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2024-05-07io_uring/io-wq: Use set_bit() and test_bit() at worker->flagsBreno Leitao
Utilize set_bit() and test_bit() on worker->flags within io_uring/io-wq to address potential data races. The structure io_worker->flags may be accessed through various data paths, leading to concurrency issues. When KCSAN is enabled, it reveals data races occurring in io_worker_handle_work and io_wq_activate_free_worker functions. BUG: KCSAN: data-race in io_worker_handle_work / io_wq_activate_free_worker write to 0xffff8885c4246404 of 4 bytes by task 49071 on cpu 28: io_worker_handle_work (io_uring/io-wq.c:434 io_uring/io-wq.c:569) io_wq_worker (io_uring/io-wq.c:?) <snip> read to 0xffff8885c4246404 of 4 bytes by task 49024 on cpu 5: io_wq_activate_free_worker (io_uring/io-wq.c:? io_uring/io-wq.c:285) io_wq_enqueue (io_uring/io-wq.c:947) io_queue_iowq (io_uring/io_uring.c:524) io_req_task_submit (io_uring/io_uring.c:1511) io_handle_tw_list (io_uring/io_uring.c:1198) <snip> Line numbers against commit 18daea77cca6 ("Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm"). These races involve writes and reads to the same memory location by different tasks running on different CPUs. To mitigate this, refactor the code to use atomic operations such as set_bit(), test_bit(), and clear_bit() instead of basic "and" and "or" operations. This ensures thread-safe manipulation of worker flags. Also, move `create_index` to avoid holes in the structure. Signed-off-by: Breno Leitao <leitao@debian.org> Link: https://lore.kernel.org/r/20240507170002.2269003-1-leitao@debian.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-01io_uring/msg_ring: cleanup posting to IOPOLL vs !IOPOLL ringJens Axboe
Move the posting outside the checking and locking, it's cleaner that way. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-01io_uring: Require zeroed sqe->len on provided-buffers sendGabriel Krisman Bertazi
When sending from a provided buffer, we set sr->len to be the smallest between the actual buffer size and sqe->len. But, now that we disconnect the buffer from the submission request, we can get in a situation where the buffers and requests mismatch, and only part of a buffer gets sent. Assume: * buf[1]->len = 128; buf[2]->len = 256 * sqe[1]->len = 128; sqe[2]->len = 256 If sqe1 runs first, it picks buff[1] and it's all good. But, if sqe[2] runs first, sqe[1] picks buff[2], and the last half of buff[2] is never sent. While arguably the use-case of different-length sends is questionable, it has already raised confusion with potential users of this feature. Let's make the interface less tricky by forcing the length to only come from the buffer ring entry itself. Fixes: ac5f71a3d9d7 ("io_uring/net: add provided buffer support for IORING_OP_SEND") Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-30io_uring/notif: disable LAZY_WAKE for linked notifsPavel Begunkov
Notifications may now be linked and thus a single tw can post multiple CQEs, it's not safe to use LAZY_WAKE with them. Disable LAZY_WAKE for now, if that'd prove to be a problem we can count them and pass the expected number of CQEs into __io_req_task_work_add(). Fixes: 6fe4220912d19 ("io_uring/notif: implement notification stacking") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/0a5accdb7d2d0d27ebec14f8106e14e0192fae17.1714488419.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-30io_uring/net: fix sendzc lazy wake pollingPavel Begunkov
SEND[MSG]_ZC produces multiple CQEs via notifications, LAZY_WAKE doesn't handle it and so disable LAZY_WAKE for sendzc polling. It should be fine, sends are not likely to be polled in the first place. Fixes: 6ce4a93dbb5b ("io_uring/poll: use IOU_F_TWQ_LAZY_WAKE for wakeups") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/5b360fb352d91e3aec751d75c87dfb4753a084ee.1714488419.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-26io_uring/msg_ring: reuse ctx->submitter_task read using READ_ONCE instead of ↵linke li
re-reading it In io_msg_exec_remote(), ctx->submitter_task is read using READ_ONCE at the beginning of the function, checked, and then re-read from ctx->submitter_task, voiding all guarantees of the checks. Reuse the value that was read by READ_ONCE to ensure the consistency of the task struct throughout the function. Signed-off-by: linke li <lilinke99@qq.com> Link: https://lore.kernel.org/r/tencent_F9B2296C93928D6F68FF0C95C33475C68209@qq.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-25io_uring/rw: reinstate thread check for retriesJens Axboe
