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2020-03-02io_uring: use poll driven retry for files that support itJens Axboe
Currently io_uring tries any request in a non-blocking manner, if it can, and then retries from a worker thread if we get -EAGAIN. Now that we have a new and fancy poll based retry backend, use that to retry requests if the file supports it. This means that, for example, an IORING_OP_RECVMSG on a socket no longer requires an async thread to complete the IO. If we get -EAGAIN reading from the socket in a non-blocking manner, we arm a poll handler for notification on when the socket becomes readable. When it does, the pending read is executed directly by the task again, through the io_uring task work handlers. Not only is this faster and more efficient, it also means we're not generating potentially tons of async threads that just sit and block, waiting for the IO to complete. The feature is marked with IORING_FEAT_FAST_POLL, meaning that async pollable IO is fast, and that poll<link>other_op is fast as well. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: mark requests that we can do poll async in io_op_defsJens Axboe
Add a pollin/pollout field to the request table, and have commands that we can safely poll for properly marked. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: add per-task callback handlerJens Axboe
For poll requests, it's not uncommon to link a read (or write) after the poll to execute immediately after the file is marked as ready. Since the poll completion is called inside the waitqueue wake up handler, we have to punt that linked request to async context. This slows down the processing, and actually means it's faster to not use a link for this use case. We also run into problems if the completion_lock is contended, as we're doing a different lock ordering than the issue side is. Hence we have to do trylock for completion, and if that fails, go async. Poll removal needs to go async as well, for the same reason. eventfd notification needs special case as well, to avoid stack blowing recursion or deadlocks. These are all deficiencies that were inherited from the aio poll implementation, but I think we can do better. When a poll completes, simply queue it up in the task poll list. When the task completes the list, we can run dependent links inline as well. This means we never have to go async, and we can remove a bunch of code associated with that, and optimizations to try and make that run faster. The diffstat speaks for itself. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: store io_kiocb in wait->privateJens Axboe
Store the io_kiocb in the private field instead of the poll entry, this is in preparation for allowing multiple waitqueues. No functional changes in this patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: remove IO_WQ_WORK_CBPavel Begunkov
IO_WQ_WORK_CB is used only for linked timeouts, which will be armed before the work setup (i.e. mm, override creds, etc). The setup shouldn't take long, so it's ok to arm it a bit later and get rid of IO_WQ_WORK_CB. Make io-wq call work->func() only once, callbacks will handle the rest. i.e. the linked timeout handler will do the actual issue. And as a bonus, it removes an extra indirect call. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: extract kmsg copy helperPavel Begunkov
io_recvmsg() and io_sendmsg() duplicate nonblock -EAGAIN finilising part, so add helper for that. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: clean io_poll_completePavel Begunkov
Deduplicate call to io_cqring_fill_event(), plain and easy Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: add splice(2) supportPavel Begunkov
Add support for splice(2). - output file is specified as sqe->fd, so it's handled by generic code - hash_reg_file handled by generic code as well - len is 32bit, but should be fine - the fd_in is registered file, when SPLICE_F_FD_IN_FIXED is set, which is a splice flag (i.e. sqe->splice_flags). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: add interface for getting filesPavel Begunkov
Preparation without functional changes. Adds io_get_file(), that allows to grab files not only into req->file. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: remove req->in_asyncPavel Begunkov
req->in_async is not really needed, it only prevents propagation of @nxt for fast not-blocked submissions. Remove it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: don't do full *prep_worker() from io-wqPavel Begunkov
