module: make module_refcount() a signed integer.

James Bottomley points out that it will be -1 during unload.  It's
only used for diagnostics, so let's not hide that as it could be a
clue as to what's gone wrong.

Cc: Jason Wessel <jason.wessel@windriver.com>
Acked-and-documention-added-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Masami Hiramatsu <maasami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

3 files changed, 15 insertions, 6 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index ebfb0e153c6a..b653d7c0a05a 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -444,7 +444,7 @@ extern void __module_put_and_exit(struct module *mod, long code)
 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code)
 
 #ifdef CONFIG_MODULE_UNLOAD
-unsigned long module_refcount(struct module *mod);
+int module_refcount(struct module *mod);
 void __symbol_put(const char *symbol);
 #define symbol_put(x) __symbol_put(VMLINUX_SYMBOL_STR(x))
 void symbol_put_addr(void *addr);
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 379650b984f8..2934889f2cce 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1979,7 +1979,7 @@ static int kdb_lsmod(int argc, const char **argv)
                 kdb_printf("%-20s%8u  0x%p ", mod->name,
                            mod->core_size, (void *)mod);
 #ifdef CONFIG_MODULE_UNLOAD
-                kdb_printf("%4ld ", module_refcount(mod));
+                kdb_printf("%4d ", module_refcount(mod));
 #endif
                 if (mod->state == MODULE_STATE_GOING)
                         kdb_printf(" (Unloading)");
diff --git a/kernel/module.c b/kernel/module.c
index ed4ec9c30bd2..d856e96a3cce 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -772,9 +772,18 @@ static int try_stop_module(struct module *mod, int flags, int *forced)
         return 0;
 }
 
-unsigned long module_refcount(struct module *mod)
+/**
+ * module_refcount - return the refcount or -1 if unloading
+ *
+ * @mod:        the module we're checking
+ *
+ * Returns:
+ *      -1 if the module is in the process of unloading
+ *      otherwise the number of references in the kernel to the module
+ */
+int module_refcount(struct module *mod)
 {
-        return (unsigned long)atomic_read(&mod->refcnt) - MODULE_REF_BASE;
+        return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
 }
 EXPORT_SYMBOL(module_refcount);
 
@@ -856,7 +865,7 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
         struct module_use *use;
         int printed_something = 0;
 
-        seq_printf(m, " %lu ", module_refcount(mod));
+        seq_printf(m, " %i ", module_refcount(mod));
 
         /*
          * Always include a trailing , so userspace can differentiate
@@ -908,7 +917,7 @@ EXPORT_SYMBOL_GPL(symbol_put_addr);
 static ssize_t show_refcnt(struct module_attribute *mattr,
                            struct module_kobject *mk, char *buffer)
 {
-        return sprintf(buffer, "%lu\n", module_refcount(mk->mod));
+        return sprintf(buffer, "%i\n", module_refcount(mk->mod));
 }
 
 static struct module_attribute modinfo_refcnt =