From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nicolas Schier <nicolas@fjasle.eu>,
Masahiro Yamada <masahiroy@kernel.org>
Subject: [PATCH v6 14/20] modpost: use null string instead of NULL pointer for default namespace
Date: Mon, 22 May 2023 01:04:19 +0900 [thread overview]
Message-ID: <20230521160426.1881124-15-masahiroy@kernel.org> (raw)
In-Reply-To: <20230521160426.1881124-1-masahiroy@kernel.org>
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.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
scripts/mod/modpost.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 8fe2aa7bf71b..f14fe9301ae6 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -298,6 +298,13 @@ 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;
@@ -367,7 +374,7 @@ 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);
@@ -1775,8 +1782,7 @@ 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);
@@ -1862,8 +1868,7 @@ 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;
@@ -2131,7 +2136,7 @@ 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);
--
2.39.2
next prev parent reply other threads:[~2023-05-21 16:06 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-21 16:04 [PATCH v6 00/20] Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TRIM_UNUSED_KSYMS Masahiro Yamada
2023-05-21 16:04 ` [PATCH v6 01/20] Revert "modpost: skip ELF local symbols during section mismatch check" Masahiro Yamada
2023-05-22 17:42 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 02/20] modpost: fix section mismatch message for R_ARM_ABS32 Masahiro Yamada
2023-05-22 17:56 ` Nick Desaulniers
2023-05-22 21:35 ` Ard Biesheuvel
2023-05-23 5:07 ` Masahiro Yamada
2023-05-23 7:13 ` Ard Biesheuvel
2023-05-21 16:04 ` [PATCH v6 03/20] modpost: detect section mismatch for R_ARM_MOVW_ABS_NC and R_ARM_MOVT_ABS Masahiro Yamada
2023-05-22 18:03 ` Nick Desaulniers
2023-05-22 21:50 ` Ard Biesheuvel
2023-05-23 11:58 ` Masahiro Yamada
2023-05-23 12:20 ` Ard Biesheuvel
2023-05-24 0:02 ` Masahiro Yamada
2023-05-24 0:04 ` Masahiro Yamada
2023-05-21 16:04 ` [PATCH v6 04/20] modpost: remove unused argument from secref_whitelist() Masahiro Yamada
2023-05-22 18:10 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 05/20] modpost: refactor find_fromsym() and find_tosym() Masahiro Yamada
2023-05-22 18:18 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 06/20] modpost: unify 'sym' and 'to' in default_mismatch_handler() Masahiro Yamada
2023-05-22 18:23 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 07/20] modpost: replace r->r_offset, r->r_addend with faddr, taddr Masahiro Yamada
2023-05-22 18:31 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 08/20] modpost: remove is_shndx_special() check from section_rel(a) Masahiro Yamada
2023-05-25 17:20 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 09/20] modpost: pass struct module pointer to check_section_mismatch() Masahiro Yamada
2023-05-25 17:23 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 10/20] kbuild: generate KSYMTAB entries by modpost Masahiro Yamada
2023-05-25 17:50 ` Nick Desaulniers
2023-06-02 13:51 ` Masahiro Yamada
2023-05-21 16:04 ` [PATCH v6 11/20] ia64,export.h: replace EXPORT_DATA_SYMBOL* with EXPORT_SYMBOL* Masahiro Yamada
2023-05-25 17:52 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 12/20] modpost: check static EXPORT_SYMBOL* by modpost again Masahiro Yamada
2023-05-25 18:18 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 13/20] modpost: squash sym_update_namespace() into sym_add_exported() Masahiro Yamada
2023-05-21 16:04 ` Masahiro Yamada [this message]
2023-05-21 16:04 ` [PATCH v6 15/20] kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion Masahiro Yamada
2023-05-25 18:14 ` Nick Desaulniers
2023-05-28 7:40 ` Masahiro Yamada
2023-05-21 16:04 ` [PATCH v6 16/20] modpost: merge fromsec=DATA_SECTIONS entries in sectioncheck table Masahiro Yamada
2023-05-25 18:30 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 17/20] modpost: merge bad_tosec=ALL_EXIT_SECTIONS " Masahiro Yamada
2023-05-25 18:36 ` Nick Desaulniers
2023-05-28 16:43 ` Masahiro Yamada
2023-05-21 16:04 ` [PATCH v6 18/20] modpost: remove *_sections[] arrays Masahiro Yamada
2023-05-21 16:04 ` [PATCH v6 19/20] modpost: merge two similar section mismatch warnings Masahiro Yamada
2023-05-25 18:20 ` Nick Desaulniers
2023-05-21 16:04 ` [PATCH v6 20/20] modpost: show offset from symbol for " Masahiro Yamada
2023-05-25 18:26 ` Nick Desaulniers
2023-05-28 7:29 ` Masahiro Yamada
2023-05-22 1:47 ` [PATCH v6 00/20] Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TRIM_UNUSED_KSYMS Masahiro Yamada
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