- 25 Jul, 2022 40 commits
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Dylan Yudaken authored
io_recvmsg_multishot_overflow had incorrect types on non x64 system. But also it had an unnecessary INT_MAX check, which could just be done by changing the type of the accumulator to int (also simplifying the casts). Reported-by:
Stephen Rothwell <sfr@canb.auug.org.au> Fixes: a8b38c4ce724 ("io_uring: support multishot in recvmsg") Signed-off-by:
Dylan Yudaken <dylany@fb.com> Link: https://lore.kernel.org/r/20220715130252.610639-1-dylany@fb.comSigned-off-by:
Jens Axboe <axboe@kernel.dk>
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Uros Bizjak authored
Use atomic_long_try_cmpxchg instead of atomic_long_cmpxchg (*ptr, old, new) == old in __io_account_mem. x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg (and related move instruction in front of cmpxchg). Also, atomic_long_try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg fails, enabling further code simplifications. No functional change intended. Signed-off-by:
Uros Bizjak <ubizjak@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by:
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Dylan Yudaken authored
Similar to multishot recv, this will require provided buffers to be used. However recvmsg is much more complex than recv as it has multiple outputs. Specifically flags, name, and control messages. Support this by introducing a new struct io_uring_recvmsg_out with 4 fields. namelen, controllen and flags match the similar out fields in msghdr from standard recvmsg(2), payloadlen is the length of the payload following the header. This struct is placed at the start of the returned buffer. Based on what the user specifies in struct msghdr, the next bytes of the buffer will be name (the next msg_namelen bytes), and then control (the next msg_controllen bytes). The payload will come at the end. The return value in the CQE is the total used size of the provided buffer. Signed-off-by:
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Dylan Yudaken authored
this is in preparation for multishot receive from io_uring, where it needs to have access to the original struct user_msghdr. functionally this should be a no-op. Acked-by:
Paolo Abeni <pabeni@redhat.com> Signed-off-by:
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Dylan Yudaken authored
this is in preparation for multishot receive from io_uring, where it needs to have access to the original struct user_msghdr. functionally this should be a no-op. Acked-by:
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Dylan Yudaken authored
Match up work done in "io_uring: allow iov_len = 0 for recvmsg and buffer select", but for compat code path. Fixes: a68caad69ce5 ("io_uring: allow iov_len = 0 for recvmsg and buffer select") Signed-off-by: -
Dylan Yudaken authored
If multishot is not actually polling then return IOU_OK rather than the result. If the result was > 0 this will confuse things further up the callstack which expect a return <= 0. Fixes: 1300ebb20286 ("io_uring: multishot recv") Signed-off-by: -
Jens Axboe authored
For recvmsg/sendmsg, if they don't complete inline, we currently need to allocate a struct io_async_msghdr for each request. This is a somewhat large struct. Hook up sendmsg/recvmsg to use the io_alloc_cache. This reduces the alloc + free overhead considerably, yielding 4-5% of extra performance running netbench. Signed-off-by: -
Jens Axboe authored
Caches like this tend to grow to the peak size, and then never get any smaller. Impose a max limit on the size, to prevent it from growing too big. A somewhat randomly chosen 512 is the max size we'll allow the cache to get. If a batch of frees come in and would bring it over that, we simply start kfree'ing the surplus. Signed-off-by: -
Jens Axboe authored
In preparation for adding limits, and one more user, abstract out the core bits of the allocation+free cache. Signed-off-by: -
Jens Axboe authored
This is where it's used, move the flush handler in there. Signed-off-by: -
Pavel Begunkov authored
Don't duplicate code disabling REQ_F_HASH_LOCKED for IO_URING_F_UNLOCKED (i.e. io-wq), move the handling into __io_arm_poll_handler(). Signed-off-by:
Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/0ff0ffdfaa65b3d536131535c3dad3c63d9b7bb0.1657203020.git.asml.silence@gmail.comSigned-off-by:
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Pavel Begunkov authored
Instead of clearing REQ_F_HASH_LOCKED while arming a poll, unset the bit when we're removing the entry from the table in io_poll_tw_hash_eject(). Signed-off-by:
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Pavel Begunkov authored
Just as with io_poll_double_prepare() setting REQ_F_DOUBLE_POLL, we can race with the first poll entry when setting REQ_F_ASYNC_DATA. Move it under io_poll_double_prepare(). Fixes: a18427bb2d9b ("io_uring: optimise submission side poll_refs") Signed-off-by: -
