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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>
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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>
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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>
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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>
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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>
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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>
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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
...
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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__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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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__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>
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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>
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__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>
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Remove all struct io_buffer caches. It makes it a fair bit simpler.
Apart from from killing a bunch of lines and juggling between lists,
__io_put_kbuf_list() doesn't need ->completion_lock locking now.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/18287217466ee2576ea0b1e72daccf7b22c7e856.1738724373.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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As a preparation step remove an optimisation from __io_put_kbuf() trying
to use the locked cache. With that __io_put_kbuf_list() is only used
with ->io_buffers_comp, and we remove the explicit list argument.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1b7f1394ec4afc7f96b35a61f5992e27c49fd067.1738724373.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Remove the kmem cache used by legacy provided buffers.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8195c207d8524d94e972c0c82de99282289f7f5c.1738724373.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Legacy provided buffers are slow and discouraged in favour of the ring
variant. Remove the bulk allocation to keep it simpler as we don't care
about performance.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a064d70370e590efed8076e9501ae4cfc20fe0ca.1738724373.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it
was created for legacy selected buffer and has been emptied. It violates
the requirement that most of the field should stay stable after publish.
Always reallocate it instead.
Cc: stable@vger.kernel.org
Reported-by: Pumpkin Chang <pumpkin@devco.re>
Fixes: 2fcabce2d7d34 ("io_uring: disallow mixed provided buffer group registrations")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull io_uring updates from Jens Axboe:
"Not a lot in terms of features this time around, mostly just cleanups
and code consolidation:
- Support for PI meta data read/write via io_uring, with NVMe and
SCSI covered
- Cleanup the per-op structure caching, making it consistent across
various command types
- Consolidate the various user mapped features into a concept called
regions, making the various users of that consistent
- Various cleanups and fixes"
* tag 'for-6.14/io_uring-20250119' of git://git.kernel.dk/linux: (56 commits)
io_uring/fdinfo: fix io_uring_show_fdinfo() misuse of ->d_iname
io_uring: reuse io_should_terminate_tw() for cmds
io_uring: Factor out a function to parse restrictions
io_uring/rsrc: require cloned buffers to share accounting contexts
io_uring: simplify the SQPOLL thread check when cancelling requests
io_uring: expose read/write attribute capability
io_uring/rw: don't gate retry on completion context
io_uring/rw: handle -EAGAIN retry at IO completion time
io_uring/rw: use io_rw_recycle() from cleanup path
io_uring/rsrc: simplify the bvec iter count calculation
io_uring: ensure io_queue_deferred() is out-of-line
io_uring/rw: always clear ->bytes_done on io_async_rw setup
io_uring/rw: use NULL for rw->free_iovec assigment
io_uring/rw: don't mask in f_iocb_flags
io_uring/msg_ring: Drop custom destructor
io_uring: Move old async data allocation helper to header
io_uring/rw: Allocate async data through helper
io_uring/net: Allocate msghdr async data through helper
io_uring/uring_cmd: Allocate async data through generic helper
io_uring/poll: Allocate apoll with generic alloc_cache helper
...
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For non-pollable files, buffer ring consumption will commit upfront.
This is fine, but io_ring_buffer_select() will return the address of the
buffer after having committed it. For incrementally consumed buffers,
this is incorrect as it will modify the buffer address.
Store the pre-committed value and return that. If that isn't done, then
the initial part of the buffer is not used and the application will
correctly assume the content arrived at the start of the userspace
buffer, but the kernel will have put it later in the buffer. Or it can
cause a spurious -EFAULT returned in the CQE, depending on the buffer
size. As bounds are suitably checked for doing the actual IO, no adverse
side effects are possible - it's just a data misplacement within the
existing buffer.
Reported-by: Gwendal Fernet <gwendalfernet@gmail.com>
Cc: stable@vger.kernel.org
Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Shifting reg.bgid << IORING_OFF_PBUF_SHIFT results in a promotion
from __u16 to a 32 bit signed integer, this is then sign extended
to a 64 bit unsigned long on 64 bit architectures. If reg.bgid is
greater than 0x7fff then this leads to a sign extended result where
all the upper 32 bits of mmap_offset are set to 1. Fix this by
casting reg.bgid to the same type as mmap_offset before performing
the shift.
