1 files changed, 67 insertions, 27 deletions

diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
index b90aca3a57fa..36aadfe5ac00 100644
--- a/io_uring/kbuf.h
+++ b/io_uring/kbuf.h
@@ -4,6 +4,16 @@
 
 #include <uapi/linux/io_uring.h>
 
+enum {
+	/* ring mapped provided buffers */
+	IOBL_BUF_RING	= 1,
+	/* ring mapped provided buffers, but mmap'ed by application */
+	IOBL_MMAP	= 2,
+	/* buffers are consumed incrementally rather than always fully */
+	IOBL_INC	= 4,
+
+};
+
 struct io_buffer_list {
 	/*
 	 * If ->buf_nr_pages is set, then buf_pages/buf_ring are used. If not,
@@ -25,12 +35,9 @@ struct io_buffer_list {
 	__u16 head;
 	__u16 mask;
 
-	atomic_t refs;
+	__u16 flags;
 
-	/* ring mapped provided buffers */
-	__u8 is_buf_ring;
-	/* ring mapped provided buffers, but mmap'ed by application */
-	__u8 is_mmap;
+	atomic_t refs;
 };
 
 struct io_buffer {
@@ -52,8 +59,8 @@ struct buf_sel_arg {
 	struct iovec *iovs;
 	size_t out_len;
 	size_t max_len;
-	int nr_iovs;
-	int mode;
+	unsigned short nr_iovs;
+	unsigned short mode;
 };
 
 void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
@@ -73,7 +80,7 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
 int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
 int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg);
 
-void __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags);
+void __io_put_kbuf(struct io_kiocb *req, int len, unsigned issue_flags);
 
 bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
 
@@ -117,25 +124,55 @@ static inline bool io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
 	return false;
 }
 
-static inline void __io_put_kbuf_ring(struct io_kiocb *req, int nr)
+/* Mapped buffer ring, return io_uring_buf from head */
+#define io_ring_head_to_buf(br, head, mask)	&(br)->bufs[(head) & (mask)]
+
+static inline 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 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) {
-		if (req->flags & REQ_F_BUFFERS_COMMIT) {
-			bl->head += nr;
-			req->flags &= ~REQ_F_BUFFERS_COMMIT;
-		}
+		ret = io_kbuf_commit(req, bl, len, nr);
 		req->buf_index = bl->bgid;
 	}
 	req->flags &= ~REQ_F_BUFFER_RING;
+	return ret;
 }
 
-static inline void __io_put_kbuf_list(struct io_kiocb *req,
+static inline void __io_put_kbuf_list(struct io_kiocb *req, int len,
 				      struct list_head *list)
 {
 	if (req->flags & REQ_F_BUFFER_RING) {
-		__io_put_kbuf_ring(req, 1);
+		__io_put_kbuf_ring(req, len, 1);
 	} else {
 		req->buf_index = req->kbuf->bgid;
 		list_add(&req->kbuf->list, list);
@@ -150,11 +187,12 @@ static inline void io_kbuf_drop(struct io_kiocb *req)
 	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
 		return;
 
-	__io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
+	/* len == 0 is fine here, non-ring will always drop all of it */
+	__io_put_kbuf_list(req, 0, &req->ctx->io_buffers_comp);
 }
 
-static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int nbufs,
-					  unsigned issue_flags)
+static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int len,
+					  int nbufs, unsigned issue_flags)
 {
 	unsigned int ret;
 
@@ -162,22 +200,24 @@ static inline unsigned int __io_put_kbufs(struct io_kiocb *req, int nbufs,
 		return 0;
 
 	ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
-	if (req->flags & REQ_F_BUFFER_RING)
-		__io_put_kbuf_ring(req, nbufs);
-	else
-		__io_put_kbuf(req, issue_flags);
+	if (req->flags & REQ_F_BUFFER_RING) {
+		if (!__io_put_kbuf_ring(req, len, nbufs))
+			ret |= IORING_CQE_F_BUF_MORE;
+	} else {
+		__io_put_kbuf(req, len, issue_flags);
+	}
 	return ret;
 }
 
-static inline unsigned int io_put_kbuf(struct io_kiocb *req,
+static inline unsigned int io_put_kbuf(struct io_kiocb *req, int len,
 				       unsigned issue_flags)
 {
-	return __io_put_kbufs(req, 1, issue_flags);
+	return __io_put_kbufs(req, len, 1, issue_flags);
 }
 
-static inline unsigned int io_put_kbufs(struct io_kiocb *req, int nbufs,
-					unsigned issue_flags)
+static inline unsigned int io_put_kbufs(struct io_kiocb *req, int len,
+					int nbufs, unsigned issue_flags)
 {
-	return __io_put_kbufs(req, nbufs, issue_flags);
+	return __io_put_kbufs(req, len, nbufs, issue_flags);
 }
 #endif