Allowing retries for everything is arguably the right thing to do, now that every command type is async read from the start. But it's exposed a few issues around missing check for a retry (which cca6571381a0 exposed), and the fixup commit for that isn't necessarily 100% sound in terms of iov_iter state. For now, just revert these two commits. This unfortunately then re-opens the fact that -EAGAIN can get bubbled to userspace for some cases where the kernel very well could just sanely retry them. But until we have all the conditions covered around that, we cannot safely enable that. This reverts commit df604d2ad480fcf7b39767280c9093e13b1de952. This reverts commit cca6571381a0bdc88021a1f7a4c2349df21279f7. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22io_uring/notif: implement notification stackingPavel Begunkov
The network stack allows only one ubuf_info per skb, and unlike MSG_ZEROCOPY, each io_uring zerocopy send will carry a separate ubuf_info. That means that send requests can't reuse a previosly allocated skb and need to get one more or more of new ones. That's fine for large sends, but otherwise it would spam the stack with lots of skbs carrying just a little data each. To help with that implement linking notification (i.e. an io_uring wrapper around ubuf_info) into a list. Each is refcounted by skbs and the stack as usual. additionally all non head entries keep a reference to the head, which they put down when their refcount hits 0. When the head have no more users, it'll efficiently put all notifications in a batch. As mentioned previously about ->io_link_skb, the callback implementation always allows to bind to an skb without a ubuf_info. Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/bf1e7f9b72f9ecc99999fdc0d2cded5eea87fd0b.1713369317.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22io_uring/notif: simplify io_notif_flush()Pavel Begunkov
io_notif_flush() is partially duplicating io_tx_ubuf_complete(), so instead of duplicating it, make the flush call io_tx_ubuf_complete. Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/19e41652c16718b946a5c80d2ad409df7682e47e.1713369317.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22Merge branch 'for-uring-ubufops' of ↵Jens Axboe
git://git.kernel.org/pub/scm/linux/kernel/git/kuba/linux into for-6.10/io_uring Merge net changes required for the upcoming send zerocopy improvements. * 'for-uring-ubufops' of git://git.kernel.org/pub/scm/linux/kernel/git/kuba/linux: net: add callback for setting a ubuf_info to skb net: extend ubuf_info callback to ops structure Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22net: add callback for setting a ubuf_info to skbPavel Begunkov
At the moment an skb can only have one ubuf_info associated with it, which might be a performance problem for zerocopy sends in cases like TCP via io_uring. Add a callback for assigning ubuf_info to skb, this way we will implement smarter assignment later like linking ubuf_info together. Note, it's an optional callback, which should be compatible with skb_zcopy_set(), that's because the net stack might potentially decide to clone an skb and take another reference to ubuf_info whenever it wishes. Also, a correct implementation should always be able to bind to an skb without prior ubuf_info, otherwise we could end up in a situation when the send would not be able to progress. Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/all/b7918aadffeb787c84c9e72e34c729dc04f3a45d.1713369317.git.asml.silence@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-04-22net: extend ubuf_info callback to ops structurePavel Begunkov
We'll need to associate additional callbacks with ubuf_info, introduce a structure holding ubuf_info callbacks. Apart from a more smarter io_uring notification management introduced in next patches, it can be used to generalise msg_zerocopy_put_abort() and also store ->sg_from_iter, which is currently passed in struct msghdr. Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/all/a62015541de49c0e2a8a0377a1d5d0a5aeb07016.1713369317.git.asml.silence@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-04-22io_uring/net: support bundles for recvJens Axboe
If IORING_OP_RECV is used with provided buffers, the caller may also set IORING_RECVSEND_BUNDLE to turn it into a multi-buffer recv. This grabs buffers available and receives into them, posting a single completion for all of it. This can be used with multishot receive as well, or without it. Now that both send and receive support bundles, add a feature flag for it as well. If IORING_FEAT_RECVSEND_BUNDLE is set after registering the ring, then the kernel supports bundles for recv and send. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22io_uring/net: support bundles for sendJens Axboe
If IORING_OP_SEND is used with provided buffers, the caller may also set IORING_RECVSEND_BUNDLE to turn it into a multi-buffer send. The idea is that an application can fill outgoing buffers in a provided buffer group, and then arm a single send that will service them all. Once there are no more buffers to send, or if the requested length has been sent, the request posts a single completion for all the buffers. This only enables it for IORING_OP_SEND, IORING_OP_SENDMSG is coming in a separate patch. However, this patch does do a lot of the prep work that makes wiring up the sendmsg variant pretty trivial. They share the prep side. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22io_uring/kbuf: add helpers for getting/peeking multiple buffersJens Axboe
