ublk: add helper ublk_check_fetch_buf()

Add helper ublk_check_fetch_buf() for checking buffer only.

Signed-off-by: Ming Lei <[email protected]>

Author: Ming Lei

drivers/block/ublk_drv.c

@@ -2165,6 +2165,22 @@ static int ublk_unregister_io_buf(struct io_uring_cmd *cmd,
 	return io_buffer_unregister_bvec(cmd, index, issue_flags);
 }
 
+static int ublk_check_fetch_buf(const struct ublk_queue *ubq, __u64 buf_addr)
+{
+	if (ublk_need_map_io(ubq)) {
+		/*
+		 * FETCH_RQ has to provide IO buffer if NEED GET
+		 * DATA is not enabled
+		 */
+		if (!buf_addr && !ublk_need_get_data(ubq))
+			return -EINVAL;
+	} else if (buf_addr) {
+		/* User copy requires addr to be unset */
+		return -EINVAL;
+	}
+	return 0;
+}
+
 static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
 		      struct ublk_io *io, __u64 buf_addr)
 {
@@ -2191,19 +2207,6 @@ static int ublk_fetch(struct io_uring_cmd *cmd, struct ublk_queue *ubq,
 
 	WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV);
 
-	if (ublk_need_map_io(ubq)) {
-		/*
-		 * FETCH_RQ has to provide IO buffer if NEED GET
-		 * DATA is not enabled
-		 */
-		if (!buf_addr && !ublk_need_get_data(ubq))
-			goto out;
-	} else if (buf_addr) {
-		/* User copy requires addr to be unset */
-		ret = -EINVAL;
-		goto out;
-	}
-
 	ublk_fill_io_cmd(io, cmd, 0);
 	ret = ublk_config_io_buf(ubq, io, cmd, buf_addr, NULL);
 	if (ret)
@@ -2316,6 +2319,9 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
 	io = &ubq->ios[tag];
 	/* UBLK_IO_FETCH_REQ can be handled on any task, which sets io->task */
 	if (unlikely(_IOC_NR(cmd_op) == UBLK_IO_FETCH_REQ)) {
+		ret = ublk_check_fetch_buf(ubq, ub_cmd->addr);
+		if (ret)
+			goto out;
 		ret = ublk_fetch(cmd, ubq, io, ub_cmd->addr);
 		if (ret)
 			goto out;