[PATCH v2 02/26] modpost: change mod->gpl_compatible to bool type

Masahiro Yamada
2022-05-01T08:43:13Z

Currently, mod->gpl_compatible is tristate; it is set to -1 by default,
then to 1 or 0 when MODULE_LICENSE() is found.

Maybe, -1 was chosen to represent the 'unknown' license, but it is not
useful.

The current code:

if (!mod->gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);

... only cares whether gpl_compatible is zero or not.

Change it to a bool type with the initial value 'true', which has no
functional change.

The default value should be 'true' instead of 'false'.

Since commit 1d6cd3929360 ("modpost: turn missing MODULE_LICENSE() into
error"), unknown module license is an error.

The error message, "missing MODULE_LICENSE()" is enough to explain the
issue. It is not sensible to show another message, "GPL-incompatible
module ... uses GPL-only symbol".

Add comments to explain this.

While I was here, I renamed gpl_compatible to is_gpl_compatible for
clarification, and also slightly refactored the code.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

Changes in v2:
- Split as a separate commit
- More code refactoring
- Add a comment
- Rename it to ->is_gpl_compatible (Nick)

scripts/mod/modpost.c | 17 +++++++++++------
scripts/mod/modpost.h | 2 +-
2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index a6035ab78cd8..f2d6c152cd3f 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -187,7 +187,14 @@ static struct module *new_module(const char *modname)
/* add to list */
strcpy(mod->name, modname);
mod->is_vmlinux = (strcmp(modname, "vmlinux") == 0);
- mod->gpl_compatible = -1;
+
+ /*
+ * Set mod->is_gpl_compatible to true by default to skip
+ * check_for_gpl_usage() when MODULE_LICENSE() is missing.
+ * If it is the case, modpost will exit with error anyway.
+ */
+ mod->is_gpl_compatible = true;
+
mod->next = modules;
modules = mod;

@@ -2012,10 +2019,8 @@ static void read_symbols(const char *modname)
if (!license)
error("missing MODULE_LICENSE() in %s\n", modname);
while (license) {
- if (license_is_gpl_compatible(license))
- mod->gpl_compatible = 1;
- else {
- mod->gpl_compatible = 0;
+ if (!license_is_gpl_compatible(license)) {
+ mod->is_gpl_compatible = false;
break;
}
license = get_next_modinfo(&info, "license", license);
@@ -2183,7 +2188,7 @@ static void check_exports(struct module *mod)
add_namespace(&mod->missing_namespaces, exp->namespace);
}

- if (!mod->gpl_compatible)
+ if (!mod->is_gpl_compatible)
check_for_gpl_usage(exp->export, basename, exp->name);
}
}
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 7ccfcc8899c1..f21a3782885b 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -110,7 +110,7 @@ buf_write(struct buffer *buf, const char *s, int len);

struct module {
struct module *next;
- int gpl_compatible;
+ bool is_gpl_compatible;
struct symbol *unres;
bool from_dump; /* true if module was loaded from *.symvers */
bool is_vmlinux;
--
2.32.0