modpost: dump missing namespaces into a single modules.nsdeps file

The modpost, with the -d option given, generates per-module .ns_deps
files.

Kbuild generates per-module .mod files to carry module information.
This is convenient because Make handles multiple jobs in parallel
when the -j option is given.

On the other hand, the modpost always runs as a single thread.
I do not see a strong reason to produce separate .ns_deps files.

This commit changes the modpost to generate just one file,
modules.nsdeps, each line of which has the following format:

  <module_name>: <list of missing namespaces>

Please note it contains *missing* namespaces instead of required ones.
So, modules.nsdeps is empty if the namespace dependency is all good.

This will work more efficiently because spatch will no longer process
already imported namespaces. I removed the '(if needed)' from the
nsdeps log since spatch is invoked only when needed.

This also solves the stale .ns_deps problem reported by Jessica Yu:

  https://lkml.org/lkml/2019/10/28/467

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Matthias Maennich <maennich@google.com>
Tested-by: Matthias Maennich <maennich@google.com>

1 files changed, 10 insertions, 11 deletions

diff --git a/scripts/nsdeps b/scripts/nsdeps
index 04cea0921673..f802c6f7b860 100644
--- a/scripts/nsdeps
+++ b/scripts/nsdeps
@@ -27,15 +27,14 @@ generate_deps_for_ns() {
 }
 
 generate_deps() {
-	local mod_name=`basename $@ .ko`
-	local mod_file=`echo $@ | sed -e 's/\.ko/\.mod/'`
-	local ns_deps_file=`echo $@ | sed -e 's/\.ko/\.ns_deps/'`
-	if [ ! -f "$ns_deps_file" ]; then return; fi
-	local mod_source_files="`cat $mod_file | sed -n 1p                      \
+	local mod=${1%.ko:}
+	shift
+	local namespaces="$*"
+	local mod_source_files="`cat $mod.mod | sed -n 1p                      \
 					      | sed -e 's/\.o/\.c/g'           \
 					      | sed "s|[^ ]* *|${srctree}/&|g"`"
-	for ns in `cat $ns_deps_file`; do
-		echo "Adding namespace $ns to module $mod_name (if needed)."
+	for ns in $namespaces; do
+		echo "Adding namespace $ns to module $mod.ko."
 		generate_deps_for_ns $ns "$mod_source_files"
 		# sort the imports
 		for source_file in $mod_source_files; do
@@ -52,7 +51,7 @@ generate_deps() {
 	done
 }
 
-for f in `cat $objtree/modules.order`; do
-	generate_deps $f
-done
-
+while read line
+do
+	generate_deps $line
+done < modules.nsdeps