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author | Masahiro Yamada <masahiroy@kernel.org> | 2023-06-11 18:50:56 +0300 |
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committer | Masahiro Yamada <masahiroy@kernel.org> | 2023-06-22 15:21:06 +0300 |
commit | 700c48b439921b67715e25380e0f67e6e490d7b8 (patch) | |
tree | e78ec4cda73a6324761c9f6f5da089e6cf33e7a6 /scripts/mod/modpost.c | |
parent | 6e7611c485315a0e4e36c763d0810677e1f26ecd (diff) | |
download | linux-700c48b439921b67715e25380e0f67e6e490d7b8.tar.xz |
modpost: use null string instead of NULL pointer for default namespace
The default namespace is the null string, "".
When set, the null string "" is converted to NULL:
s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL;
When printed, the NULL pointer is get back to the null string:
sym->namespace ?: ""
This saves 1 byte memory allocated for "", but loses the readability.
In kernel-space, we strive to save memory, but modpost is a userspace
tool used to build the kernel. On modern systems, such small piece of
memory is not a big deal.
Handle the namespace string as is.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Diffstat (limited to 'scripts/mod/modpost.c')
-rw-r--r-- | scripts/mod/modpost.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index bc9ef40ac620..a7c979b0ea21 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -300,6 +300,13 @@ static bool contains_namespace(struct list_head *head, const char *namespace) { struct namespace_list *list; + /* + * The default namespace is null string "", which is always implicitly + * contained. + */ + if (!namespace[0]) + return true; + list_for_each_entry(list, head, list) { if (!strcmp(list->namespace, namespace)) return true; @@ -369,7 +376,7 @@ static struct symbol *sym_add_exported(const char *name, struct module *mod, s = alloc_symbol(name); s->module = mod; s->is_gpl_only = gpl_only; - s->namespace = namespace[0] ? NOFAIL(strdup(namespace)) : NULL; + s->namespace = NOFAIL(strdup(namespace)); list_add_tail(&s->list, &mod->exported_symbols); hash_add_symbol(s); @@ -1829,8 +1836,7 @@ static void check_exports(struct module *mod) else basename = mod->name; - if (exp->namespace && - !contains_namespace(&mod->imported_namespaces, exp->namespace)) { + if (!contains_namespace(&mod->imported_namespaces, exp->namespace)) { modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR, "module %s uses symbol %s from namespace %s, but does not import it.\n", basename, exp->name, exp->namespace); @@ -1916,8 +1922,7 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) list_for_each_entry(sym, &mod->exported_symbols, list) buf_printf(buf, "KSYMTAB_%s(%s, \"%s\", \"%s\");\n", sym->is_func ? "FUNC" : "DATA", sym->name, - sym->is_gpl_only ? "_gpl" : "", - sym->namespace ?: ""); + sym->is_gpl_only ? "_gpl" : "", sym->namespace); if (!modversions) return; @@ -2185,7 +2190,7 @@ static void write_dump(const char *fname) buf_printf(&buf, "0x%08x\t%s\t%s\tEXPORT_SYMBOL%s\t%s\n", sym->crc, sym->name, mod->name, sym->is_gpl_only ? "_GPL" : "", - sym->namespace ?: ""); + sym->namespace); } } write_buf(&buf, fname); |