kernel.git/io_uring/io_uring.c, branch linux-6.7.y

io_uring: clean rings on NO_MMAP alloc fail

2024-04-03T13:11:24Z

[ Upstream commit cef59d1ea7170ec753182302645a0191c8aa3382 ] We make a few cancellation judgements based on ctx->rings, so let's zero it afer deallocation for IORING_SETUP_NO_MMAP just like it's done with the mmap case. Likely, it's not a real problem, but zeroing is safer and better tested. Cc: stable@vger.kernel.org Fixes: 03d89a2de25bbc ("io_uring: support for user allocated memory for rings/sqes") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/9ff6cdf91429b8a51699c210e1f6af6ea3f8bdcf.1710255382.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: Fix release of pinned pages when __io_uaddr_map fails

2024-03-26T22:18:54Z

[ Upstream commit 67d1189d1095d471ed7fa426c7e384a7140a5dd7 ] Looking at the error path of __io_uaddr_map, if we fail after pinning the pages for any reasons, ret will be set to -EINVAL and the error handler won't properly release the pinned pages. I didn't manage to trigger it without forcing a failure, but it can happen in real life when memory is heavily fragmented. Signed-off-by: Gabriel Krisman Bertazi Fixes: 223ef4743164 ("io_uring: don't allow IORING_SETUP_NO_MMAP rings on highmem pages") Link: https://lore.kernel.org/r/20240313213912.1920-1-krisman@suse.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: don't save/restore iowait state

2024-03-26T22:18:52Z

[ Upstream commit 6f0974eccbf78baead1735722c4f1ee3eb9422cd ] This kind of state is per-syscall, and since we're doing the waiting off entering the io_uring_enter(2) syscall, there's no way that iowait can already be set for this case. Simplify it by setting it if we need to, and always clearing it to 0 when done. Fixes: 7b72d661f1f2 ("io_uring: gate iowait schedule on having pending requests") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: remove unconditional looping in local task_work handling

2024-03-26T22:17:58Z

[ Upstream commit 9fe3eaea4a3530ca34a8d8ff00b1848c528789ca ] If we have a ton of notifications coming in, we can be looping in here for a long time. This can be problematic for various reasons, mostly because we can starve userspace. If the application is waiting on N events, then only re-run if we need more events. Fixes: c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: remove looping around handling traditional task_work

2024-03-26T22:17:58Z

[ Upstream commit 592b4805432af075468876771c0f7d41273ccb3c ] A previous commit added looping around handling traditional task_work as an optimization, and while that may seem like a good idea, it's also possible to run into application starvation doing so. If the task_work generation is bursty, we can get very deep task_work queues, and we can end up looping in here for a very long time. One immediately observable problem with that is handling network traffic using provided buffers, where flooding incoming traffic and looping task_work handling will very quickly lead to buffer starvation as we keep running task_work rather than returning to the application so it can handle the associated CQEs and also provide buffers back. Fixes: 3a0c037b0e16 ("io_uring: batch task_work") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: drop any code related to SCM_RIGHTS

2024-03-26T22:17:49Z

Commit 6e5e6d274956305f1fc0340522b38f5f5be74bdb upstream. This is dead code after we dropped support for passing io_uring fds over SCM_RIGHTS, get rid of it. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring/unix: drop usage of io_uring socket

2024-03-26T22:17:49Z

Commit a4104821ad651d8a0b374f0b2474c345bbb42f82 upstream. Since we no longer allow sending io_uring fds over SCM_RIGHTS, move to using io_is_uring_fops() to detect whether this is a io_uring fd or not. With that done, kill off io_uring_get_socket() as nobody calls it anymore. This is in preparation to yanking out the rest of the core related to unix gc with io_uring. Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: adjust defer tw counting

2024-01-25T23:45:30Z

[ Upstream commit dc12d1799ce710fd90abbe0ced71e7e1ae0894fc ] The UINT_MAX work item counting bias in io_req_local_work_add() in case of !IOU_F_TWQ_LAZY_WAKE works in a sense that we will not miss a wake up, however it's still eerie. In particular, if we add a lazy work item after a non-lazy one, we'll increment it and get nr_tw==0, and subsequent adds may try to unnecessarily wake up the task, which is though not so likely to happen in real workloads. Half the bias, it's still large enough to be larger than any valid ->cq_wait_nr, which is limited by IORING_MAX_CQ_ENTRIES, but further have a good enough of space before it overflows. Fixes: 8751d15426a31 ("io_uring: reduce scheduling due to tw") Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/108b971e958deaf7048342930c341ba90f75d806.1705438669.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

io_uring: ensure local task_work is run on wait timeout

2024-01-25T23:45:13Z

commit 6ff1407e24e6fdfa4a16ba9ba551e3d253a26391 upstream. A previous commit added an earlier break condition here, which is fine if we're using non-local task_work as it'll be run on return to userspace. However, if DEFER_TASKRUN is used, then we could be leaving local task_work that is ready to process in the ctx list until next time that we enter the kernel to wait for events. Move the break condition to _after_ we have run task_work. Cc: stable@vger.kernel.org Fixes: 846072f16eed ("io_uring: mimimise io_cqring_wait_schedule") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring: don't check iopoll if request completes

2024-01-25T23:45:13Z

commit 9b43ef3d52532a0175ed6654618f7db61d390d2e upstream. IOPOLL request should never return IOU_OK, so the following iopoll queueing check in io_issue_sqe() after getting IOU_OK doesn't make any sense as would never turn true. Let's optimise on that and return a bit earlier. It's also much more resilient to potential bugs from mischieving iopoll implementations. Cc: Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/2f8690e2fa5213a2ff292fac29a7143c036cdd60.1701390926.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman