[v9,07/10] modpost: Add -b option for emitting built-in aliases

Message ID 20221219204619.2205248-8-allenwebb@google.com
State New
Headers
Series Generate modules.builtin.alias from match ids |

Commit Message

Allen Webb Dec. 19, 2022, 8:46 p.m. UTC
  This adds an unimplemented command line flag for writing the built-in
aliases to a file.

Signed-off-by: Allen Webb <allenwebb@google.com>
---
 scripts/mod/modpost.c | 23 +++++++++++++++++++++--
 scripts/mod/modpost.h |  1 +
 2 files changed, 22 insertions(+), 2 deletions(-)
  

Comments

Greg KH Dec. 20, 2022, 6:43 a.m. UTC | #1
On Mon, Dec 19, 2022 at 02:46:15PM -0600, Allen Webb wrote:
> This adds an unimplemented command line flag for writing the built-in
> aliases to a file.

If it is unimplemented, why add it?

And this needs a lot more description as to why you are changing this
here, as well as documentation for the flag you added, right?

thanks,

greg k-h
  
Allen Webb Dec. 20, 2022, 5:32 p.m. UTC | #2
On Tue, Dec 20, 2022 at 12:43 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Mon, Dec 19, 2022 at 02:46:15PM -0600, Allen Webb wrote:
> > This adds an unimplemented command line flag for writing the built-in
> > aliases to a file.
>
> If it is unimplemented, why add it?

This is a fairly self contained change even though the code that
populates mod->modalias_buf is in the next patch. I could flatten the
two commits, but I was trying to keep this to a single logical change.
There is somewhat of a chicken and egg problem here. If the other
patch comes first it will be dead code, if this comes first it is
pretty much dead code.

>
> And this needs a lot more description as to why you are changing this
> here, as well as documentation for the flag you added, right?

I might be missing something, but I don't see an obvious place where
the other command line parameters for modpost are documented, so I
will add a comment inside the case statement unless you have a better
idea.

>
> thanks,
>
> greg k-h
  

Patch

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 2c80da0220c3..e38d6b2ceea4 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2165,6 +2165,19 @@  static void write_if_changed(struct buffer *b, const char *fname)
 	write_buf(b, fname);
 }
 
+/* Write the builtin aliases to the specified file. */
+static void write_builtin(const char *fname)
+{
+	struct buffer buf = { };
+	struct module *mod;
+
+	list_for_each_entry(mod, &modules, list)
+		buf_write(&buf, mod->modalias_buf.p, mod->modalias_buf.pos);
+
+	write_if_changed(&buf, fname);
+	free(buf.p);
+}
+
 static void write_vmlinux_export_c_file(struct module *mod)
 {
 	struct buffer buf = { };
@@ -2321,13 +2334,16 @@  int main(int argc, char **argv)
 {
 	struct module *mod;
 	char *missing_namespace_deps = NULL;
-	char *dump_write = NULL, *files_source = NULL;
+	char *builtin_write = NULL, *dump_write = NULL, *files_source = NULL;
 	int opt;
 	LIST_HEAD(dump_lists);
 	struct dump_list *dl, *dl2;
 
-	while ((opt = getopt(argc, argv, "ei:mnT:o:awENd:")) != -1) {
+	while ((opt = getopt(argc, argv, "b:ei:mnT:o:awENd:")) != -1) {
 		switch (opt) {
+		case 'b':
+			builtin_write = optarg;
+			break;
 		case 'e':
 			external_module = true;
 			break;
@@ -2390,6 +2406,9 @@  int main(int argc, char **argv)
 			write_mod_c_file(mod);
 	}
 
+	if (builtin_write)
+		write_builtin(builtin_write);
+
 	if (missing_namespace_deps)
 		write_namespace_deps_files(missing_namespace_deps);
 
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 34fe5fc0b02c..c55a6aeb46bf 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -123,6 +123,7 @@  struct module {
 	bool has_init;
 	bool has_cleanup;
 	struct buffer dev_table_buf;
+	struct buffer modalias_buf;
 	char	     srcversion[25];
 	// Missing namespace dependencies
 	struct list_head missing_namespaces;