Pavel Begunkov authored
When adding a second poll entry we should set REQ_F_DOUBLE_POLL unconditionally. We might race with the first entry removal but that doesn't change the rule. Fixes: a18427bb2d9b ("io_uring: optimise submission side poll_refs") Reported-and-tested-by: syzbot+49950ba66096b1f0209b@syzkaller.appspotmail.com Signed-off-by: -
Dylan Yudaken authored
recvmsg has semantics that do not make it trivial to extend to multishot. Specifically it has user pointers and returns data in the original parameter. In order to make this API useful these will need to be somehow included with the provided buffers. For now remove multishot for recvmsg as it is not useful. Signed-off-by:
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Dylan Yudaken authored
In overflow we see a duplcate line in the trace, and in some cases 3 lines (if initial io_post_aux_cqe fails). Instead just trace once for each CQE Signed-off-by:
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Dylan Yudaken authored
Make the trace format consistent with io_uring_complete for cflags Signed-off-by:
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Dylan Yudaken authored
Support multishot receive for io_uring. Typical server applications will run a loop where for each recv CQE it requeues another recv/recvmsg. This can be simplified by using the existing multishot functionality combined with io_uring's provided buffers. The API is to add the IORING_RECV_MULTISHOT flag to the SQE. CQEs will then be posted (with IORING_CQE_F_MORE flag set) when data is available and is read. Once an error occurs or the socket ends, the multishot will be removed and a completion without IORING_CQE_F_MORE will be posted. The benefit to this is that the recv is much more performant. * Subsequent receives are queued up straight away without requiring the application to finish a processing loop. * If there are more data in the socket (sat the provided buffer size is smaller than the socket buffer) then the data is immediately returned, improving batching. * Poll is only armed once and reused, saving CPU cycles Signed-off-by:
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Dylan Yudaken authored
Similar to multishot poll, drop multishot accept when CQE overflow occurs. Signed-off-by:
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Dylan Yudaken authored
On overflow, multishot poll can still complete with the IORING_CQE_F_MORE flag set. If in the meantime the user clears a CQE and a the poll was cancelled then the poll will post a CQE without the IORING_CQE_F_MORE (and likely result -ECANCELED). However when processing the application will encounter the non-overflow CQE which indicates that there will be no more events posted. Typical userspace applications would free memory associated with the poll in this case. It will then subsequently receive the earlier CQE which has overflowed, which breaks the contract given by the IORING_CQE_F_MORE flag. Signed-off-by:
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Dylan Yudaken authored
Some use cases of io_post_aux_cqe would not want to overflow as is, but might want to change the flags/result. For example multishot receive requires in order CQE, and so if there is an overflow it would need to stop receiving until the overflow is taken care of. Signed-off-by:
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Dylan Yudaken authored
For multishot we want a way to signal the caller that multishot has ended but also this might not be an error return. For example sockets return 0 when closed, which should end a multishot recv, but still have a CQE with result 0 Introduce IOU_STOP_MULTISHOT which does this and indicates that the return code is stored inside req->cqe Signed-off-by:
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Dylan Yudaken authored
The values returned are a bit confusing, where 0 and 1 have implied meaning, so add some definitions for them. Signed-off-by:
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Dylan Yudaken authored
Rather than passing an error back to the user with a buffer attached, recycle the buffer immediately. Signed-off-by:
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Dylan Yudaken authored
When using BUFFER_SELECT there is no technical requirement that the user actually provides iov, and this removes one copy_from_user call. So allow iov_len to be 0. Signed-off-by:
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Dylan Yudaken authored
Attempt to restore bgid. This is needed when recycling unused buffers as the next time around it will want the correct bgid. Signed-off-by:
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Dylan Yudaken authored
If user gives 0 for length, we can set it from the available buffer size. Signed-off-by:
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Pavel Begunkov authored
