Messages in this thread Patch in this message | | | Date | Thu, 19 May 2005 01:00:47 +0200 | From | Per Svennerbrandt <> | Subject | [PATCH][RFC] __request_module: fixed argument request_module with waitflag |
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The following extracts the code in request_module which is responsible for executing modprobe into a new helper function called __request_module. This new function takes the wait flag which gets passed down to call_usermodeheper as an argument, allowing async execution of modprobe.
During the writing of this I've had a bit of a mental struggle about whether or not maybe call_modprobe is a better name for this and thus I'm fine with either one if anyone else has a preference.
Signed-off-by: Per Svennerbrandt <per.svennerbrandt@lbi.se>
--- linux-2.6.12-rc2/kernel/kmod.c.orig 2005-04-16 19:08:22.000000000 +0200 +++ linux-2.6.12-rc2/kernel/kmod.c 2005-05-12 23:50:00.000000000 +0200 @@ -49,6 +49,49 @@ */ char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; +int __request_module(char *name, int wait) +{ + int ret; + unsigned int max_modprobes; + static atomic_t kmod_concurrent = ATOMIC_INIT(0); +#define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ + static int kmod_loop_msg; + + char *argv[] = { modprobe_path, "-q", "--", name, NULL }; + static char *envp[] = { "HOME=/", + "TERM=linux", + "PATH=/sbin:/usr/sbin:/bin:/usr/bin", + NULL }; + + /* If modprobe needs a service that is in a module, we get a recursive + * loop. Limit the number of running kmod threads to max_threads/2 or + * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method + * would be to run the parents of this process, counting how many times + * kmod was invoked. That would mean accessing the internals of the + * process tables to get the command line, proc_pid_cmdline is static + * and it is not worth changing the proc code just to handle this case. + * KAO. + * + * "trace the ppid" is simple, but will fail if someone's + * parent exits. I think this is as good as it gets. --RR + */ + max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); + atomic_inc(&kmod_concurrent); + if (atomic_read(&kmod_concurrent) > max_modprobes) { + /* We may be blaming an innocent here, but unlikely */ + if (kmod_loop_msg++ < 5) + printk(KERN_ERR + "request_module: runaway loop modprobe %s\n", + name); + atomic_dec(&kmod_concurrent); + return -ENOMEM; + } + ret = call_usermodehelper(modprobe_path, argv, envp, wait); + atomic_dec(&kmod_concurrent); + return ret; +} +EXPORT_SYMBOL(__request_module); + /** * request_module - try to load a kernel module * @fmt: printf style format string for the name of the module @@ -67,50 +110,15 @@ int request_module(const char *fmt, ...) { va_list args; char module_name[MODULE_NAME_LEN]; - unsigned int max_modprobes; int ret; - char *argv[] = { modprobe_path, "-q", "--", module_name, NULL }; - static char *envp[] = { "HOME=/", - "TERM=linux", - "PATH=/sbin:/usr/sbin:/bin:/usr/bin", - NULL }; - static atomic_t kmod_concurrent = ATOMIC_INIT(0); -#define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */ - static int kmod_loop_msg; va_start(args, fmt); ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args); va_end(args); if (ret >= MODULE_NAME_LEN) return -ENAMETOOLONG; - /* If modprobe needs a service that is in a module, we get a recursive - * loop. Limit the number of running kmod threads to max_threads/2 or - * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method - * would be to run the parents of this process, counting how many times - * kmod was invoked. That would mean accessing the internals of the - * process tables to get the command line, proc_pid_cmdline is static - * and it is not worth changing the proc code just to handle this case. - * KAO. - * - * "trace the ppid" is simple, but will fail if someone's - * parent exits. I think this is as good as it gets. --RR - */ - max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT); - atomic_inc(&kmod_concurrent); - if (atomic_read(&kmod_concurrent) > max_modprobes) { - /* We may be blaming an innocent here, but unlikely */ - if (kmod_loop_msg++ < 5) - printk(KERN_ERR - "request_module: runaway loop modprobe %s\n", - module_name); - atomic_dec(&kmod_concurrent); - return -ENOMEM; - } - - ret = call_usermodehelper(modprobe_path, argv, envp, 1); - atomic_dec(&kmod_concurrent); - return ret; + return __request_module(module_name, 1); } EXPORT_SYMBOL(request_module); #endif /* CONFIG_KMOD */ --- linux-2.6.12-rc2/include/linux/kmod.h.orig 2005-03-02 08:37:49.000000000 +0100 +++ linux-2.6.12-rc2/include/linux/kmod.h 2005-05-12 23:53:22.000000000 +0200 @@ -28,8 +28,10 @@ #ifdef CONFIG_KMOD /* modprobe exit status on success, -ve on error. Return value * usually useless though. */ +extern int __request_module(char *name, int wait); extern int request_module(const char * name, ...) __attribute__ ((format (printf, 1, 2))); #else +static inline int __request_module(char *name, int wait) { return -ENOSYS; } static inline int request_module(const char * name, ...) { return -ENOSYS; } #endif - 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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