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authorPavel Begunkov <asml.silence@gmail.com>2022-12-07 06:53:36 +0300
committerJens Axboe <axboe@kernel.dk>2022-12-07 18:50:57 +0300
commit6d043ee1164ca3305738131f170e560587070fa9 (patch)
tree67f4858e877e67894abad983f81c6c7e8a736e79 /io_uring
parent172113101641cf1f9628c528ec790cb809f2b704 (diff)
downloadlinux-6d043ee1164ca3305738131f170e560587070fa9.tar.xz
io_uring: do msg_ring in target task via tw
While executing in a context of one io_uring instance msg_ring manipulates another ring. We're trying to keep CQEs posting contained in the context of the ring-owner task, use task_work to send the request to the target ring's task when we're modifying its CQ or trying to install a file. Note, we can't safely use io_uring task_work infra and have to use task_work directly. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/4d76c7b28ed5d71b520de4482fbb7f660f21cd80.1670384893.git.asml.silence@gmail.com [axboe: use TWA_SIGNAL_NO_IPI] Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/msg_ring.c56
1 files changed, 53 insertions, 3 deletions
diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c
index 525063ac3dab..a1accf342079 100644
--- a/io_uring/msg_ring.c
+++ b/io_uring/msg_ring.c
@@ -16,6 +16,7 @@
struct io_msg {
struct file *file;
struct file *src_file;
+ struct callback_head tw;
u64 user_data;
u32 len;
u32 cmd;
@@ -35,6 +36,23 @@ void io_msg_ring_cleanup(struct io_kiocb *req)
msg->src_file = NULL;
}
+static void io_msg_tw_complete(struct callback_head *head)
+{
+ struct io_msg *msg = container_of(head, struct io_msg, tw);
+ struct io_kiocb *req = cmd_to_io_kiocb(msg);
+ struct io_ring_ctx *target_ctx = req->file->private_data;
+ int ret = 0;
+
+ if (current->flags & PF_EXITING)
+ ret = -EOWNERDEAD;
+ else if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
+ ret = -EOVERFLOW;
+
+ if (ret < 0)
+ req_set_fail(req);
+ io_req_queue_tw_complete(req, ret);
+}
+
static int io_msg_ring_data(struct io_kiocb *req)
{
struct io_ring_ctx *target_ctx = req->file->private_data;
@@ -43,6 +61,15 @@ static int io_msg_ring_data(struct io_kiocb *req)
if (msg->src_fd || msg->dst_fd || msg->flags)
return -EINVAL;
+ if (target_ctx->task_complete && current != target_ctx->submitter_task) {
+ init_task_work(&msg->tw, io_msg_tw_complete);
+ if (task_work_add(target_ctx->submitter_task, &msg->tw,
+ TWA_SIGNAL_NO_IPI))
+ return -EOWNERDEAD;
+
+ return IOU_ISSUE_SKIP_COMPLETE;
+ }
+
if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
return 0;
@@ -124,6 +151,19 @@ out_unlock:
return ret;
}
+static void io_msg_tw_fd_complete(struct callback_head *head)
+{
+ struct io_msg *msg = container_of(head, struct io_msg, tw);
+ struct io_kiocb *req = cmd_to_io_kiocb(msg);
+ int ret = -EOWNERDEAD;
+
+ if (!(current->flags & PF_EXITING))
+ ret = io_msg_install_complete(req, IO_URING_F_UNLOCKED);
+ if (ret < 0)
+ req_set_fail(req);
+ io_req_queue_tw_complete(req, ret);
+}
+
static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_ring_ctx *target_ctx = req->file->private_data;
@@ -140,6 +180,15 @@ static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
msg->src_file = src_file;
req->flags |= REQ_F_NEED_CLEANUP;
}
+
+ if (target_ctx->task_complete && current != target_ctx->submitter_task) {
+ init_task_work(&msg->tw, io_msg_tw_fd_complete);
+ if (task_work_add(target_ctx->submitter_task, &msg->tw,
+ TWA_SIGNAL))
+ return -EOWNERDEAD;
+
+ return IOU_ISSUE_SKIP_COMPLETE;
+ }
return io_msg_install_complete(req, issue_flags);
}
@@ -185,10 +234,11 @@ int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
}
done:
- if (ret == -EAGAIN)
- return -EAGAIN;
- if (ret < 0)
+ if (ret < 0) {
+ if (ret == -EAGAIN || ret == IOU_ISSUE_SKIP_COMPLETE)
+ return ret;
req_set_fail(req);
+ }
io_req_set_res(req, ret, 0);
return IOU_OK;
}