Our provided buffer interface only allows selection of a single buffer. Add an API that allows getting/peeking multiple buffers at the same time. This is only implemented for the ring provided buffers. It could be added for the legacy provided buffers as well, but since it's strongly encouraged to use the new interface, let's keep it simpler and just provide it for the new API. The legacy interface will always just select a single buffer. There are two new main functions: io_buffers_select(), which selects up as many buffers as it can. The caller supplies the iovec array, and io_buffers_select() may allocate a bigger array if the 'out_len' being passed in is non-zero and bigger than what fits in the provided iovec. Buffers grabbed with this helper are permanently assigned. io_buffers_peek(), which works like io_buffers_select(), except they can be recycled, if needed. Callers using either of these functions should call io_put_kbufs() rather than io_put_kbuf() at completion time. The peek interface must be called with the ctx locked from peek to completion. This add a bit state for the request: - REQ_F_BUFFERS_COMMIT, which means that the the buffers have been peeked and should be committed to the buffer ring head when they are put as part of completion. Prior to this, req->buf_list was cleared to NULL when committed. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22io_uring/net: add provided buffer support for IORING_OP_SENDJens Axboe
It's pretty trivial to wire up provided buffer support for the send side, just like how it's done the receive side. This enables setting up a buffer ring that an application can use to push pending sends to, and then have a send pick a buffer from that ring. One of the challenges with async IO and networking sends is that you can get into reordering conditions if you have more than one inflight at the same time. Consider the following scenario where everything is fine: 1) App queues sendA for socket1 2) App queues sendB for socket1 3) App does io_uring_submit() 4) sendA is issued, completes successfully, posts CQE 5) sendB is issued, completes successfully, posts CQE All is fine. Requests are always issued in-order, and both complete inline as most sends do. However, if we're flooding socket1 with sends, the following could also result from the same sequence: 1) App queues sendA for socket1 2) App queues sendB for socket1 3) App does io_uring_submit() 4) sendA is issued, socket1 is full, poll is armed for retry 5) Space frees up in socket1, this triggers sendA retry via task_work 6) sendB is issued, completes successfully, posts CQE 7) sendA is retried, completes successfully, posts CQE Now we've sent sendB before sendA, which can make things unhappy. If both sendA and sendB had been using provided buffers, then it would look as follows instead: 1) App queues dataA for sendA, queues sendA for socket1 2) App queues dataB for sendB queues sendB for socket1 3) App does io_uring_submit() 4) sendA is issued, socket1 is full, poll is armed for retry 5) Space frees up in socket1, this triggers sendA retry via task_work 6) sendB is issued, picks first buffer (dataA), completes successfully, posts CQE (which says "I sent dataA") 7) sendA is retried, picks first buffer (dataB), completes successfully, posts CQE (which says "I sent dataB") Now we've sent the data in order, and everybody is happy. It's worth noting that this also opens the door for supporting multishot sends, as provided buffers would be a prerequisite for that. Those can trigger either when new buffers are added to the outgoing ring, or (if stalled due to lack of space) when space frees up in the socket. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-22io_uring/net: add generic multishot retry helperJens Axboe
This is just moving io_recv_prep_retry() higher up so it can get used for sends as well, and rename it to be generically useful for both sends and receives. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-17io_uring/rw: ensure retry condition isn't lostJens Axboe
A previous commit removed the checking on whether or not it was possible to retry a request, since it's now possible to retry any of them. This would previously have caused the request to have been ended with an error, but now the retry condition can simply get lost instead. Cleanup the retry handling and always just punt it to task_work, which will queue it with io-wq appropriately. Reported-by: Changhui Zhong <czhong@redhat.com> Tested-by: Ming Lei <ming.lei@redhat.com> Fixes: cca6571381a0 ("io_uring/rw: cleanup retry path") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-17io-wq: Drop intermediate step between pending list and active workGabriel Krisman Bertazi
