From 50c1df2b56e0f581b1dbf334dbf807d6fb8f77b2 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 27 Aug 2021 17:11:06 -0600 Subject: [PATCH] io_uring: support CLOCK_BOOTTIME/REALTIME for timeouts Certain use cases want to use CLOCK_BOOTTIME or CLOCK_REALTIME rather than CLOCK_MONOTONIC, instead of the default CLOCK_MONOTONIC. Add an IORING_TIMEOUT_BOOTTIME and IORING_TIMEOUT_REALTIME flag that allows timeouts and linked timeouts to use the selected clock source. Only one clock source may be selected, and we -EINVAL the request if more than one is given. If neither BOOTIME nor REALTIME are selected, the previous default of MONOTONIC is used. Link: https://github.com/axboe/liburing/issues/369 Signed-off-by: Jens Axboe --- fs/io_uring.c | 27 ++++++++++++++++++++++++--- include/uapi/linux/io_uring.h | 3 +++ 2 files changed, 27 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index edbda88142f9..1c99f0143b57 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -508,6 +508,7 @@ struct io_timeout_data { struct hrtimer timer; struct timespec64 ts; enum hrtimer_mode mode; + u32 flags; }; struct io_accept { @@ -5712,6 +5713,22 @@ static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data) return 0; } +static clockid_t io_timeout_get_clock(struct io_timeout_data *data) +{ + switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) { + case IORING_TIMEOUT_BOOTTIME: + return CLOCK_BOOTTIME; + case IORING_TIMEOUT_REALTIME: + return CLOCK_REALTIME; + default: + /* can't happen, vetted at prep time */ + WARN_ON_ONCE(1); + fallthrough; + case 0: + return CLOCK_MONOTONIC; + } +} + static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data, struct timespec64 *ts, enum hrtimer_mode mode) __must_hold(&ctx->timeout_lock) @@ -5725,7 +5742,7 @@ static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data, req->timeout.off = 0; /* noseq */ data = req->async_data; list_add_tail(&req->timeout.list, &ctx->timeout_list); - hrtimer_init(&data->timer, CLOCK_MONOTONIC, mode); + hrtimer_init(&data->timer, io_timeout_get_clock(data), mode); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode); return 0; @@ -5807,7 +5824,10 @@ static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (off && is_timeout_link) return -EINVAL; flags = READ_ONCE(sqe->timeout_flags); - if (flags & ~IORING_TIMEOUT_ABS) + if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK)) + return -EINVAL; + /* more than one clock specified is invalid, obviously */ + if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1) return -EINVAL; req->timeout.off = off; @@ -5819,12 +5839,13 @@ static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, data = req->async_data; data->req = req; + data->flags = flags; if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr))) return -EFAULT; data->mode = io_translate_timeout_mode(flags); - hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode); + hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode); if (is_timeout_link) { struct io_submit_link *link = &req->ctx->submit_state.link; diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 64fe809c4e36..b6d28d927a3f 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -151,6 +151,9 @@ enum { */ #define IORING_TIMEOUT_ABS (1U << 0) #define IORING_TIMEOUT_UPDATE (1U << 1) +#define IORING_TIMEOUT_BOOTTIME (1U << 2) +#define IORING_TIMEOUT_REALTIME (1U << 3) +#define IORING_TIMEOUT_CLOCK_MASK (IORING_TIMEOUT_BOOTTIME | IORING_TIMEOUT_REALTIME) /* * sqe->splice_flags