It can be useful to know if io_kbuf_recycle did actually recycle the
buffer on the request, or if it left the request alone.
Signed-off-by: Dylan Yudaken <dyudaken@gmail.com>
Link: https://lore.kernel.org/r/20231106203909.197089-2-dyudaken@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.7/io_uring-2023-10-30' of git://git.kernel.dk/linux
Pull io_uring updates from Jens Axboe:
"This contains the core io_uring updates, of which there are not many,
and adds support for using WAITID through io_uring and hence not
needing to block on these kinds of events.
Outside of that, tweaks to the legacy provided buffer handling and
some cleanups related to cancelations for uring_cmd support"
* tag 'for-6.7/io_uring-2023-10-30' of git://git.kernel.dk/linux:
io_uring/poll: use IOU_F_TWQ_LAZY_WAKE for wakeups
io_uring/kbuf: Use slab for struct io_buffer objects
io_uring/kbuf: Allow the full buffer id space for provided buffers
io_uring/kbuf: Fix check of BID wrapping in provided buffers
io_uring/rsrc: cleanup io_pin_pages()
io_uring: cancelable uring_cmd
io_uring: retain top 8bits of uring_cmd flags for kernel internal use
io_uring: add IORING_OP_WAITID support
exit: add internal include file with helpers
exit: add kernel_waitid_prepare() helper
exit: move core of do_wait() into helper
exit: abstract out should_wake helper for child_wait_callback()
io_uring/rw: add support for IORING_OP_READ_MULTISHOT
io_uring/rw: mark readv/writev as vectored in the opcode definition
io_uring/rw: split io_read() into a helper
The allocation of struct io_buffer for metadata of provided buffers is
done through a custom allocator that directly gets pages and
fragments them. But, slab would do just fine, as this is not a hot path
(in fact, it is a deprecated feature) and, by keeping a custom allocator
implementation we lose benefits like tracking, poisoning,
sanitizers. Finally, the custom code is more complex and requires
keeping the list of pages in struct ctx for no good reason. This patch
cleans this path up and just uses slab.
I microbenchmarked it by forcing the allocation of a large number of
objects with the least number of io_uring commands possible (keeping
nbufs=USHRT_MAX), with and without the patch. There is a slight
increase in time spent in the allocation with slab, of course, but even
when allocating to system resources exhaustion, which is not very
realistic and happened around 1/2 billion provided buffers for me, it
wasn't a significant hit in system time. Specially if we think of a
real-world scenario, an application doing register/unregister of
provided buffers will hit ctx->io_buffers_cache more often than actually
going to slab.
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20231005000531.30800-4-krisman@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
nbufs tracks the number of buffers and not the last bgid. In 16-bit, we
have 2^16 valid buffers, but the check mistakenly rejects the last
bid. Let's fix it to make the interface consistent with the
documentation.
Fixes: ddf0322db7 ("io_uring: add IORING_OP_PROVIDE_BUFFERS")
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20231005000531.30800-3-krisman@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 3851d25c75 ("io_uring: check for rollover of buffer ID when
providing buffers") introduced a check to prevent wrapping the BID
counter when sqe->off is provided, but it's off-by-one too
restrictive, rejecting the last possible BID (65534).
i.e., the following fails with -EINVAL.
io_uring_prep_provide_buffers(sqe, addr, size, 0xFFFF, 0, 0);
Fixes: 3851d25c75 ("io_uring: check for rollover of buffer ID when providing buffers")
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20231005000531.30800-2-krisman@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
syzbot reports that registering a mapped buffer ring on arm32 can
trigger an OOPS. Registered buffer rings have two modes, one of them
is the application passing in the memory that the buffer ring should
reside in. Once those pages are mapped, we use page_address() to get
a virtual address. This will obviously fail on highmem pages, which
aren't mapped.
Add a check if we have any highmem pages after mapping, and fail the
attempt to register a provided buffer ring if we do. This will return
the same error as kernels that don't support provided buffer rings to
begin with.
Link: https://lore.kernel.org/io-uring/000000000000af635c0606bcb889@google.com/
Fixes: c56e022c0a ("io_uring: add support for user mapped provided buffer ring")
Cc: stable@vger.kernel.org
Reported-by: syzbot+2113e61b8848fa7951d8@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Patch series "Remove _folio_dtor and _folio_order", v2.
