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authorJens Axboe <axboe@kernel.dk>2019-04-11 11:45:41 -0600
committerJens Axboe <axboe@kernel.dk>2019-05-02 14:08:54 -0600
commit9b402849e80c85eee10bbd341aab3f1a0f942d4f (patch)
treea4b43d48fad87c7e3f8996729e501f02d6c5a5cf /fs/io_uring.c
parent5d17b4a4b7fa172b205be8a05051ae705d1dc3bb (diff)
io_uring: add support for eventfd notifications
Allow registration of an eventfd, which will trigger an event every time a completion event happens for this io_uring instance. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
-rw-r--r--fs/io_uring.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 468f9da472b2..2a46de56d05c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -241,6 +241,7 @@ struct io_ring_ctx {
unsigned cq_mask;
struct wait_queue_head cq_wait;
struct fasync_struct *cq_fasync;
+ struct eventfd_ctx *cq_ev_fd;
} ____cacheline_aligned_in_smp;
/*
@@ -516,6 +517,8 @@ static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
wake_up(&ctx->wait);
if (waitqueue_active(&ctx->sqo_wait))
wake_up(&ctx->sqo_wait);
+ if (ctx->cq_ev_fd)
+ eventfd_signal(ctx->cq_ev_fd, 1);
}
static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 user_data,
@@ -2757,6 +2760,38 @@ err:
return ret;
}
+static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
+{
+ __s32 __user *fds = arg;
+ int fd;
+
+ if (ctx->cq_ev_fd)
+ return -EBUSY;
+
+ if (copy_from_user(&fd, fds, sizeof(*fds)))
+ return -EFAULT;
+
+ ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
+ if (IS_ERR(ctx->cq_ev_fd)) {
+ int ret = PTR_ERR(ctx->cq_ev_fd);
+ ctx->cq_ev_fd = NULL;
+ return ret;
+ }
+
+ return 0;
+}
+
+static int io_eventfd_unregister(struct io_ring_ctx *ctx)
+{
+ if (ctx->cq_ev_fd) {
+ eventfd_ctx_put(ctx->cq_ev_fd);
+ ctx->cq_ev_fd = NULL;
+ return 0;
+ }
+
+ return -ENXIO;
+}
+
static void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
io_finish_async(ctx);
@@ -2766,6 +2801,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
io_iopoll_reap_events(ctx);
io_sqe_buffer_unregister(ctx);
io_sqe_files_unregister(ctx);
+ io_eventfd_unregister(ctx);
#if defined(CONFIG_UNIX)
if (ctx->ring_sock)
@@ -3179,6 +3215,18 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
break;
ret = io_sqe_files_unregister(ctx);
break;
+ case IORING_REGISTER_EVENTFD:
+ ret = -EINVAL;
+ if (nr_args != 1)
+ break;
+ ret = io_eventfd_register(ctx, arg);
+ break;
+ case IORING_UNREGISTER_EVENTFD:
+ ret = -EINVAL;
+ if (arg || nr_args)
+ break;
+ ret = io_eventfd_unregister(ctx);
+ break;
default:
ret = -EINVAL;
break;