io_prep_async_worker() called io_wq_assign_next() do many useless checks: io_req_work_grab_env() was already called during prep, and @do_hashed is not ever used. Add io_prep_next_work() -- simplified version, that can be called io-wq. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: don't call work.func from sync ctxPavel Begunkov
Many operations define custom work.func before getting into an io-wq. There are several points against: - it calls io_wq_assign_next() from outside io-wq, that may be confusing - sync context would go unnecessary through io_req_cancelled() - prototypes are quite different, so work!=old_work looks strange - makes async/sync responsibilities fuzzy - adds extra overhead Don't call generic path and io-wq handlers from each other, but use helpers instead Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: io_accept() should hold on to submit reference on retryJens Axboe
Don't drop an early reference, hang on to it and let the caller drop it. This makes it behave more like "regular" requests. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-03-02io_uring: consider any io_read/write -EAGAIN as finalJens Axboe
If the -EAGAIN happens because of a static condition, then a poll or later retry won't fix it. We must call it again from blocking condition. Play it safe and ensure that any -EAGAIN condition from read or write must retry from async context. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-27io_uring: fix 32-bit compatability with sendmsg/recvmsgJens Axboe
We must set MSG_CMSG_COMPAT if we're in compatability mode, otherwise the iovec import for these commands will not do the right thing and fail the command with -EINVAL. Found by running the test suite compiled as 32-bit. Cc: stable@vger.kernel.org Fixes: aa1fa28fc73e ("io_uring: add support for recvmsg()") Fixes: 0fa03c624d8f ("io_uring: add support for sendmsg()") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-27io_uring: define and set show_fdinfo only if procfs is enabledTobias Klauser
Follow the pattern used with other *_show_fdinfo functions and only define and use io_uring_show_fdinfo and its helper functions if CONFIG_PROC_FS is set. Fixes: 87ce955b24c9 ("io_uring: add ->show_fdinfo() for the io_uring file descriptor") Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-26io_uring: drop file set ref put/get on switchJens Axboe
Dan reports that he triggered a warning on ring exit doing some testing: percpu ref (io_file_data_ref_zero) <= 0 (0) after switching to atomic WARNING: CPU: 3 PID: 0 at lib/percpu-refcount.c:160 percpu_ref_switch_to_atomic_rcu+0xe8/0xf0 Modules linked in: CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.6.0-rc3+ #5648 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 RIP: 0010:percpu_ref_switch_to_atomic_rcu+0xe8/0xf0 Code: e7 ff 55 e8 eb d2 80 3d bd 02 d2 00 00 75 8b 48 8b 55 d8 48 c7 c7 e8 70 e6 81 c6 05 a9 02 d2 00 01 48 8b 75 e8 e8 3a d0 c5 ff <0f> 0b e9 69 ff ff ff 90 55 48 89 fd 53 48 89 f3 48 83 ec 28 48 83 RSP: 0018:ffffc90000110ef8 EFLAGS: 00010292 RAX: 0000000000000045 RBX: 7fffffffffffffff RCX: 0000000000000000 RDX: 0000000000000045 RSI: ffffffff825be7a5 RDI: ffffffff825bc32c RBP: ffff8881b75eac38 R08: 000000042364b941 R09: 0000000000000045 R10: ffffffff825beb40 R11: ffffffff825be78a R12: 0000607e46005aa0 R13: ffff888107dcdd00 R14: 0000000000000000 R15: 0000000000000009 FS: 0000000000000000(0000) GS:ffff8881b9d80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f49e6a5ea20 CR3: 00000001b747c004 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> rcu_core+0x1e4/0x4d0 __do_softirq+0xdb/0x2f1 irq_exit+0xa0/0xb0 smp_apic_timer_interrupt+0x60/0x140 apic_timer_interrupt+0xf/0x20 </IRQ> RIP: 0010:default_idle+0x23/0x170 Code: ff eb ab cc cc cc cc 0f 1f 44 00 00 41 54 55 53 65 8b 2d 10 96 92 7e 0f 1f 44 00 00 e9 07 00 00 00 0f 00 2d 21 d0 51 00 fb f4 <65> 8b 2d f6 95 92 7e 0f 1f 44 00 00 5b 5d 41 5c c3 65 8b 05 e5 95 Turns out that this is due to percpu_ref_switch_to_atomic() only grabbing a reference to the percpu refcount if it's not already in atomic mode. io_uring drops a ref and re-gets it when switching back to percpu mode. We attempt to protect against this with the FFD_F_ATOMIC bit, but that isn't reliable. We don't actually need to juggle these refcounts between atomic and percpu switch, we can just do them when we've switched to atomic mode. This removes the need for FFD_F_ATOMIC, which wasn't reliable. Fixes: 05f3fb3c5397 ("io_uring: avoid ring quiesce for fixed file set unregister and update") Reported-by: Dan Melnic <dmm@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-26io_uring: import_single_range() returns 0/-ERRORJens Axboe