This patch (of 13):
folio_put() is the standard way to write this, and it's not appreciably
slower. This is an enabling patch for removing free_compound_page()
entirely.
Link: https://lkml.kernel.org/r/20230816151201.3655946-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230816151201.3655946-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Merge tag 'for-6.4/io_uring-2023-04-21' of git://git.kernel.dk/linux
Pull io_uring updates from Jens Axboe:
- Cleanup of the io-wq per-node mapping, notably getting rid of it so
we just have a single io_wq entry per ring (Breno)
- Followup to the above, move accounting to io_wq as well and
completely drop struct io_wqe (Gabriel)
- Enable KASAN for the internal io_uring caches (Breno)
- Add support for multishot timeouts. Some applications use timeouts to
wake someone waiting on completion entries, and this makes it a bit
easier to just have a recurring timer rather than needing to rearm it
every time (David)
- Support archs that have shared cache coloring between userspace and
the kernel, and hence have strict address requirements for mmap'ing
the ring into userspace. This should only be parisc/hppa. (Helge, me)
- XFS has supported O_DIRECT writes without needing to lock the inode
exclusively for a long time, and ext4 now supports it as well. This
is true for the common cases of not extending the file size. Flag the
fs as having that feature, and utilize that to avoid serializing
those writes in io_uring (me)
- Enable completion batching for uring commands (me)
- Revert patch adding io_uring restriction to what can be GUP mapped or
not. This does not belong in io_uring, as io_uring isn't really
special in this regard. Since this is also getting in the way of
cleanups and improvements to the GUP code, get rid of if (me)
- A few series greatly reducing the complexity of registered resources,
like buffers or files. Not only does this clean up the code a lot,
the simplified code is also a LOT more efficient (Pavel)
- Series optimizing how we wait for events and run task_work related to
it (Pavel)
- Fixes for file/buffer unregistration with DEFER_TASKRUN (Pavel)
- Misc cleanups and improvements (Pavel, me)
* tag 'for-6.4/io_uring-2023-04-21' of git://git.kernel.dk/linux: (71 commits)
Revert "io_uring/rsrc: disallow multi-source reg buffers"
io_uring: add support for multishot timeouts
io_uring/rsrc: disassociate nodes and rsrc_data
io_uring/rsrc: devirtualise rsrc put callbacks
io_uring/rsrc: pass node to io_rsrc_put_work()
io_uring/rsrc: inline io_rsrc_put_work()
io_uring/rsrc: add empty flag in rsrc_node
io_uring/rsrc: merge nodes and io_rsrc_put
io_uring/rsrc: infer node from ctx on io_queue_rsrc_removal
io_uring/rsrc: remove unused io_rsrc_node::llist
io_uring/rsrc: refactor io_queue_rsrc_removal
io_uring/rsrc: simplify single file node switching
io_uring/rsrc: clean up __io_sqe_buffers_update()
io_uring/rsrc: inline switch_start fast path
io_uring/rsrc: remove rsrc_data refs
io_uring/rsrc: fix DEFER_TASKRUN rsrc quiesce
io_uring/rsrc: use wq for quiescing
io_uring/rsrc: refactor io_rsrc_ref_quiesce
io_uring/rsrc: remove io_rsrc_node::done
io_uring/rsrc: use nospec'ed indexes
...
The kernel test robot complains about __io_remove_buffers().
io_uring/kbuf.c:221 __io_remove_buffers() warn: variable dereferenced
before check 'bl->buf_ring' (see line 219)
That check is not needed as ->buf_ring will always be set, so we can
remove it and so silence the warning.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9a632bbf749d9d911e605255652ce08d18e7d2c6.1681210788.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
On at least parisc, we have strict requirements on how we virtually map
an address that is shared between the application and the kernel. On
these platforms, IOU_PBUF_RING_MMAP should be used when setting up a
shared ring buffer for provided buffers. If the application is mapping
these pages and asking the kernel to pin+map them as well, then we have
no control over what virtual address we get in the kernel.
For that case, do a sanity check if SHM_COLOUR is defined, and disallow
the mapping request. The application must fall back to using
IOU_PBUF_RING_MMAP for this case, and liburing will do that transparently
with the set of helpers that it has.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The ring mapped provided buffer rings rely on the application allocating
the memory for the ring, and then the kernel will map it. This generally
works fine, but runs into issues on some architectures where we need
to be able to ensure that the kernel and application virtual address for
the ring play nicely together. This at least impacts architectures that
set SHM_COLOUR, but potentially also anyone setting SHMLBA.
