Hi, This adds support for IORING_OP_WAITID, which is an async variant of the waitid(2) syscall. Rather than have a parent need to block waiting on a child task state change, it can now simply get an async notication when the requested state change has occured. Patches 1..4 are purely prep patches, and should not have functional changes. They split out parts of do_wait() into __do_wait(), so that the prepare-to-wait and sleep parts are contained within do_wait(). Patch 5 adds io_uring support. I wrote a few basic tests for this, which can be found in the 'waitid' branch of liburing: https://git.kernel.dk/cgit/liburing/log/?h=waitid Also spun a custom kernel for someone to test it, and no issues reported so far. include/linux/io_uring_types.h | 2 + include/uapi/linux/io_uring.h | 2 + io_uring/Makefile | 2 +- io_uring/cancel.c | 5 + io_uring/io_uring.c | 3 + io_uring/opdef.c | 9 + io_uring/waitid.c | 312 +++++++++++++++++++++++++++++++++ io_uring/waitid.h | 15 ++ kernel/exit.c | 129 ++++++++------ kernel/exit.h | 30 ++++ 10 files changed, 450 insertions(+), 59 deletions(-) The code can also be found here: https://git.kernel.dk/cgit/linux/log/?h=io_uring-waitid Changes since v2: - Get rid of 'f_flags' in kernel_waitid_prepare() (Christian) -- Jens Axboe
