Re: [PATCH v3 08/13] io_uring: implement fixed buffers registration similar to fixed files

[Bijan Mottahedeh <bijan.mottahedeh@xxxxxxxxxx>]

> Forgot to mention, I failed to find where you do
> io_set_resource_node() in v4 for fixed reads/writes.
> Also, it should be done during submission, io_prep_rw()
> is the right place for that.

Would something like below be ok?  I renamed io_set_resource_node() to 
io_get_fixed_rsrc_ref() to make its function more clear and also 
distinguish it from io_sqe_rsrc_set_node().



diff --git a/fs/io_uring.c b/fs/io_uring.c
index bd55d11..a9b9881 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1083,12 +1083,11 @@ static inline void io_clean_op(struct io_kiocb *req)
                __io_clean_op(req);
 }

-static inline void io_set_resource_node(struct io_kiocb *req)
+static inline void io_get_fixed_rsrc_ref(struct io_kiocb *req,
+                                        struct fixed_rsrc_data *rsrc_data)
 {
-       struct io_ring_ctx *ctx = req->ctx;
-
        if (!req->fixed_rsrc_refs) {
-               req->fixed_rsrc_refs = &ctx->file_data->node->refs;
+               req->fixed_rsrc_refs = &rsrc_data->node->refs;
                percpu_ref_get(req->fixed_rsrc_refs);
        }
 }
@@ -2928,6 +2927,9 @@ static int io_prep_rw(struct io_kiocb *req, const 
struct i
        req->rw.addr = READ_ONCE(sqe->addr);
        req->rw.len = READ_ONCE(sqe->len);
        req->buf_index = READ_ONCE(sqe->buf_index);
+       if (req->opcode == IORING_OP_READ_FIXED ||
+           req->opcode == IORING_OP_WRITE_FIXED)
+               io_get_fixed_rsrc_ref(req, ctx->buf_data);
        return 0;
 }

@@ -6452,7 +6454,7 @@ static struct file *io_file_get(struct 
io_submit_state *st
                        return NULL;
                fd = array_index_nospec(fd, ctx->nr_user_files);
                file = io_file_from_index(ctx, fd);
-               io_set_resource_node(req);
+               io_get_fixed_rsrc_ref(req, ctx->file_data);
        } else {
                trace_io_uring_file_get(ctx, fd);
                file = __io_file_get(state, fd);