linux-kernel - [PATCH 1/4] modpost: delegate updating namespaces to separate function

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Date:   Thu, 10 Oct 2019 16:14:40 +0100
From:   Matthias Maennich <maennich@...gle.com>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-team@...roid.com, maennich@...gle.com,
        Jessica Yu <jeyu@...nel.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Martijn Coenen <maco@...roid.com>,
        Lucas De Marchi <lucas.de.marchi@...il.com>,
        Shaun Ruffell <sruffell@...ffell.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Will Deacon <will@...nel.org>, linux-kbuild@...r.kernel.org,
        linux-modules@...r.kernel.org
Subject: [PATCH 1/4] modpost: delegate updating namespaces to separate function

Let the function 'sym_update_namespace' take care of updating the
namespace for a symbol. While this currently only replaces one single
location where namespaces are updated, in a following patch, this
function will get more call sites.

The function signature is intentionally close to sym_update_crc and
taking the name by char* seems like unnecessary work as the symbol has
to be looked up again. In a later patch of this series, this concern
will be addressed.

This function ensures that symbol::namespace is either NULL or has a
valid non-empty value. Previously, the empty string was considered 'no
namespace' as well and this lead to confusion.

Signed-off-by: Matthias Maennich <maennich@...gle.com>
---
 scripts/mod/modpost.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 4d2cdb4d71e3..9f5dcdff4d2f 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -362,6 +362,22 @@ static char *sym_extract_namespace(const char **symname)
 	return namespace;
 }
 
+static void sym_update_namespace(const char *symname, const char *namespace)
+{
+       struct symbol *s = find_symbol(symname);
+       /* That symbol should have been created earlier and thus this is
+        * actually an assertion. */
+       if (!s) {
+               merror("Could not update namespace(%s) for symbol %s\n",
+                      namespace, symname);
+               return;
+       }
+
+       free(s->namespace);
+       s->namespace =
+	       namespace && namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
+}
+
 /**
  * Add an exported symbol - it may have already been added without a
  * CRC, in this case just update the CRC
@@ -383,8 +399,7 @@ static struct symbol *sym_add_exported(const char *name, const char *namespace,
 			s->module = mod;
 		}
 	}
-	free(s->namespace);
-	s->namespace = namespace ? strdup(namespace) : NULL;
+	sym_update_namespace(name, namespace);
 	s->preloaded = 0;
 	s->vmlinux   = is_vmlinux(mod->name);
 	s->kernel    = 0;
@@ -2196,7 +2211,7 @@ static int check_exports(struct module *mod)
 		else
 			basename = mod->name;
 
-		if (exp->namespace && exp->namespace[0]) {
+		if (exp->namespace) {
 			add_namespace(&mod->required_namespaces,
 				      exp->namespace);
 
-- 
2.23.0.581.g78d2f28ef7-goog