fs: add a write stream field to the kiocb

Prepare for io_uring passthrough of write streams.

The write stream field in the kiocb structure fits into an existing
2-byte hole, so its size is not changed.

Based on a patch from Keith Busch <kbusch@kernel.org>

Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4b5cad44a12683df3fd2e7cd4fcd74e4b63be155..1997be247b6c6a266f30f92e3be888562ae7d02a 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -370,6 +370,7 @@ struct kiocb {
        void                    *private;
        int                     ki_flags;
        u16                     ki_ioprio; /* See linux/ioprio.h */
+       u8                      ki_write_stream;
        union {
                /*
                 * Only used for async buffered reads, where it denotes the