4 +-
>> kernel/liveupdate/kho_block.c | 4 +-
>> kernel/liveupdate/luo_flb.c | 4 +-
>> kernel/locking/rwsem.c | 2 +-
>> kernel/locking/test-ww_mutex.c | 2 +-
>> kernel/module/main.c | 11 +-
>> kernel/padata.c | 4 +-
>> kernel/power/snapshot.c | 8 +-
>> kernel/power/wakelock.c | 4 +-
>> kernel/printk/printk.c | 11 +-
>> kernel/ptrace.c | 4 +-
>> kernel/rcu/rcutorture.c | 3 +-
>> kernel/rcu/tasks.h | 9 +-
>> kernel/rcu/tree.c | 6 +-
>> kernel/resource.c | 4 +-
>> kernel/sched/core.c | 4 +-
>> kernel/sched/ext.c | 22 +--
>> kernel/sched/fair.c | 28 +--
>> kernel/sched/topology.c | 4 +-
>> kernel/sched/wait.c | 4 +-
>> kernel/seccomp.c | 4 +-
>> kernel/signal.c | 11 +-
>> kernel/smp.c | 4 +-
>> kernel/taskstats.c | 8 +-
>> kernel/time/clockevents.c | 6 +-
>> kernel/time/clocksource.c | 4 +-
>> kernel/time/posix-cpu-timers.c | 4 +-
>> kernel/time/posix-timers.c | 3 +-
>> kernel/torture.c | 3 +-
>> kernel/trace/bpf_trace.c | 4 +-
>> kernel/trace/ftrace.c | 49 +++--
>> kernel/trace/ring_buffer.c | 25 ++-
>> kernel/trace/trace.c | 12 +-
>> kernel/trace/trace_dynevent.c | 6 +-
>> kernel/trace/trace_dynevent.h | 5 +-
>> kernel/trace/trace_events.c | 35 ++--
>> kernel/trace/trace_events_filter.c | 4 +-
>> kernel/trace/trace_events_hist.c | 8 +-
>> kernel/trace/trace_events_trigger.c | 17 +-
>> kernel/trace/trace_events_user.c | 16 +-
>> kernel/trace/trace_stat.c | 4 +-
>> kernel/user-return-notifier.c | 3 +-
>> kernel/workqueue.c | 16 +-
>> mm/backing-dev.c | 8 +-
>> mm/balloon.c | 8 +-
>> mm/cma.c | 4 +-
>> mm/compaction.c | 4 +-
>> mm/damon/core.c | 4 +-
>> mm/damon/sysfs-schemes.c | 4 +-
>> mm/dmapool.c | 4 +-
>> mm/huge_memory.c | 8 +-
>> mm/hugetlb.c | 56 +++---
>> mm/hugetlb_vmemmap.c | 16 +-
>> mm/khugepaged.c | 14 +-
>> mm/kmemleak.c | 7 +-
>> mm/ksm.c | 25 +--
>> mm/list_lru.c | 4 +-
>> mm/memcontrol-v1.c | 8 +-
>> mm/memory-failure.c | 12 +-
>> mm/memory-tiers.c | 4 +-
>> mm/migrate.c | 23 ++-
>> mm/mmu_notifier.c | 9 +-
>> mm/page_alloc.c | 8 +-
>> mm/page_reporting.c | 2 +-
>> mm/percpu.c | 11 +-
>> mm/pgtable-generic.c | 4 +-
>> mm/rmap.c | 10 +-
>> mm/shmem.c | 9 +-
>> mm/slab_common.c | 14 +-
>> mm/slub.c | 33 ++--
>> mm/swapfile.c | 4 +-
>> mm/userfaultfd.c | 12 +-
>> mm/vmalloc.c | 24 +--
>> mm/vmscan.c | 7 +-
>> mm/zsmalloc.c | 4 +-
>> 124 files changed, 875 insertions(+), 681 deletions(-)
>
> Not sure what you were thinking, but this diff stat
> is not landable.
[PATCH v3 1/7] and [PATCH v3 2/7] contain the main logic and can
be merged directly. They are also compatible with the old API.
[PATCH v3 3/7] through [PATCH v3 7/7] are just simple interface
replacements and do not change any functional logic. They can be
left unmerged for now; individual modules can pick them up later
if needed.
In v2, Andy Shevchenko mentioned: "If it's done by Linus himself
during the day when he prepares -rc1, it's fine." Even so, the
changes in this patch series are indeed quite large and touch
almost every subsystem. I have only converted part of them for
now, so I wanted to send this out first and see what people think.
--
Thanks
Kaitao Cheng
