This patch does three things to remove the requirement for #ifdef
CONFIG_KMOD in code:
1) Makes request_module() take args like sprintf. eg.
request_module("proto-%u", protonum);
2) Adds request_module_start()/request_module_end() macros, eg.
struct protocol protoptr;
request_module_start("proto-%u", protonum) {
/* search for protocol, set protoptr. */
} request_module_end(protoptr != NULL);
This loops once if !CONFIG_KMOD or protoptr != NULL after first
iteration, otherwise calls request_module and loops a second time.
3) Adds a request_module_unless() macro, eg:
protoptr = request_module_unless(protoptrs[proto],
"proto-%u", protonum);
The evaluates the condition (protoptrs[proto]), if true, returns
it, otherwise calls request_module and returns the (re-evaluated)
condition.
This patch doesn't actually convert any code,
Rusty.
-- Anyone who quotes me in their sig is an idiot. -- Rusty Russell.Name: Enhanced kmod macros Author: Rusty Russell Status: Simple Class: New Infrastructure Section: Kmod
D: This patch makes request_module() take args like snprintf, and adds D: three new support macros: request_module_start(), request_module_end() D: and request_module_unless(). Now there should be no reason to have D: gratuitous code or #ifdef CONFIG_KMOD throughout the kernel.
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.4.14-params/include/linux/kmod.h working-2.4.14-kmod-used/include/linux/kmod.h --- working-2.4.14-params/include/linux/kmod.h Wed Nov 14 17:56:18 2001 +++ working-2.4.14-kmod-used/include/linux/kmod.h Mon Nov 19 13:14:23 2001 @@ -23,9 +23,39 @@ #include <linux/errno.h> #ifdef CONFIG_KMOD -extern int request_module(const char * name); -#else -static inline int request_module(const char * name) { return -ENOSYS; } +/* ISO C99 would allow a request_module_once() macro like + list_for_each, by declaring the var in the for(). Soon, soon... --RR */ + +/* Start a request module loop: module will be requested the *second* time */ +#define request_module_start(format, arg...) \ +do { \ + int __r; \ + for (__r = 0; __r < 2; __r++ ?: request_module(format , ## arg)) { + +/* Stop first time (ie. don't request) if this condition is true. */ +#define request_module_end(cond) if (cond) break; } } while(0) + +/* Request module if this is false, then re-evaluate */ +#define request_module_unless(cond, format, arg...) \ +({ if (!cond) request_module(format , ## arg); (cond); }) + +/* Request a module (returns 0 on success, -errno otherwise). Keep + name << a page please! */ +int request_module(const char *format, ...) +__attribute__ ((format (printf, 1, 2))); + +#else /* !CONFIG_KMOD */ + +#define request_module_start(format, arg...) do { +#define request_module_end(cond) while(0) + +/* Request a module (returns 0 on success, -errno otherwise) */ +static inline int request_module(const char *format, ...) +__attribute__ ((format (printf, 1, 2))); + +static inline int request_module(const char * name, ...) { return -ENOSYS; } + +#define request_module_unless(cond, format, arg...) (cond) #endif extern int exec_usermodehelper(char *program_path, char *argv[], char *envp[]); diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal working-2.4.14-params/kernel/kmod.c working-2.4.14-kmod-used/kernel/kmod.c --- working-2.4.14-params/kernel/kmod.c Thu Nov 15 22:20:10 2001 +++ working-2.4.14-kmod-used/kernel/kmod.c Mon Nov 19 13:13:29 2001 @@ -14,6 +14,9 @@ Unblock all signals when we exec a usermode process. Shuu Yamaguchi <shuu@wondernetworkresources.com> December 2000 + + Reworked to be varargs. + Rusty Russell <rusty@rustcorp.com.au> 2001 */ #define __KERNEL_SYSCALLS__ @@ -151,26 +154,13 @@ ret = exec_usermodehelper(modprobe_path, argv, envp); if (ret) { printk(KERN_ERR - "kmod: failed to exec %s -s -k %s, errno = %d\n", + "kmod: failed to exec %s %s, errno = %d\n", modprobe_path, (char*) module_name, errno); } return ret; } -/** - * request_module - try to load a kernel module - * @module_name: Name of module - * - * Load a module using the user mode module loader. The function returns - * zero on success or a negative errno code on failure. Note that a - * successful module load does not mean the module did not then unload - * and exit on an error of its own. Callers must check that the service - * they requested is now available not blindly invoke it. - * - * If module auto-loading support is disabled then this function - * becomes a no-operation. - */ -int request_module(const char * module_name) +static int __request_module(const char *module_name) { pid_t pid; int waitpid_result; @@ -237,6 +227,47 @@ } return 0; } + +/** + * request_module - try to load a kernel module + * @format: sprintf-style format of module + * + * Load a module using the user mode module loader. The function + * returns zero on success or a negative errno code on failure. Note + * that a successful module load does not mean the module did not then + * unload and exit on an error of its own. Callers must check that the + * service they requested is now available not blindly invoke it; see + * request_module_start and request_module_end macros. Names longer + * than 256 characters will always fail. + * + * If module auto-loading support is disabled then this function + * becomes a no-operation. */ +int request_module(const char *format, ...) +{ + va_list args; + int namelen, ret; + + /* Don't allow request_module() before the root fs is mounted! */ + if (!current->fs->root) + return -ENOENT; /* FIXME: BUG(), but this happens... */ + + va_start(args, format); + /* get length we need */ + namelen = vsnprintf(NULL, 0, format, args); + if (namelen > 256) + return -ENOENT; + + { + char module[namelen + 1]; + vsprintf(module, format, args); + + ret = __request_module(module); + } + va_end(args); + + return ret; +} + #endif /* CONFIG_KMOD */ - 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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