From: Rusty Russell <rusty@rustcorp.com.au>
MODULE_ALIAS_BLOCK() and MODULE_ALIAS_CHAR() define aliases of form
"XXX-<major>-<minor>", so we should probe for modules using this form.
Unfortunately in 2.4, block aliases were "XXX-<major>" and char aliases
were of both forms.
Ideally, all modules would now be using MODULE_ALIAS() macros to define
their aliases, and the old configuration files wouldn't matter as much.
Unfortunately, this hasn't happened, so we make request_module() return the
exit status of modprobe, and then do fallback when probing for char and
block devices.
(Kudos to Chris Wright, I stole his kernel_thread flags).
drivers/block/genhd.c | 4 +++-
fs/char_dev.c | 4 +++-
include/linux/kmod.h | 2 ++
kernel/kmod.c | 17 +++++++++++------
4 files changed, 19 insertions(+), 8 deletions(-)
diff -puN drivers/block/genhd.c~call_usermodehelper-retval-fix-4 drivers/block/genhd.c
--- 25/drivers/block/genhd.c~call_usermodehelper-retval-fix-4 2003-12-21 22:41:10.000000000 -0800
+++ 25-akpm/drivers/block/genhd.c 2003-12-21 22:41:10.000000000 -0800
@@ -296,7 +296,9 @@ extern int blk_dev_init(void);
static struct kobject *base_probe(dev_t dev, int *part, void *data)
{
- request_module("block-major-%d", MAJOR(dev));
+ if (request_module("block-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
+ /* Make old-style 2.4 aliases work */
+ request_module("block-major-%d", MAJOR(dev));
return NULL;
}
diff -puN fs/char_dev.c~call_usermodehelper-retval-fix-4 fs/char_dev.c
--- 25/fs/char_dev.c~call_usermodehelper-retval-fix-4 2003-12-21 22:41:10.000000000 -0800
+++ 25-akpm/fs/char_dev.c 2003-12-21 22:41:10.000000000 -0800
@@ -434,7 +434,9 @@ void cdev_init(struct cdev *cdev, struct
static struct kobject *base_probe(dev_t dev, int *part, void *data)
{
- request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev));
+ if (request_module("char-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
+ /* Make old-style 2.4 aliases work */
+ request_module("char-major-%d", MAJOR(dev));
return NULL;
}
diff -puN include/linux/kmod.h~call_usermodehelper-retval-fix-4 include/linux/kmod.h
--- 25/include/linux/kmod.h~call_usermodehelper-retval-fix-4 2003-12-21 22:41:10.000000000 -0800
+++ 25-akpm/include/linux/kmod.h 2003-12-21 22:41:10.000000000 -0800
@@ -24,6 +24,8 @@
#include <linux/compiler.h>
#ifdef CONFIG_KMOD
+/* modprobe exit status on success, -ve on error. Return value
+ * usually useless though. */
extern int request_module(const char * name, ...) __attribute__ ((format (printf, 1, 2)));
#else
static inline int request_module(const char * name, ...) { return -ENOSYS; }
diff -puN kernel/kmod.c~call_usermodehelper-retval-fix-4 kernel/kmod.c
--- 25/kernel/kmod.c~call_usermodehelper-retval-fix-4 2003-12-21 22:41:10.000000000 -0800
+++ 25-akpm/kernel/kmod.c 2003-12-21 22:41:10.000000000 -0800
@@ -182,16 +182,21 @@ static int wait_for_helper(void *data)
{
struct subprocess_info *sub_info = data;
pid_t pid;
+ struct k_sigaction sa;
+
+ /* Install a handler: if SIGCLD isn't handled sys_wait4 won't
+ * populate the status, but will return -ECHILD. */
+ sa.sa.sa_handler = SIG_IGN;
+ sa.sa.sa_flags = 0;
+ siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD));
+ do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0);
+ allow_signal(SIGCHLD);
- sub_info->retval = 0;
pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD);
if (pid < 0)
sub_info->retval = pid;
else
- /* We don't have a SIGCHLD signal handler, so this
- * always returns -ECHILD, but the important thing is
- * that it blocks. */
- sys_wait4(pid, NULL, 0, NULL);
+ sys_wait4(pid, &sub_info->retval, 0, NULL);
complete(sub_info->complete);
return 0;
@@ -210,7 +215,7 @@ static void __call_usermodehelper(void *
* until that is done. */
if (sub_info->wait)
pid = kernel_thread(wait_for_helper, sub_info,
- CLONE_KERNEL | SIGCHLD);
+ CLONE_FS | CLONE_FILES | SIGCHLD);
else
pid = kernel_thread(____call_usermodehelper, sub_info,
CLONE_VFORK | SIGCHLD);
_