1 files changed, 60 insertions, 0 deletions

diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 815fb58da3ba..3478be6d02ab 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -20,6 +20,9 @@
 /* BIDs are addressed by a 16-bit field in a CQE */
 #define MAX_BIDS_PER_BGID (1 << 16)
 
+/* Mapped buffer ring, return io_uring_buf from head */
+#define io_ring_head_to_buf(br, head, mask)	&(br)->bufs[(head) & (mask)]
+
 struct io_provide_buf {
 	struct file			*file;
 	__u64				addr;
@@ -29,6 +32,34 @@ struct io_provide_buf {
 	__u16				bid;
 };
 
+bool io_kbuf_commit(struct io_kiocb *req,
+		    struct io_buffer_list *bl, int len, int nr)
+{
+	if (unlikely(!(req->flags & REQ_F_BUFFERS_COMMIT)))
+		return true;
+
+	req->flags &= ~REQ_F_BUFFERS_COMMIT;
+
+	if (unlikely(len < 0))
+		return true;
+
+	if (bl->flags & IOBL_INC) {
+		struct io_uring_buf *buf;
+
+		buf = io_ring_head_to_buf(bl->buf_ring, bl->head, bl->mask);
+		if (WARN_ON_ONCE(len > buf->len))
+			len = buf->len;
+		buf->len -= len;
+		if (buf->len) {
+			buf->addr += len;
+			return false;
+		}
+	}
+
+	bl->head += nr;
+	return true;
+}
+
 static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx,
 							unsigned int bgid)
 {
@@ -323,6 +354,35 @@ int io_buffers_peek(struct io_kiocb *req, struct buf_sel_arg *arg)
 	return io_provided_buffers_select(req, &arg->max_len, bl, arg->iovs);
 }
 
+static inline bool __io_put_kbuf_ring(struct io_kiocb *req, int len, int nr)
+{
+	struct io_buffer_list *bl = req->buf_list;
+	bool ret = true;
+
+	if (bl) {
+		ret = io_kbuf_commit(req, bl, len, nr);
+		req->buf_index = bl->bgid;
+	}
+	req->flags &= ~REQ_F_BUFFER_RING;
+	return ret;
+}
+
+unsigned int __io_put_kbufs(struct io_kiocb *req, int len, int nbufs)
+{
+	unsigned int ret;
+
+	ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
+
+	if (unlikely(!(req->flags & REQ_F_BUFFER_RING))) {
+		io_kbuf_drop_legacy(req);
+		return ret;
+	}
+
+	if (!__io_put_kbuf_ring(req, len, nbufs))
+		ret |= IORING_CQE_F_BUF_MORE;
+	return ret;
+}
+
 static int __io_remove_buffers(struct io_ring_ctx *ctx,
 			       struct io_buffer_list *bl, unsigned nbufs)
 {