Unlike the other core import helpers, import_single_range() returns 0 on success, not the length imported. This means that links that depend on the result of non-vec based IORING_OP_{READ,WRITE} that were added for 5.5 get errored when they should not be. Fixes: 3a6820f2bb8a ("io_uring: add non-vectored read/write commands") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-26io_uring: pick up link work on submit reference dropJens Axboe
If work completes inline, then we should pick up a dependent link item in __io_queue_sqe() as well. If we don't do so, we're forced to go async with that item, which is suboptimal. This also fixes an issue with io_put_req_find_next(), which always looks up the next work item. That should only be done if we're dropping the last reference to the request, to prevent multiple lookups of the same work item. Outside of being a fix, this also enables a good cleanup series for 5.7, where we never have to pass 'nxt' around or into the work handlers. Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-25io_uring: fix poll_list race for SETUP_IOPOLL|SETUP_SQPOLLXiaoguang Wang
After making ext4 support iopoll method: let ext4_file_operations's iopoll method be iomap_dio_iopoll(), we found fio can easily hang in fio_ioring_getevents() with below fio job: rm -f testfile; sync; sudo fio -name=fiotest -filename=testfile -iodepth=128 -thread -rw=write -ioengine=io_uring -hipri=1 -sqthread_poll=1 -direct=1 -bs=4k -size=10G -numjobs=8 -runtime=2000 -group_reporting with IORING_SETUP_SQPOLL and IORING_SETUP_IOPOLL enabled. There are two issues that results in this hang, one reason is that when IORING_SETUP_SQPOLL and IORING_SETUP_IOPOLL are enabled, fio does not use io_uring_enter to get completed events, it relies on kernel io_sq_thread to poll for completed events. Another reason is that there is a race: when io_submit_sqes() in io_sq_thread() submits a batch of sqes, variable 'inflight' will record the number of submitted reqs, then io_sq_thread will poll for reqs which have been added to poll_list. But note, if some previous reqs have been punted to io worker, these reqs will won't be in poll_list timely. io_sq_thread() will only poll for a part of previous submitted reqs, and then find poll_list is empty, reset variable 'inflight' to be zero. If app just waits these deferred reqs and does not wake up io_sq_thread again, then hang happens. For app that entirely relies on io_sq_thread to poll completed requests, let io_iopoll_req_issued() wake up io_sq_thread properly when adding new element to poll_list, and when io_sq_thread prepares to sleep, check whether poll_list is empty again, if not empty, continue to poll. Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-24io_uring: fix personality idr leakJens Axboe
We somehow never free the idr, even though we init it for every ctx. Free it when the rest of the ring data is freed. Fixes: 071698e13ac6 ("io_uring: allow registering credentials") Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-23io_uring: handle multiple personalities in link chainsJens Axboe
If we have a chain of requests and they don't all use the same credentials, then the head of the chain will be issued with the credentails of the tail of the chain. Ensure __io_queue_sqe() overrides the credentials, if they are different. Once we do that, we can clean up the creds handling as well, by only having io_submit_sqe() do the lookup of a personality. It doesn't need to assign it, since __io_queue_sqe() now always does the right thing. Fixes: 75c6a03904e0 ("io_uring: support using a registered personality for commands") Reported-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-22io_uring: fix __io_iopoll_check deadlock in io_sq_threadXiaoguang Wang
Since commit a3a0e43fd770 ("io_uring: don't enter poll loop if we have CQEs pending"), if we already events pending, we won't enter poll loop. In case SETUP_IOPOLL and SETUP_SQPOLL are both enabled, if app has been terminated and don't reap pending events which are already in cq ring, and there are some reqs in poll_list, io_sq_thread will enter __io_iopoll_check(), and find pending events, then return, this loop will never have a chance to exit. I have seen this issue in fio stress tests, to fix this issue, let io_sq_thread call io_iopoll_getevents() with argument 'min' being zero, and remove __io_iopoll_check(). Fixes: a3a0e43fd770 ("io_uring: don't enter poll loop if we have CQEs pending") Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-21io_uring: prevent sq_thread from spinning when it should stopStefano Garzarella
