| Message ID | 20220610183236.1272216-8-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL() | expand |
On Fri, Jun 10, 2022 at 11:34 AM Masahiro Yamada <masahiroy@kernel.org> wrote: > > 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> Sorry for the late review. If this is still useful: Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Feel free to ping me via mail if I'm falling behind. Otherwise you should join us on IRC. (#clangbuiltlinux on libera) > --- > > scripts/mod/modpost.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c > index 0db2cbb74a2a..5a1785645943 100644 > --- a/scripts/mod/modpost.c > +++ b/scripts/mod/modpost.c > @@ -296,6 +296,13 @@ 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; > @@ -371,7 +378,7 @@ 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); > > @@ -2117,8 +2124,7 @@ 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); > @@ -2201,7 +2207,7 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) > list_for_each_entry(sym, &mod->exported_symbols, list) > buf_printf(buf, "KSYMTAB_ENTRY(%s, \"%s\", \"%s\");\n", > sym->name, sym->is_gpl_only ? "_gpl" : "", > - sym->namespace ?: ""); > + sym->namespace); > > if (!modversions) > return; > @@ -2471,7 +2477,7 @@ 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); > -- > 2.32.0 >
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 0db2cbb74a2a..5a1785645943 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -296,6 +296,13 @@ 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; @@ -371,7 +378,7 @@ 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); @@ -2117,8 +2124,7 @@ 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); @@ -2201,7 +2207,7 @@ static void add_exported_symbols(struct buffer *buf, struct module *mod) list_for_each_entry(sym, &mod->exported_symbols, list) buf_printf(buf, "KSYMTAB_ENTRY(%s, \"%s\", \"%s\");\n", sym->name, sym->is_gpl_only ? "_gpl" : "", - sym->namespace ?: ""); + sym->namespace); if (!modversions) return; @@ -2471,7 +2477,7 @@ 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);
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> --- scripts/mod/modpost.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)