On 2/19/25 16:48, Pavel Begunkov wrote:
On 2/18/25 22:42, Keith Busch wrote:
From: Keith Busch <kbusch@xxxxxxxxxx>
Similar to the fixed file path, requests may depend on a previous one
to set up an index, so we need to allow linking them. The prep callback
happens too soon for linked commands, so the lookup needs to be deferred
to the issue path. Change the prep callbacks to just set the buf_index
and let generic io_uring code handle the fixed buffer node setup, just
like it already does for fixed files.
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
It wasn't great before, and it'd be harder to follow if we shove it
into the issue path like that. Add additional overhead in the common
path and that it's not super flexible, like the notification problem
and what we need out of it for other features.
We're better to remove the lookup vs import split like below.
Here is a branch, let's do it on top.
https://github.com/isilence/linux.git regbuf-import
diff --git a/io_uring/net.c b/io_uring/net.c
index ce0a39972cce..322cf023233a 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -1360,24 +1360,10 @@ static int io_send_zc_import(struct io_kiocb *req, unsigned int issue_flags)
...
-int io_import_fixed(int ddir, struct iov_iter *iter,
- struct io_mapped_ubuf *imu,
- u64 buf_addr, size_t len)
+static int io_import_fixed_imu(int ddir, struct iov_iter *iter,
+ struct io_mapped_ubuf *imu,
+ u64 buf_addr, size_t len)
{
u64 buf_end;
size_t offset;
@@ -919,6 +919,35 @@ int io_import_fixed(int ddir, struct iov_iter *iter,
return 0;
}
+static inline struct io_rsrc_node *io_find_buf_node(struct io_kiocb *req,
+ unsigned issue_flags)
+{
+ struct io_ring_ctx *ctx = req->ctx;
+ struct io_rsrc_node *node;
+
+ if (req->buf_node)
Seems it should be checking for REQ_F_BUF_NODE instead
+ return req->buf_node;
+
+ io_ring_submit_lock(ctx, issue_flags);
+ node = io_rsrc_node_lookup(&ctx->buf_table, req->buf_index);
+ if (node)
+ io_req_assign_buf_node(req, node);
+ io_ring_submit_unlock(ctx, issue_flags);
+ return node;
+}
--
Pavel Begunkov