This patch drops 'cur_mm' before calling cond_resched(), to prevent the sq_thread from spinning even when the user process is finished. Before this patch, if the user process ended without closing the io_uring fd, the sq_thread continues to spin until the 'sq_thread_idle' timeout ends. In the worst case where the 'sq_thread_idle' parameter is bigger than INT_MAX, the sq_thread will spin forever. Fixes: 6c271ce2f1d5 ("io_uring: add submission polling") Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-18io_uring: fix use-after-free by io_cleanup_req()Pavel Begunkov
io_cleanup_req() should be called before req->io is freed, and so shouldn't be after __io_free_req() -> __io_req_aux_free(). Also, it will be ignored for in io_free_req_many(), which use __io_req_aux_free(). Place cleanup_req() into __io_req_aux_free(). Fixes: 99bc4c38537d774 ("io_uring: fix iovec leaks") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-18io_uring: remove unnecessary NULL checksDan Carpenter
The "kmsg" pointer can't be NULL and we have already dereferenced it so a check here would be useless. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-16io_uring: add missing io_req_cancelled()Pavel Begunkov
fallocate_finish() is missing cancellation check. Add it. It's safe to do that, as only flags setup and sqe fields copy are done before it gets into __io_fallocate(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-13io_uring: prune request from overflow list on flushJens Axboe
Carter reported an issue where he could produce a stall on ring exit, when we're cleaning up requests that match the given file table. For this particular test case, a combination of a few things caused the issue: - The cq ring was overflown - The request being canceled was in the overflow list The combination of the above means that the cq overflow list holds a reference to the request. The request is canceled correctly, but since the overflow list holds a reference to it, the final put won't happen. Since the final put doesn't happen, the request remains in the inflight. Hence we never finish the cancelation flush. Fix this by removing requests from the overflow list if we're canceling them. Cc: stable@vger.kernel.org # 5.5 Reported-by: Carter Li 李通洲 <carter.li@eoitek.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-09io_uring: retain sockaddr_storage across send/recvmsg async puntJens Axboe
Jonas reports that he sometimes sees -97/-22 error returns from sendmsg, if it gets punted async. This is due to not retaining the sockaddr_storage between calls. Include that in the state we copy when going async. Cc: stable@vger.kernel.org # 5.3+ Reported-by: Jonas Bonn <jonas@norrbonn.se> Tested-by: Jonas Bonn <jonas@norrbonn.se> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-09io_uring: cancel pending async work if task exitsJens Axboe
Normally we cancel all work we track, but for untracked work we could leave the async worker behind until that work completes. This is totally fine, but does leave resources pending after the task is gone until that work completes. Cancel work that this task queued up when it goes away. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: fix openat/statx's filename leakPavel Begunkov
As in the previous patch, make openat*_prep() and statx_prep() handle double preparation to avoid resource leakage. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: fix double prep iovec leakPavel Begunkov
Requests may be prepared multiple times with ->io allocated (i.e. async prepared). Preparation functions don't handle it and forget about previously allocated resources. This may happen in case of: - spurious defer_check - non-head (i.e. async prepared) request executed in sync (via nxt). Make the handlers check, whether they already allocated resources, which is true IFF REQ_F_NEED_CLEANUP is set. Cc: stable@vger.kernel.org # 5.5 Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: fix async close() with f_op->flush()Pavel Begunkov
