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authorRusty Russell <rusty@rustcorp.com.au>2015-01-22 01:43:14 +0100
committerRusty Russell <rusty@rustcorp.com.au>2015-01-22 01:45:54 +0100
commitd5db139ab3764640e0882a1746e7b9fdee33fd87 (patch)
tree62f806a29a43c749c84354fbef3bdaa21dc3ce6f
parentmodule: fix race in kallsyms resolution during module load success. (diff)
downloadlinux-d5db139ab3764640e0882a1746e7b9fdee33fd87.tar.xz
linux-d5db139ab3764640e0882a1746e7b9fdee33fd87.zip
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>
-rw-r--r--include/linux/module.h2
-rw-r--r--kernel/debug/kdb/kdb_main.c2
-rw-r--r--kernel/module.c17
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 =