From recently io_uring provides an option to allocate a file index for operation registering fixed files. However, it's utterly unusable with mixed approaches when for a part of files the userspace knows better where to place it, as it may race and users don't have any sane way to pick a slot and hoping it will not be taken. Let the userspace to register a range of fixed file slots in which the auto-allocation happens. The use case is splittting the fixed table in two parts, where on of them is used for auto-allocation and another for slot-specified operations. Signed-off-by:
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Jens Axboe authored
With IORING_OP_MSG_RING, one ring can send a message to another ring. Extend that support to also allow sending a fixed file descriptor to that ring, enabling one ring to pass a registered descriptor to another one. Arguments are extended to pass in: sqe->addr3 fixed file slot in source ring sqe->file_index fixed file slot in destination ring IORING_OP_MSG_RING is extended to take a command argument in sqe->addr. If set to zero (or IORING_MSG_DATA), it sends just a message like before. If set to IORING_MSG_SEND_FD, a fixed file descriptor is sent according to the above arguments. Two common use cases for this are: 1) Server needs to be shutdown or restarted, pass file descriptors to another onei 2) Backend is split, and one accepts connections, while others then get the fd passed and handle the actual connection. Both of those are classic SCM_RIGHTS use cases, and it's not possible to support them with direct descriptors today. By default, this will post a CQE to the target ring, similarly to how IORING_MSG_DATA does it. If IORING_MSG_RING_CQE_SKIP is set, no message is posted to the target ring. The issuer is expected to notify the receiver side separately. Signed-off-by: -
Jens Axboe authored
Put it with the filetable code, which is where it belongs. While doing so, have the helpers take a ctx rather than an io_kiocb. It doesn't make sense to use a request, as it's not an operation on the request itself. It applies to the ring itself. Signed-off-by: -
Gustavo A. R. Silva authored
There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/78Signed-off-by:
Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by:
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Pavel Begunkov authored
io_uring_enter() takes ctx->refs, which was previously preventing racing with register quiesce. However, as register now doesn't touch the refs, we can freely kill extra ctx pinning and rely on the fact that we're holding a file reference preventing the ring from being destroyed. Signed-off-by:
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Pavel Begunkov authored
Registered rings are per definitions io_uring files, so we don't need to additionally verify them. Signed-off-by:
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Pavel Begunkov authored
io_run_task_work() accounts for TIF_NOTIFY_SIGNAL, so no need to have an second check in io_run_task_work_sig(). Signed-off-by:
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Pavel Begunkov authored
Now as both normal and fallback paths use llist, just keep one node head in struct io_task_work and kill off ->fallback_node. Signed-off-by:
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Pavel Begunkov authored
io_fail_links() is called with ->completion_lock held and for that reason we'd want to keep it as small as we can. Instead of doing __io_req_complete_post() for each linked request under the lock, fail them in a task_work handler under ->uring_lock. Signed-off-by:
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Jens Axboe authored
We really don't care about this at all in terms of performance. Outside of having it already be marked unlikely(), shove it into a separate __cold function. Signed-off-by: -
Hao Xu authored
Make io_kbuf_recycle_ring() inline since it is the fast path of provided buffer. Signed-off-by:
Hao Xu <howeyxu@tencent.com> Link: https://lore.kernel.org/r/20220623130126.179232-1-hao.xu@linux.devSigned-off-by:
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Pavel Begunkov authored
The final poll_refs put in __io_arm_poll_handler() takes quite some cycles. When we're arming from the original task context task_work won't be run, so in this case we can assume that we won't race with task_works and so not take the initial ownership ref. One caveat is that after arming a poll we may race with it, so we have to add a bunch of io_poll_get_ownership() hidden inside of io_poll_can_finish_inline() whenever we want to complete arming inline. For the same reason we can't just set REQ_F_DOUBLE_POLL in __io_queue_proc() and so need to sync with the first poll entry by taking its wq head lock. Signed-off-by:
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