From d617b3147d54c42351eac63b5398d4ddf4f4011b Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 15 Nov 2024 16:54:43 +0000 Subject: io_uring: restore back registered wait arguments Now we've got a more generic region registration API, place IORING_ENTER_EXT_ARG_REG and re-enable it. First, the user has to register a region with the IORING_MEM_REGION_REG_WAIT_ARG flag set. It can only be done for a ring in a disabled state, aka IORING_SETUP_R_DISABLED, to avoid races with already running waiters. With that we should have stable constant values for ctx->cq_wait_{size,arg} in io_get_ext_arg_reg() and hence no READ_ONCE required. The other API difference is that we're now passing byte offsets instead of indexes. The user _must_ align all offsets / pointers to the native word size, failing to do so might but not necessarily has to lead to a failure usually returned as -EFAULT. liburing will be hiding this details from users. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/81822c1b4ffbe8ad391b4f9ad1564def0d26d990.1731689588.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 1ee35890125b..4418d0192959 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -663,6 +663,11 @@ struct io_uring_region_desc { __u64 __resv[4]; }; +enum { + /* expose the region as registered wait arguments */ + IORING_MEM_REGION_REG_WAIT_ARG = 1, +}; + struct io_uring_mem_region_reg { __u64 region_uptr; /* struct io_uring_region_desc * */ __u64 flags; -- cgit v1.2.3