Fixes: ef62de3c4ad5 ("io_uring/kbuf: use region api for pbuf rings")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20241204153923.401674-1-colin.i.king@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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All mapped memory is now backed by regions and we can unify and clean
up io_region_validate_mmap() and io_uring_mmap(). Extract a function
looking up a region, the rest of the handling should be generic and just
needs the region.
There is one more ring type specific code, i.e. the mmaping size
truncation quirk for IORING_OFF_[S,C]Q_RING, which is left as is.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f5e1eda1562bfd34276de07465525ae5f10e1e84.1732886067.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Convert internal parts of the provided buffer ring managment to the
region API. It's the last non-region mapped ring we have, so it also
kills a bunch of now unused memmap.c helpers.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6c40cf7beaa648558acd4d84bc0fb3279a35d74b.1732886067.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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struct io_buffer_list refcounting was needed for RCU based sync with
mmap, now we can kill it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4a9cc54bf0077bb2bf2f3daf917549ddd41080da.1732886067.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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A preparation / cleanup patch simplifying the buf ring - mmap
synchronisation. Instead of relying on RCU, which is trickier, do it by
grabbing the mmap_lock when when anyone tries to publish or remove a
registered buffer to / from ->io_bl_xa.
Modifications of the xarray should always be protected by both
->uring_lock and ->mmap_lock, while lookups should hold either of them.
While a struct io_buffer_list is in the xarray, the mmap related fields
like ->flags and ->buf_pages should stay stable.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/af13bde56ee1a26bcaefaa9aad37a9ea318a590e.1732886067.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull io_uring updates from Jens Axboe:
- NAPI fixes and cleanups (Pavel, Olivier)
- Add support for absolute timeouts (Pavel)
- Fixes for io-wq/sqpoll affinities (Felix)
- Efficiency improvements for dealing with huge pages (Chenliang)
- Support for a minwait mode, where the application essentially has two
timouts - one smaller one that defines the batch timeout, and the
overall large one similar to what we had before. This enables
efficient use of batching based on count + timeout, while still
working well with periods of less intensive workloads
- Use ITER_UBUF for single segment sends
- Add support for incremental buffer consumption. Right now each
operation will always consume a full buffer. With incremental
consumption, a recv/read operation only consumes the part of the
buffer that it needs to satisfy the operation
- Add support for GCOV for io_uring, to help retain a high coverage of
test to code ratio
- Fix regression with ocfs2, where an odd -EOPNOTSUPP wasn't correctly
converted to a blocking retry
- Add support for cloning registered buffers from one ring to another
- Misc cleanups (Anuj, me)
* tag 'for-6.12/io_uring-20240913' of git://git.kernel.dk/linux: (35 commits)
io_uring: add IORING_REGISTER_COPY_BUFFERS method
io_uring/register: provide helper to get io_ring_ctx from 'fd'
io_uring/rsrc: add reference count to struct io_mapped_ubuf
io_uring/rsrc: clear 'slot' entry upfront
io_uring/io-wq: inherit cpuset of cgroup in io worker
io_uring/io-wq: do not allow pinning outside of cpuset
io_uring/rw: drop -EOPNOTSUPP check in __io_complete_rw_common()
io_uring/rw: treat -EOPNOTSUPP for IOCB_NOWAIT like -EAGAIN
io_uring/sqpoll: do not allow pinning outside of cpuset
io_uring/eventfd: move refs to refcount_t
io_uring: remove unused rsrc_put_fn
io_uring: add new line after variable declaration
io_uring: add GCOV_PROFILE_URING Kconfig option
io_uring/kbuf: add support for incremental buffer consumption
io_uring/kbuf: pass in 'len' argument for buffer commit
Revert "io_uring: Require zeroed sqe->len on provided-buffers send"
io_uring/kbuf: move io_ring_head_to_buf() to kbuf.h
io_uring/kbuf: add io_kbuf_commit() helper
io_uring/kbuf: shrink nr_iovs/mode in struct buf_sel_arg
io_uring: wire up min batch wake timeout
...
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io_provided_buffers_select() returns 0 to indicate success, but it should
be returning 1 to indicate that 1 vec was mapped. This causes peeking
to fail with classic provided buffers, and while that's not a use case
that anyone should use, it should still work correctly.
The end result is that no buffer will be selected, and hence a completion
with '0' as the result will be posted, without a buffer attached.