next_work is only used to make the work visible for cancellation. Instead, we can just directly write to cur_work before dropping the acct_lock and avoid the extra hop. Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20240416021054.3940-3-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-17io-wq: write next_work before dropping acct_lockGabriel Krisman Bertazi
Commit 361aee450c6e ("io-wq: add intermediate work step between pending list and active work") closed a race between a cancellation and the work being removed from the wq for execution. To ensure the request is always reachable by the cancellation, we need to move it within the wq lock, which also synchronizes the cancellation. But commit 42abc95f05bf ("io-wq: decouple work_list protection from the big wqe->lock") replaced the wq lock here and accidentally reintroduced the race by releasing the acct_lock too early. In other words: worker | cancellation work = io_get_next_work() | raw_spin_unlock(&acct->lock); | | | io_acct_cancel_pending_work | io_wq_worker_cancel() worker->next_work = work Using acct_lock is still enough since we synchronize on it on io_acct_cancel_pending_work. Fixes: 42abc95f05bf ("io-wq: decouple work_list protection from the big wqe->lock") Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de> Link: https://lore.kernel.org/r/20240416021054.3940-2-krisman@suse.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/sqpoll: work around a potential audit memory leakJens Axboe
kmemleak complains that there's a memory leak related to connect handling: unreferenced object 0xffff0001093bdf00 (size 128): comm "iou-sqp-455", pid 457, jiffies 4294894164 hex dump (first 32 bytes): 02 00 fa ea 7f 00 00 01 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 2e481b1a): [<00000000c0a26af4>] kmemleak_alloc+0x30/0x38 [<000000009c30bb45>] kmalloc_trace+0x228/0x358 [<000000009da9d39f>] __audit_sockaddr+0xd0/0x138 [<0000000089a93e34>] move_addr_to_kernel+0x1a0/0x1f8 [<000000000b4e80e6>] io_connect_prep+0x1ec/0x2d4 [<00000000abfbcd99>] io_submit_sqes+0x588/0x1e48 [<00000000e7c25e07>] io_sq_thread+0x8a4/0x10e4 [<00000000d999b491>] ret_from_fork+0x10/0x20 which can can happen if: 1) The command type does something on the prep side that triggers an audit call. 2) The thread hasn't done any operations before this that triggered an audit call inside ->issue(), where we have audit_uring_entry() and audit_uring_exit(). Work around this by issuing a blanket NOP operation before the SQPOLL does anything. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/notif: shrink account_pages to u32Pavel Begunkov
->account_pages is the number of pages we account against the user derived from unsigned len, it definitely fits into unsigned, which saves some space in struct io_notif_data. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/19f2687fcb36daa74d86f4a27bfb3d35cffec318.1713185320.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/notif: remove ctx var from io_notif_tw_completePavel Begunkov
We don't need ctx in the hottest path, i.e. registered buffers, let's get it only when we need it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/e7345e268ffaeaf79b4c8f3a5d019d6a87a3d1f1.1713185320.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/notif: refactor io_tx_ubuf_complete()Pavel Begunkov
Flip the dec_and_test "if", that makes the function extension easier in the future. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/43939e2b04dff03bff5d7227c98afedf951227b3.1713185320.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: ensure overflow entries are dropped when ring is exitingJens Axboe
A previous consolidation cleanup missed handling the case where the ring is dying, and __io_cqring_overflow_flush() doesn't flush entries if the CQ ring is already full. This is fine for the normal CQE overflow flushing, but if the ring is going away, we need to flush everything, even if it means simply freeing the overflown entries. Fixes: 6c948ec44b29 ("io_uring: consolidate overflow flushing") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/timeout: remove duplicate initialization of the io_timeout list.Ruyi Zhang
In the __io_timeout_prep function, the io_timeout list is initialized twice, removing the meaningless second initialization. Signed-off-by: Ruyi Zhang <ruyi.zhang@samsung.com> Link: https://lore.kernel.org/r/20240411055953.2029218-1-ruyi.zhang@samsung.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: consolidate overflow flushingPavel Begunkov
Consolidate __io_cqring_overflow_flush and io_cqring_overflow_kill() into a single function as it once was, it's easier to work with it this way. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/986b42c35e76a6be7aa0cdcda0a236a2222da3a7.1712708261.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: always lock __io_cqring_overflow_flushPavel Begunkov
