X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=Documentation%2Ffilesystems%2Frelay.txt;h=510b722667ac885cf7abed3732961941a5ad1c14;hb=bbba75606963c82febf7bd2761ea848ac5d1a1bb;hp=094f2d2f38b1a5571283ee745aa494c12b12808c;hpb=a8e98d6d51a3eb7bb061b1625193a129c8bd094f;p=mv-sheeva.git

diff --git a/Documentation/filesystems/relay.txt b/Documentation/filesystems/relay.txt
index 094f2d2f38b..510b722667a 100644
--- a/Documentation/filesystems/relay.txt
+++ b/Documentation/filesystems/relay.txt
@@ -294,6 +294,16 @@ user-defined data with a channel, and is immediately available
 (including in create_buf_file()) via chan->private_data or
 buf->chan->private_data.
 
+Buffer-only channels
+--------------------
+
+These channels have no files associated and can be created with
+relay_open(NULL, NULL, ...). Such channels are useful in scenarios such
+as when doing early tracing in the kernel, before the VFS is up. In these
+cases, one may open a buffer-only channel and then call
+relay_late_setup_files() when the kernel is ready to handle files,
+to expose the buffered data to the userspace.
+
 Channel 'modes'
 ---------------