linux-kernel - [PATCH v2 06/10] modpost: remove annoying namespace_from

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Message-Id: <20220405140229.2895394-7-masahiroy@kernel.org>
Date:   Tue,  5 Apr 2022 23:02:25 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     linux-kbuild@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Masahiro Yamada <masahiroy@...nel.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: [PATCH v2 06/10] modpost: remove annoying namespace_from_kstrtabns()

There are two call sites for sym_update_namespace().

When the symbol has no namespace, s->namespace is set to NULL,
but the conversion from "" to NULL is done in two different places.

[1] read_symbols()

  This gets the namespace from __kstrtabns_<symbol>. If the symbol has
  no namespace, sym_get_data(info, sym) returns the empty string "".
  namespace_from_kstrtabns() converts it to NULL before it is passed to
  sym_update_namespace().

[2] read_dump()

  This gets the namespace from the dump file, *.symvers. If the symbol
  has no namespace, the 'namespace' is the empty string "", which is
  directly passed into sym_update_namespace(). The conversion from
  "" to NULL is done in sym_update_namespace().

namespace_from_kstrtabns() exists only for creating this inconsistency.

By removing it, sym_update_namespace() is consistently passed with ""
when the symbol has no namespace.

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

Changes in v2:
  - new

 scripts/mod/modpost.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 2a202764ff48..522d5249d196 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -369,13 +369,6 @@ static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 		return export_unknown;
 }
 
-static const char *namespace_from_kstrtabns(const struct elf_info *info,
-					    const Elf_Sym *sym)
-{
-	const char *value = sym_get_data(info, sym);
-	return value[0] ? value : NULL;
-}
-
 static void sym_update_namespace(const char *symname, const char *namespace)
 {
 	struct symbol *s = find_symbol(symname);
@@ -391,8 +384,7 @@ static void sym_update_namespace(const char *symname, const char *namespace)
 	}
 
 	free(s->namespace);
-	s->namespace =
-		namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
+	s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
 }
 
 /**
@@ -2049,9 +2041,7 @@ static void read_symbols(const char *modname)
 		/* Apply symbol namespaces from __kstrtabns_<symbol> entries. */
 		if (strstarts(symname, "__kstrtabns_"))
 			sym_update_namespace(symname + strlen("__kstrtabns_"),
-					     namespace_from_kstrtabns(&info,
-								      sym));
-
+					     sym_get_data(&info, sym));
 		if (strstarts(symname, "__crc_"))
 			handle_modversion(mod, &info, sym,
 					  symname + strlen("__crc_"));
-- 
2.32.0