Conditional locking is never great, in case of __io_cqring_overflow_flush(), which is a slow path, it's not justified. Don't handle IOPOLL separately, always grab uring_lock for overflow flushing. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/162947df299aa12693ac4b305dacedab32ec7976.1712708261.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: open code io_cqring_overflow_flush()Pavel Begunkov
There is only one caller of io_cqring_overflow_flush(), open code it Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a1fecd56d9dba923ed8d4d159727fa939d3baa2a.1712708261.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: remove extra SQPOLL overflow flushPavel Begunkov
c1edbf5f081be ("io_uring: flag SQPOLL busy condition to userspace") added an extra overflowed CQE flush in the SQPOLL submission path due to backpressure, which was later removed. Remove the flush and let io_cqring_wait() / iopoll handle it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2a83b0724ca6ca9d16c7d79a51b77c81876b2e39.1712708261.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: unexport io_req_cqe_overflow()Pavel Begunkov
There are no users of io_req_cqe_overflow() apart from io_uring.c, make it static. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/f4295eb2f9eb98d5db38c0578f57f0b86bfe0d8c.1712708261.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: separate header for exported net bitsPavel Begunkov
We're exporting some io_uring bits to networking, e.g. for implementing a net callback for io_uring cmds, but we don't want to expose more than needed. Add a separate header for networking. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David Wei <dw@davidwei.uk> Link: https://lore.kernel.org/r/20240409210554.1878789-1-dw@davidwei.uk Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/net: set MSG_ZEROCOPY for sendzc in advancePavel Begunkov
We can set MSG_ZEROCOPY at the preparation step, do it so we don't have to care about it later in the issue callback. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/c2c22aaa577624977f045979a6db2b9fb2e5648c.1712534031.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/net: get rid of io_notif_complete_tw_extPavel Begunkov
io_notif_complete_tw_ext() can be removed and combined with io_notif_complete_tw to make it simpler without sacrificing anything. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/025a124a5e20e2474a57e2f04f16c422eb83063c.1712534031.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/net: merge ubuf sendzc callbacksPavel Begunkov
Splitting io_tx_ubuf_callback_ext from io_tx_ubuf_callback is a pre mature optimisation that doesn't give us much. Merge the functions into one and reclaim some simplicity back. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d44d68f6f7add33a0dcf0b7fd7b73c2dc543604f.1712534031.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: return void from io_put_kbuf_comp()Ming Lei
The only caller doesn't handle the return value of io_put_kbuf_comp(), so change its return type into void. Also follow Jens's suggestion to rename it as io_put_kbuf_drop(). Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20240407132759.4056167-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: remove io_req_put_rsrc_locked()Pavel Begunkov
io_req_put_rsrc_locked() is a weird shim function around io_req_put_rsrc(). All calls to io_req_put_rsrc() require holding ->uring_lock, so we can just use it directly. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a195bc78ac3d2c6fbaea72976e982fe51e50ecdd.1712331455.git.asml.silence@gmail.com Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: remove async request cachePavel Begunkov
io_req_complete_post() was a sole user of ->locked_free_list, but since we just gutted the function, the cache is not used anymore and can be removed. ->locked_free_list served as an asynhronous counterpart of the main request (i.e. struct io_kiocb) cache for all unlocked cases like io-wq. Now they're all forced to be completed into the main cache directly, off of the normal completion path or via io_free_req(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/7bffccd213e370abd4de480e739d8b08ab6c1326.1712331455.git.asml.silence@gmail.com Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: turn implicit assumptions into a warningPavel Begunkov
io_req_complete_post() is now io-wq only and shouldn't be used outside of it, i.e. it relies that io-wq holds a ref for the request as explained in a comment below. Let's add a warning to enforce the assumption and make sure nobody would try to do anything weird. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/1013b60c35d431d0698cafbc53c06f5917348c20.1712331455.git.asml.silence@gmail.com Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: kill dead code in io_req_complete_postMing Lei
