NFSD: Add instructions on how to deal with xdrgen files

xdrgen requires a number of Python packages on the build system. We
don't want to add these to the kernel build dependency list, which
is long enough already.

The generated files are generated manually using

  $ cd fs/nfsd && make xdrgen

whenever the .x files are modified, then they are checked into the
kernel repo so others do not need to rebuild them.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
index 55744bb786c9a09ea47069f3643aaf92397c17a8..f0da4d69dc74ee0fd5e7ecf479031d51671504cd 100644 (file)
--- a/fs/nfsd/Makefile
+++ b/fs/nfsd/Makefile
@@ -26,7 +26,15 @@ nfsd-$(CONFIG_NFSD_FLEXFILELAYOUT) += flexfilelayout.o flexfilelayoutxdr.o
 nfsd-$(CONFIG_NFS_LOCALIO) += localio.o
 nfsd-$(CONFIG_DEBUG_FS) += debugfs.o
 
-
+#
+# XDR code generation (requires Python and additional packages)
+#
+# The generated *xdr_gen.{h,c} files are checked into git. Normal kernel
+# builds do not require the xdrgen tool or its Python dependencies.
+#
+# Developers modifying .x files in Documentation/sunrpc/xdr/ should run
+# "make xdrgen" to regenerate the affected files.
+#
 .PHONY: xdrgen
 
 xdrgen: ../../include/linux/sunrpc/xdrgen/nfs4_1.h nfs4xdr_gen.h nfs4xdr_gen.c