On Thu, Jun 25, 2015 at 5:18 PM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote: > Dan Streetman <ddstreet@xxxxxxxx> writes: >> Only include the built-in and per-module param_lock, and corresponding >> lock/unlock functions, if sysfs is enabled. If there is no sysfs there >> is no need for locking kernel params. >> >> This fixes a build break when CONFIG_SYSFS is not enabled, introduced >> by commit b51d23e. > > This doesn't even come close to applying to my tree? sorry, I had the !CONFIG_MODULES patch in my tree also, so this was on top of that one: https://lkml.org/lkml/2015/6/24/550 I can resend that one, on top of this one, or you can fix it up. Sorry for not getting it right the first time ;-) > > I've fixed it like so, and tested it compiles both with and without > SYSFS. > > Subject: param: fix module param locks when !CONFIG_SYSFS. > > As Dan Streetman points out, the entire point of locking for is to > stop sysfs accesses, so they're elided entirely in the !SYSFS case. > > Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> > > diff --git a/include/linux/module.h b/include/linux/module.h > index abaecf1a63df..237bce382e32 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -240,7 +240,9 @@ struct module { > unsigned int num_syms; > > /* Kernel parameters. */ > +#ifdef CONFIG_SYSFS > struct mutex param_lock; > +#endif > struct kernel_param *kp; > unsigned int num_kp; > > diff --git a/kernel/module.c b/kernel/module.c > index 1dcf09f214fa..c19b2c50b317 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -1820,6 +1820,10 @@ static void mod_sysfs_fini(struct module *mod) > mod_kobject_put(mod); > } > > +static void init_param_lock(struct module *mod) > +{ > + mutex_init(&mod->param_lock); > +} > #else /* !CONFIG_SYSFS */ > > static int mod_sysfs_setup(struct module *mod, > @@ -1842,6 +1846,9 @@ static void del_usage_links(struct module *mod) > { > } > > +static void init_param_lock(struct module *mod) > +{ > +} > #endif /* CONFIG_SYSFS */ > > static void mod_sysfs_teardown(struct module *mod) > @@ -3442,7 +3449,7 @@ static int load_module(struct load_info *info, const char __user *uargs, > if (err) > goto unlink_mod; > > - mutex_init(&mod->param_lock); > + init_param_lock(mod); oops, i missed fixing this up, when I tested with allnoconfig this wasn't built due to CONFIG_MODULES=n. I should have built only with syfs=n :( > > /* Now we've got everything in the final locations, we can > * find optional sections. */ > diff --git a/kernel/params.c b/kernel/params.c > index 8890d0b8dffc..faa461c16f12 100644 > --- a/kernel/params.c > +++ b/kernel/params.c > @@ -25,12 +25,22 @@ > #include <linux/slab.h> > #include <linux/ctype.h> > > +#ifdef CONFIG_SYSFS > /* Protects all built-in parameters, modules use their own param_lock */ > static DEFINE_MUTEX(param_lock); > > /* Use the module's mutex, or if built-in use the built-in mutex */ > #define KPARAM_MUTEX(mod) ((mod) ? &(mod)->param_lock : ¶m_lock) > -#define KPARAM_IS_LOCKED(mod) mutex_is_locked(KPARAM_MUTEX(mod)) > + > +static inline void check_kparam_locked(struct module *mod) > +{ > + BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod))); > +} > +#else > +static inline void check_kparam_locked(struct module *mod) > +{ > +} > +#endif /* !CONFIG_SYSFS */ > > /* This just allows us to keep track of which parameters are kmalloced. */ > struct kmalloced_param { > @@ -459,7 +469,7 @@ static int param_array(struct module *mod, > /* nul-terminate and parse */ > save = val[len]; > ((char *)val)[len] = '\0'; > - BUG_ON(!KPARAM_IS_LOCKED(mod)); > + check_kparam_locked(mod); > ret = set(val, &kp); > > if (ret != 0) > @@ -496,7 +506,7 @@ static int param_array_get(char *buffer, const struct kernel_param *kp) > if (i) > buffer[off++] = ','; > p.arg = arr->elem + arr->elemsize * i; > - BUG_ON(!KPARAM_IS_LOCKED(p.mod)); > + check_kparam_locked(p.mod); > ret = arr->ops->get(buffer + off, &p); > if (ret < 0) > return ret; > @@ -616,6 +626,7 @@ static ssize_t param_attr_store(struct module_attribute *mattr, > #define __modinit __init > #endif > > +#ifdef CONFIG_SYSFS > void kernel_param_lock(struct module *mod) > { > mutex_lock(KPARAM_MUTEX(mod)); > @@ -626,7 +637,6 @@ void kernel_param_unlock(struct module *mod) > mutex_unlock(KPARAM_MUTEX(mod)); > } > > -#ifdef CONFIG_SYSFS > EXPORT_SYMBOL(kernel_param_lock); > EXPORT_SYMBOL(kernel_param_unlock); > -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