First, io_close() misses filp_close() and io_cqring_add_event(), when f_op->flush is defined. That's because in this case it will io_queue_async_work() itself not grabbing files, so the corresponding chunk in io_close_finish() won't be executed. Second, when submitted through io_wq_submit_work(), it will do filp_close() and *_add_event() twice: first inline in io_close(), and the second one in call to io_close_finish() from io_close(). The second one will also fire, because it was submitted async through generic path, and so have grabbed files. And the last nice thing is to remove this weird pilgrimage with checking work/old_work and casting it to nxt. Just use a helper instead. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: allow AT_FDCWD for non-file openat/openat2/statxJens Axboe
Don't just check for dirfd == -1, we should allow AT_FDCWD as well for relative lookups. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: grab ->fs as part of async preparationJens Axboe
This passes it in to io-wq, so it assumes the right fs_struct when executing async work that may need to do lookups. Cc: stable@vger.kernel.org # 5.3+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: retry raw bdev writes if we hit -EOPNOTSUPPJens Axboe
For non-blocking issue, we set IOCB_NOWAIT in the kiocb. However, on a raw block device, this yields an -EOPNOTSUPP return, as non-blocking writes aren't supported. Turn this -EOPNOTSUPP into -EAGAIN, so we retry from blocking context with IOCB_NOWAIT cleared. Cc: stable@vger.kernel.org # 5.5 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: add cleanup for openat()/statx()Pavel Begunkov
openat() and statx() may have allocated ->open.filename, which should be be put. Add cleanup handlers for them. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: fix iovec leaksPavel Begunkov
Allocated iovec is freed only in io_{read,write,send,recv)(), and just leaves it if an error occured. There are plenty of such cases: - cancellation of non-head requests - fail grabbing files in __io_queue_sqe() - set REQ_F_NOWAIT and returning in __io_queue_sqe() Add REQ_F_NEED_CLEANUP, which will force such requests with custom allocated resourses go through cleanup handlers on put. Cc: stable@vger.kernel.org # 5.5 Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: remove unused struct io_async_openPavel Begunkov
struct io_async_open is unused, remove it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: flush overflowed CQ events in the io_uring_poll()Stefano Garzarella
In io_uring_poll() we must flush overflowed CQ events before to check if there are CQ events available, to avoid missing events. We call the io_cqring_events() that checks and flushes any overflow and returns the number of CQ events available. Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08io_uring: statx/openat/openat2 don't support fixed filesJens Axboe
All of these opcodes take a directory file descriptor. We can't easily support fixed files for these operations, and the use case for that probably isn't all that clear (or sensible) anyway. Disable IOSQE_FIXED_FILE for these operations. Reported-by: Stefan Metzmacher <metze@samba.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06io_uring: fix deferred req iovec leakPavel Begunkov
After defer, a request will be prepared, that includes allocating iovec if needed, and then submitted through io_wq_submit_work() but not custom handler (e.g. io_rw_async()/io_sendrecv_async()). However, it'll leak iovec, as it's in io-wq and the code goes as follows: io_read() { if (!io_wq_current_is_worker()) kfree(iovec); } Put all deallocation logic in io_{read,write,send,recv}(), which will leave the memory, if going async with -EAGAIN. It also fixes a leak after failed io_alloc_async_ctx() in io_{recv,send}_msg(). Cc: stable@vger.kernel.org # 5.5 Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06io_uring: fix 1-bit bitfields to be unsignedRandy Dunlap
Make bitfields of size 1 bit be unsigned (since there is no room for the sign bit). This clears up the sparse warnings: CHECK ../fs/io_uring.c ../fs/io_uring.c:207:50: error: dubious one-bit signed bitfield ../fs/io_uring.c:208:55: error: dubious one-bit signed bitfield ../fs/io_uring.c:209:63: error: dubious one-bit signed bitfield ../fs/io_uring.c:210:54: error: dubious one-bit signed bitfield ../fs/io_uring.c:211:57: error: dubious one-bit signed bitfield Found by sight and then verified with sparse. Fixes: 69b3e546139a ("io_uring: change io_ring_ctx bool fields into bit fields") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: io-uring@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06io_uring: get rid of delayed mm checkPavel Begunkov
