Dan Streetman <ddstr...@ieee.org> 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?
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 <s...@canb.auug.org.au>
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);
/* 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);
--
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