Fixes: 35c8711c8fc4 ("io_uring/kbuf: add helpers for getting/peeking multiple buffers")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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By default, any recv/read operation that uses provided buffers will
consume at least 1 buffer fully (and maybe more, in case of bundles).
This adds support for incremental consumption, meaning that an
application may add large buffers, and each read/recv will just consume
the part of the buffer that it needs.
For example, let's say an application registers 1MB buffers in a
provided buffer ring, for streaming receives. If it gets a short recv,
then the full 1MB buffer will be consumed and passed back to the
application. With incremental consumption, only the part that was
actually used is consumed, and the buffer remains the current one.
This means that both the application and the kernel needs to keep track
of what the current receive point is. Each recv will still pass back a
buffer ID and the size consumed, the only difference is that before the
next receive would always be the next buffer in the ring. Now the same
buffer ID may return multiple receives, each at an offset into that
buffer from where the previous receive left off. Example:
Application registers a provided buffer ring, and adds two 32K buffers
to the ring.
Buffer1 address: 0x1000000 (buffer ID 0)
Buffer2 address: 0x2000000 (buffer ID 1)
A recv completion is received with the following values:
cqe->res 0x1000 (4k bytes received)
cqe->flags 0x11 (CQE_F_BUFFER|CQE_F_BUF_MORE set, buffer ID 0)
and the application now knows that 4096b of data is available at
0x1000000, the start of that buffer, and that more data from this buffer
will be coming. Now the next receive comes in:
cqe->res 0x2010 (8k bytes received)
cqe->flags 0x11 (CQE_F_BUFFER|CQE_F_BUF_MORE set, buffer ID 0)
which tells the application that 8k is available where the last
completion left off, at 0x1001000. Next completion is:
cqe->res 0x5000 (20k bytes received)
cqe->flags 0x1 (CQE_F_BUFFER set, buffer ID 0)
and the application now knows that 20k of data is available at
0x1003000, which is where the previous receive ended. CQE_F_BUF_MORE
isn't set, as no more data is available in this buffer ID. The next
completion is then:
cqe->res 0x1000 (4k bytes received)
cqe->flags 0x10001 (CQE_F_BUFFER|CQE_F_BUF_MORE set, buffer ID 1)
which tells the application that buffer ID 1 is now the current one,
hence there's 4k of valid data at 0x2000000. 0x2001000 will be the next
receive point for this buffer ID.
When a buffer will be reused by future CQE completions,
IORING_CQE_BUF_MORE will be set in cqe->flags. This tells the application
that the kernel isn't done with the buffer yet, and that it should expect
more completions for this buffer ID. Will only be set by provided buffer
rings setup with IOU_PBUF_RING INC, as that's the only type of buffer
that will see multiple consecutive completions for the same buffer ID.
For any other provided buffer type, any completion that passes back
a buffer to the application is final.
Once a buffer has been fully consumed, the buffer ring head is
incremented and the next receive will indicate the next buffer ID in the
CQE cflags.
On the send side, the application can manage how much data is sent from
an existing buffer by setting sqe->len to the desired send length.
An application can request incremental consumption by setting
IOU_PBUF_RING_INC in the provided buffer ring registration. Outside of
that, any provided buffer ring setup and buffer additions is done like
before, no changes there. The only change is in how an application may
see multiple completions for the same buffer ID, hence needing to know
where the next receive will happen.
Note that like existing provided buffer rings, this should not be used
with IOSQE_ASYNC, as both really require the ring to remain locked over
the duration of the buffer selection and the operation completion. It
will consume a buffer otherwise regardless of the size of the IO done.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In preparation for needing the consumed length, pass in the length being
completed. Unused right now, but will be used when it is possible to
partially consume a buffer.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In preparation for using this helper in kbuf.h as well, move it there and
turn it into a macro.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Committing the selected ring buffer is currently done in three different
spots, combine it into a helper and just call that.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We could just move these two and save some space, but in preparation
for adding another flag, turn them into flags first.
This saves 8 bytes in struct io_buffer_list, making it exactly half
a cacheline on 64-bit archs now rather than 40 bytes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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req->buf_list is assigned higher up and is safe to use as we remain
within a locked region, as is the 'bl' variable itself from which it
was assigned. To improve readability, use 'bl' directly rather than
get it from the io_kiocb, if we need to increment the head directly
in the buffer selection path. This makes it readily apparent that
it's the same io_buffer_list being used.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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