Since commit 8f6c829491fe ("io_uring: remove struct io_tw_state::locked"), io_req_complete_post() is only called from io-wq submit work, where the request reference is guaranteed to be grabbed and won't drop to zero in io_req_complete_post(). Kill the dead code, meantime add req_ref_put() to put the reference. Cc: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/1d8297e2046553153e763a52574f0e0f4d512f86.1712331455.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/kbuf: remove dead defineJens Axboe
We no longer use IO_BUFFER_LIST_BUF_PER_PAGE, kill it. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: fix warnings on shadow variablesJens Axboe
There are a few of those: io_uring/fdinfo.c:170:16: warning: declaration shadows a local variable [-Wshadow] 170 | struct file *f = io_file_from_index(&ctx->file_table, i); | ^ io_uring/fdinfo.c:53:67: note: previous declaration is here 53 | __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f) | ^ io_uring/cancel.c:187:25: warning: declaration shadows a local variable [-Wshadow] 187 | struct io_uring_task *tctx = node->task->io_uring; | ^ io_uring/cancel.c:166:31: note: previous declaration is here 166 | struct io_uring_task *tctx, | ^ io_uring/register.c:371:25: warning: declaration shadows a local variable [-Wshadow] 371 | struct io_uring_task *tctx = node->task->io_uring; | ^ io_uring/register.c:312:24: note: previous declaration is here 312 | struct io_uring_task *tctx = NULL; | ^ and a simple cleanup gets rid of them. For the fdinfo case, make a distinction between the file being passed in (for the ring), and the registered files we iterate. For the other two cases, just get rid of shadowed variable, there's no reason to have a new one. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: move mapping/allocation helpers to a separate fileJens Axboe
Move the related code from io_uring.c into memmap.c. No functional changes in this patch, just cleaning it up a bit now that the full transition is done. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: use unpin_user_pages() where appropriateJens Axboe
There are a few cases of open-rolled loops around unpin_user_page(), use the generic helper instead. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/kbuf: use vm_insert_pages() for mmap'ed pbuf ringJens Axboe
Rather than use remap_pfn_range() for this and manually free later, switch to using vm_insert_page() and have it Just Work. This requires a bit of effort on the mmap lookup side, as the ctx uring_lock isn't held, which otherwise protects buffer_lists from being torn down, and it's not safe to grab from mmap context that would introduce an ABBA deadlock between the mmap lock and the ctx uring_lock. Instead, lookup the buffer_list under RCU, as the the list is RCU freed already. Use the existing reference count to determine whether it's possible to safely grab a reference to it (eg if it's not zero already), and drop that reference when done with the mapping. If the mmap reference is the last one, the buffer_list and the associated memory can go away, since the vma insertion has references to the inserted pages at that point. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring/kbuf: vmap pinned buffer ringJens Axboe
This avoids needing to care about HIGHMEM, and it makes the buffer indexing easier as both ring provided buffer methods are now virtually mapped in a contigious fashion. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: unify io_pin_pages()Jens Axboe
Move it into io_uring.c where it belongs, and use it in there as well rather than have two implementations of this. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: use vmap() for ring mappingJens Axboe
This is the last holdout which does odd page checking, convert it to vmap just like what is done for the non-mmap path. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15io_uring: get rid of remap_pfn_range() for mapping rings/sqesJens Axboe
Rather than use remap_pfn_range() for this and manually free later, switch to using vm_insert_pages() and have it Just Work. If possible, allocate a single compound page that covers the range that is needed. If that works, then we can just use page_address() on that page. If we fail to get a compound page, allocate single pages and use vmap() to map them into the kernel virtual address space. This just covers the rings/sqes, the other remaining user of the mmap remap_pfn_range() user will be converted separately. Once that is done, we can kill the old alloc/free code. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-04-15mm: add nommu variant of vm_insert_pages()Jens Axboe
An identical one exists for vm_insert_page(), add one for vm_insert_pages() to avoid needing to check for CONFIG_MMU in code using it. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>