[PATCH 1/3] snsc: switch from force_sig to kill_proc

[Christoph Hellwig <hch@lst.de>]

currently the snsc driver uses force_sig to send init a SIGPWR
when the system overheats.  This patch switches it to kill_proc
instead which has the following advantages:

 (1) gets rid of one of the last remaining tasklist_lock users
     in modular code
 (2) simplifies the snsc code significantly

The downside is that an init implementation could in theory block
SIGPWR and it would not get delivered.  The sysvinit code used by
all major distributions doesn't do this and blocking this signal
in init would be a rather stupid thing to do.


Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/drivers/char/snsc_event.c
===================================================================
--- linux-2.6.orig/drivers/char/snsc_event.c	2006-07-08 13:13:28.000000000 +0200
+++ linux-2.6/drivers/char/snsc_event.c	2006-07-08 13:14:21.000000000 +0200
@@ -220,20 +220,7 @@
 			       " Sending SIGPWR to init...\n");
 
 		/* give a SIGPWR signal to init proc */
-
-		/* first find init's task */
-		read_lock(&tasklist_lock);
-		for_each_process(p) {
-			if (p->pid == 1)
-				break;
-		}
-		if (p) {
-			force_sig(SIGPWR, p);
-		} else {
-			printk(KERN_ERR "Failed to signal init!\n");
-			snsc_shutting_down = 0; /* so can try again (?) */
-		}
-		read_unlock(&tasklist_lock);
+		kill_proc(1, SIGPWR, 0);
 	} else {
 		/* print to system log */
 		printk("%s|$(0x%x)%s\n", severity, esp_code, desc);