From: Masahiro Yamada <masahiroy@kernel.org> To: linux-kbuild@vger.kernel.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>, Ard Biesheuvel <ardb@kernel.org>, Nicolas Pitre <npitre@baylibre.com>, Masahiro Yamada <masahiroy@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Michal Marek <michal.lkml@markovi.net> Subject: [PATCH v3 6/8] modpost: use null string instead of NULL pointer for default namespace Date: Wed, 28 Sep 2022 15:39:45 +0900 [thread overview] Message-ID: <20220928063947.299333-7-masahiroy@kernel.org> (raw) In-Reply-To: <20220928063947.299333-1-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. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> --- (no changes since v1) 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 0bb5bbd176b4..29f30558a398 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -297,6 +297,13 @@ 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; @@ -366,7 +373,7 @@ 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); @@ -1928,8 +1935,7 @@ 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); @@ -2015,8 +2021,7 @@ 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; @@ -2284,7 +2289,7 @@ 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); -- 2.34.1
WARNING: multiple messages have this Message-ID (diff)
From: Masahiro Yamada <masahiroy@kernel.org> To: linux-kbuild@vger.kernel.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>, Ard Biesheuvel <ardb@kernel.org>, Nicolas Pitre <npitre@baylibre.com>, Masahiro Yamada <masahiroy@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Michal Marek <michal.lkml@markovi.net> Subject: [PATCH v3 6/8] modpost: use null string instead of NULL pointer for default namespace Date: Wed, 28 Sep 2022 06:39:45 +0000 [thread overview] Message-ID: <20220928063947.299333-7-masahiroy@kernel.org> (raw) In-Reply-To: <20220928063947.299333-1-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. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> --- (no changes since v1) 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 0bb5bbd176b4..29f30558a398 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -297,6 +297,13 @@ 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; @@ -366,7 +373,7 @@ 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); @@ -1928,8 +1935,7 @@ 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); @@ -2015,8 +2021,7 @@ 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; @@ -2284,7 +2289,7 @@ 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); -- 2.34.1
next prev parent reply other threads:[~2022-09-28 6:43 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-28 6:39 [PATCH v3 0/8] Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TRIM_UNUSED_KSYMS Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 0/8] Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TRIM_U Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 1/8] kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 2/8] kbuild: rebuild .vmlinux.export.o when its prerequisite is updated Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada 2022-10-09 1:19 ` [kbuild] b3830bad81: System_halted kernel test robot 2022-10-09 1:19 ` kernel test robot 2022-10-10 19:29 ` Masahiro Yamada 2022-10-10 19:29 ` Masahiro Yamada 2022-10-10 19:29 ` Masahiro Yamada 2022-10-11 9:36 ` Yujie Liu 2022-10-11 9:36 ` Yujie Liu 2022-10-11 9:36 ` Yujie Liu 2022-10-11 14:42 ` Masahiro Yamada 2022-10-11 14:42 ` Masahiro Yamada 2022-10-11 14:42 ` Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 3/8] kbuild: generate KSYMTAB entries by modpost Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada 2022-09-28 19:29 ` Masahiro Yamada 2022-09-28 19:29 ` Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 4/8] ia64,export.h: replace EXPORT_DATA_SYMBOL* with EXPORT_SYMBOL* Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 5/8] modpost: squash sym_update_namespace() into sym_add_exported() Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada [this message] 2022-09-28 6:39 ` [PATCH v3 6/8] modpost: use null string instead of NULL pointer for default namespace Masahiro Yamada 2022-09-28 9:53 ` David Laight 2022-09-28 13:52 ` Masahiro Yamada 2022-09-28 13:52 ` Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 7/8] modpost: squash report_sec_mismatch() and remove enum mismatch Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada 2022-09-28 6:39 ` [PATCH v3 8/8] kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion Masahiro Yamada 2022-09-28 6:39 ` Masahiro Yamada 2022-09-28 21:04 ` [PATCH v3 0/8] Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TRIM_UNUSED_KSYMS Masahiro Yamada 2022-09-28 21:04 ` [PATCH v3 0/8] Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TR Masahiro Yamada
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20220928063947.299333-7-masahiroy@kernel.org \ --to=masahiroy@kernel.org \ --cc=ardb@kernel.org \ --cc=linux-arch@vger.kernel.org \ --cc=linux-ia64@vger.kernel.org \ --cc=linux-kbuild@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=michal.lkml@markovi.net \ --cc=ndesaulniers@google.com \ --cc=npitre@baylibre.com \ --cc=viro@zeniv.linux.org.uk \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.