From bc24d6bd32df0be19df3d30e74be4ba56493c0e2 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 12 Jul 2022 21:52:42 +0100 Subject: io_uring: add notification slot registration Let the userspace to register and unregister notification slots. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/a0aa8161fe3ebb2a4cc6e5dbd0cffb96e6881cf5.1657643355.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 17 +++++++++++++++++ io_uring/io_uring.c | 9 +++++++++ io_uring/notif.c | 43 +++++++++++++++++++++++++++++++++++++++++++ io_uring/notif.h | 3 +++ 4 files changed, 72 insertions(+) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 4c9b11e2e991..dcfc7a0bda0c 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -457,6 +457,10 @@ enum { /* register a range of fixed file slots for automatic slot allocation */ IORING_REGISTER_FILE_ALLOC_RANGE = 25, + /* zerocopy notification API */ + IORING_REGISTER_NOTIFIERS = 26, + IORING_UNREGISTER_NOTIFIERS = 27, + /* this goes last */ IORING_REGISTER_LAST }; @@ -503,6 +507,19 @@ struct io_uring_rsrc_update2 { __u32 resv2; }; +struct io_uring_notification_slot { + __u64 tag; + __u64 resv[3]; +}; + +struct io_uring_notification_register { + __u32 nr_slots; + __u32 resv; + __u64 resv2; + __u64 data; + __u64 resv3; +}; + /* Skip updating fd indexes set to this value in the fd table */ #define IORING_REGISTER_FILES_SKIP (-2) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 20e65d45ca1c..cae11374456e 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3870,6 +3870,15 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, break; ret = io_register_file_alloc_range(ctx, arg); break; + case IORING_REGISTER_NOTIFIERS: + ret = io_notif_register(ctx, arg, nr_args); + break; + case IORING_UNREGISTER_NOTIFIERS: + ret = -EINVAL; + if (arg || nr_args) + break; + ret = io_notif_unregister(ctx); + break; default: ret = -EINVAL; break; diff --git a/io_uring/notif.c b/io_uring/notif.c index 0a2e98bd74f6..e6d98dc208c7 100644 --- a/io_uring/notif.c +++ b/io_uring/notif.c @@ -162,5 +162,48 @@ __cold int io_notif_unregister(struct io_ring_ctx *ctx) kvfree(ctx->notif_slots); ctx->notif_slots = NULL; ctx->nr_notif_slots = 0; + io_notif_cache_purge(ctx); + return 0; +} + +__cold int io_notif_register(struct io_ring_ctx *ctx, + void __user *arg, unsigned int size) + __must_hold(&ctx->uring_lock) +{ + struct io_uring_notification_slot __user *slots; + struct io_uring_notification_slot slot; + struct io_uring_notification_register reg; + unsigned i; + + if (ctx->nr_notif_slots) + return -EBUSY; + if (size != sizeof(reg)) + return -EINVAL; + if (copy_from_user(®, arg, sizeof(reg))) + return -EFAULT; + if (!reg.nr_slots || reg.nr_slots > IORING_MAX_NOTIF_SLOTS) + return -EINVAL; + if (reg.resv || reg.resv2 || reg.resv3) + return -EINVAL; + + slots = u64_to_user_ptr(reg.data); + ctx->notif_slots = kvcalloc(reg.nr_slots, sizeof(ctx->notif_slots[0]), + GFP_KERNEL_ACCOUNT); + if (!ctx->notif_slots) + return -ENOMEM; + + for (i = 0; i < reg.nr_slots; i++, ctx->nr_notif_slots++) { + struct io_notif_slot *notif_slot = &ctx->notif_slots[i]; + + if (copy_from_user(&slot, &slots[i], sizeof(slot))) { + io_notif_unregister(ctx); + return -EFAULT; + } + if (slot.resv[0] | slot.resv[1] | slot.resv[2]) { + io_notif_unregister(ctx); + return -EINVAL; + } + notif_slot->tag = slot.tag; + } return 0; } diff --git a/io_uring/notif.h b/io_uring/notif.h index 1dd48efb7744..00efe164bdc4 100644 --- a/io_uring/notif.h +++ b/io_uring/notif.h @@ -6,6 +6,7 @@ #include #define IO_NOTIF_SPLICE_BATCH 32 +#define IORING_MAX_NOTIF_SLOTS (1U << 10) struct io_notif { struct ubuf_info uarg; @@ -48,6 +49,8 @@ struct io_notif_slot { u32 seq; }; +int io_notif_register(struct io_ring_ctx *ctx, + void __user *arg, unsigned int size); int io_notif_unregister(struct io_ring_ctx *ctx); void io_notif_cache_purge(struct io_ring_ctx *ctx); -- cgit v1.2.3