Hi Linus,
This is the "I have a reference count already, and I know the
admin has done rmmod --wait and so *really* wants to remove the
module, but I don't care" interface 8)
There are several places where handling the try_module_get()
failure is not worth it: fs/filesystems.c is the first.
Thanks!
Rusty.
-- Anyone who quotes me in their sig is an idiot. -- Rusty Russell.Name: __try_module_get Author: Rusty Russell Status: Trivial
D: Introduces __try_module_get for places where we know we already hold D: a reference and ignoring the fact that the module is being "rmmod --wait"ed D: is simpler.
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .22116-2.5.66-bk1-module_dup.pre/fs/filesystems.c .22116-2.5.66-bk1-module_dup/fs/filesystems.c --- .22116-2.5.66-bk1-module_dup.pre/fs/filesystems.c 2003-03-18 12:21:38.000000000 +1100 +++ .22116-2.5.66-bk1-module_dup/fs/filesystems.c 2003-03-26 14:11:23.000000000 +1100 @@ -32,17 +32,7 @@ static rwlock_t file_systems_lock = RW_L /* WARNING: This can be used only if we _already_ own a reference */ void get_filesystem(struct file_system_type *fs) { - if (!try_module_get(fs->owner)) { -#ifdef CONFIG_MODULE_UNLOAD - unsigned int cpu = get_cpu(); - local_inc(&fs->owner->ref[cpu].count); - put_cpu(); -#else - /* Getting filesystem while it's starting up? We're - already supposed to have a reference. */ - BUG(); -#endif - } + __try_module_get(fs->owner); } void put_filesystem(struct file_system_type *fs) diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .22116-2.5.66-bk1-module_dup.pre/include/linux/module.h .22116-2.5.66-bk1-module_dup/include/linux/module.h --- .22116-2.5.66-bk1-module_dup.pre/include/linux/module.h 2003-03-25 12:17:31.000000000 +1100 +++ .22116-2.5.66-bk1-module_dup/include/linux/module.h 2003-03-26 14:11:23.000000000 +1100 @@ -272,6 +272,7 @@ int module_text_address(unsigned long ad #ifdef CONFIG_MODULE_UNLOAD +unsigned int module_refcount(struct module *mod); void __symbol_put(const char *symbol); #define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x) void symbol_put_addr(void *addr); @@ -282,6 +283,17 @@ void symbol_put_addr(void *addr); #define local_dec(x) atomic_dec(x) #endif +/* Sometimes we know we already have a refcount, and it's easier not + to handle the error case (which only happens with rmmod --wait). */ +static inline void __try_module_get(struct module *module) +{ + if (module) { + BUG_ON(module_refcount(module) == 0); + local_inc(&module->ref[get_cpu()].count); + put_cpu(); + } +} + static inline int try_module_get(struct module *module) { int ret = 1; @@ -317,6 +329,9 @@ static inline int try_module_get(struct static inline void module_put(struct module *module) { } +static inline void __try_module_get(struct module *module) +{ +} #define symbol_put(x) do { } while(0) #define symbol_put_addr(p) do { } while(0) @@ -371,6 +386,10 @@ static inline int module_text_address(un #define symbol_put(x) do { } while(0) #define symbol_put_addr(x) do { } while(0) +static inline void __try_module_get(struct module *module) +{ +} + static inline int try_module_get(struct module *module) { return 1; diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .22116-2.5.66-bk1-module_dup.pre/kernel/module.c .22116-2.5.66-bk1-module_dup/kernel/module.c --- .22116-2.5.66-bk1-module_dup.pre/kernel/module.c 2003-03-18 05:01:52.000000000 +1100 +++ .22116-2.5.66-bk1-module_dup/kernel/module.c 2003-03-26 14:11:23.000000000 +1100 @@ -374,7 +374,7 @@ static inline void restart_refcounts(voi } #endif -static unsigned int module_refcount(struct module *mod) +unsigned int module_refcount(struct module *mod) { unsigned int i, total = 0; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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