Fail fast if can't grab mm, so past that requests always have an mm when required. This allows us to remove req->user altogether. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06Merge tag 'io_uring-5.6-2020-02-05' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull io_uring updates from Jens Axboe: "Some later fixes for io_uring: - Small cleanup series from Pavel - Belt and suspenders build time check of sqe size and layout (Stefan) - Addition of ->show_fdinfo() on request of Jann Horn, to aid in understanding mapped personalities - eventfd recursion/deadlock fix, for both io_uring and aio - Fixup for send/recv handling - Fixup for double deferral of read/write request - Fix for potential double completion event for close request - Adjust fadvise advice async/inline behavior - Fix for shutdown hang with SQPOLL thread - Fix for potential use-after-free of fixed file table" * tag 'io_uring-5.6-2020-02-05' of git://git.kernel.dk/linux-block: io_uring: cleanup fixed file data table references io_uring: spin for sq thread to idle on shutdown aio: prevent potential eventfd recursion on poll io_uring: put the flag changing code in the same spot io_uring: iterate req cache backwards io_uring: punt even fadvise() WILLNEED to async context io_uring: fix sporadic double CQE entry for close io_uring: remove extra ->file check io_uring: don't map read/write iovec potentially twice io_uring: use the proper helpers for io_send/recv io_uring: prevent potential eventfd recursion on poll eventfd: track eventfd_signal() recursion depth io_uring: add BUILD_BUG_ON() to assert the layout of struct io_uring_sqe io_uring: add ->show_fdinfo() for the io_uring file descriptor
2020-02-04io_uring: cleanup fixed file data table referencesJens Axboe
syzbot reports a use-after-free in io_ring_file_ref_switch() when it tries to switch back to percpu mode. When we put the final reference to the table by calling percpu_ref_kill_and_confirm(), we don't want the zero reference to queue async work for flushing the potentially queued up items. We currently do a few flush_work(), but they merely paper around the issue, since the work item may not have been queued yet depending on the when the percpu-ref callback gets run. Coming into the file unregister, we know we have the ring quiesced. io_ring_file_ref_switch() can check for whether or not the ref is dying or not, and not queue anything async at that point. Once the ref has been confirmed killed, flush any potential items manually. Reported-by: syzbot+7caeaea49c2c8a591e3d@syzkaller.appspotmail.com Fixes: 05f3fb3c5397 ("io_uring: avoid ring quiesce for fixed file set unregister and update") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-04io_uring: spin for sq thread to idle on shutdownJens Axboe
As part of io_uring shutdown, we cancel work that is pending and won't necessarily complete on its own. That includes requests like poll commands and timeouts. If we're using SQPOLL for kernel side submission and we shutdown the ring immediately after queueing such work, we can race with the sqthread doing the submission. This means we may miss cancelling some work, which results in the io_uring shutdown hanging forever. Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03io_uring: put the flag changing code in the same spotPavel Begunkov
Both iocb_flags() and kiocb_set_rw_flags() are inline and modify kiocb->ki_flags. Place them close, so they can be potentially better optimised. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03io_uring: iterate req cache backwardsPavel Begunkov
Grab requests from cache-array from the end, so can get by only free_reqs. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03io_uring: punt even fadvise() WILLNEED to async contextJens Axboe
Andres correctly points out that read-ahead can block, if it needs to read in meta data (or even just through the page cache page allocations). Play it safe for now and just ensure WILLNEED is also punted to async context. While in there, allow the file settings hints from non-blocking context. They don't need to start/do IO, and we can safely do them inline. Fixes: 4840e418c2fc ("io_uring: add IORING_OP_FADVISE") Reported-by: Andres Freund <andres@anarazel.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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