To use this variant of ring provided buffers, the application need not
allocate any memory for the ring. Instead the kernel will do so, and
the allocation must subsequently call mmap(2) on the ring with the
offset set to:
IORING_OFF_PBUF_RING | (bgid << IORING_OFF_PBUF_SHIFT)
to get a virtual address for the buffer ring. Normally the application
would allocate a suitable piece of memory (and correctly aligned) and
simply pass that in via io_uring_buf_reg.ring_addr and the kernel would
map it.
Outside of the setup differences, the kernel allocate + user mapped
provided buffer ring works exactly the same.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for allowing flags to be set for registration, rename
the padding and use it for that.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Rather than rely on checking buffer_list->buf_pages or ->buf_nr_pages,
add a separate member that tracks if this is a ring mapped provided
buffer list or not.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for allowing the kernel to allocate the provided buffer
rings and have the application mmap it instead, abstract out the
current method of pinning and mapping the user allocated ring.
No functional changes intended in this patch.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When removing provided buffers, io_buffer structs are not being disposed
of, leading to a memory leak. They can't be freed individually, because
they are allocated in page-sized groups. They need to be added to some
free list instead, such as io_buffers_cache. All callers already hold
the lock protecting it, apart from when destroying buffers, so had to
extend the lock there.
Fixes: cc3cec8367 ("io_uring: speedup provided buffer handling")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a request to remove buffers is submitted, and the given number to be
removed is larger than available in the specified buffer group, the
resulting CQE result will be the number of removed buffers + 1, which is
1 more than it should be.
Previously, the head was part of the list and it got removed after the
loop, so the increment was needed. Now, the head is not an element of
the list, so the increment shouldn't be there anymore.
Fixes: dbc7d452e7 ("io_uring: manage provided buffers strictly ordered")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Using struct_size() to calculate the size of io_uring_buf_ring will sum
the size of the struct and of the bufs array. However, the struct's fields
are overlaid with the array making the calculated size larger than it
should be.
When registering a ring with N * PAGE_SIZE / sizeof(struct io_uring_buf)
entries, i.e. with fully filled pages, the calculated size will span one
more page than it should and io_uring will try to pin the following page.
Depending on how the application allocated the ring, it might succeed
using an unrelated page or fail returning EFAULT.
The size of the ring should be the product of ring_entries and the size
of io_uring_buf, i.e. the size of the bufs array only.
Fixes: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20230218184141.70891-1-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now we're handling IOPOLL completions more generically, get rid uses of
_post() and send requests through the normal path. It may have some
extra mertis performance wise, but we don't care much as there is a
better interface for selected buffers.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4deded706587f55b006dc33adf0c13cfc3b2319f.1669310258.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We already check if the chosen starting offset for the buffer IDs fit
within an unsigned short, as 65535 is the maximum value for a provided
buffer. But if the caller asks to add N buffers at offset M, and M + N
would exceed the size of the unsigned short, we simply add buffers with
wrapping around the ID.
This is not necessarily a bug and could in fact be a valid use case, but
it seems confusing and inconsistent with the initial check for starting
offset. Let's check for wrap consistently, and error the addition if we
do need to wrap.
Reported-by: Olivier Langlois <olivier@trillion01.com>
Link: https://github.com/axboe/liburing/issues/726
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Potentially, someone may create as many pbuf bucket as there are indexes
in an xarray without any other restrictions bounding our memory usage,
put memory needed for the buckets under memory accounting.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d34c452e45793e978d26e2606211ec9070d329ea.1659622312.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_kbuf_recycle() is only called in io_kbuf_recycle(). Kill it and
tweak the code so that the legacy pbuf and ring pbuf code become clear
Signed-off-by: Hao Xu <howeyxu@tencent.com>
Link: https://lore.kernel.org/r/20220622055551.642370-1-hao.xu@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add comments to explain why it is always under uring lock when
incrementing head in __io_kbuf_recycle. And rectify one comemnt about
kbuf consuming in iowq case.
Signed-off-by: Hao Xu <howeyxu@tencent.com>
Link: https://lore.kernel.org/r/20220617050429.94293-1-hao.xu@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
