[PATCH] kprobes: replace magic numbers with enum

Replace the magic numbers with an enum, and gets rid of a warning on the
specific architectures (ex. powerpc) on which the compiler considers
'char' as 'unsigned char'.

Signed-off-by: Masami Hiramatsu <[e-mail]>
Cc: Prasanna S Panchamukhi <[e-mail]>
Cc: Ananth N Mavinakayanahalli <[e-mail]>
Cc: Anil S Keshavamurthy <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

kernel/kprobes.c

···
 	int ngarbage;
 };
 
+enum kprobe_slot_state {
+	SLOT_CLEAN = 0,
+	SLOT_DIRTY = 1,
+	SLOT_USED = 2,
+};
+
 static struct hlist_head kprobe_insn_pages;
 static int kprobe_garbage_slots;
 static int collect_garbage_slots(void);
···
 		if (kip->nused < INSNS_PER_PAGE) {
 			int i;
 			for (i = 0; i < INSNS_PER_PAGE; i++) {
-				if (!kip->slot_used[i]) {
-					kip->slot_used[i] = 1;
+				if (kip->slot_used[i] == SLOT_CLEAN) {
+					kip->slot_used[i] = SLOT_USED;
 					kip->nused++;
 					return kip->insns + (i * MAX_INSN_SIZE);
 				}
···
 	}
 	INIT_HLIST_NODE(&kip->hlist);
 	hlist_add_head(&kip->hlist, &kprobe_insn_pages);
-	memset(kip->slot_used, 0, INSNS_PER_PAGE);
-	kip->slot_used[0] = 1;
+	memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
+	kip->slot_used[0] = SLOT_USED;
 	kip->nused = 1;
 	kip->ngarbage = 0;
 	return kip->insns;
···
 /* Return 1 if all garbages are collected, otherwise 0. */
 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
 {
-	kip->slot_used[idx] = 0;
+	kip->slot_used[idx] = SLOT_CLEAN;
 	kip->nused--;
 	if (kip->nused == 0) {
 		/*
···
 			continue;
 		kip->ngarbage = 0;	/* we will collect all garbages */
 		for (i = 0; i < INSNS_PER_PAGE; i++) {
-			if (kip->slot_used[i] == -1 &&
+			if (kip->slot_used[i] == SLOT_DIRTY &&
 			    collect_one_slot(kip, i))
 				break;
 		}
···
 		    slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
 			int i = (slot - kip->insns) / MAX_INSN_SIZE;
 			if (dirty) {
-				kip->slot_used[i] = -1;
+				kip->slot_used[i] = SLOT_DIRTY;
 				kip->ngarbage++;
 			} else {
 				collect_one_slot(kip, i);