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-rw-r--r--kernel/kprobes.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 17ec4afb0994..6fcf8dd148d0 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -87,6 +87,12 @@ struct kprobe_insn_page {
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);
@@ -130,8 +136,8 @@ kprobe_opcode_t __kprobes *get_insn_slot(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);
}
@@ -163,8 +169,8 @@ kprobe_opcode_t __kprobes *get_insn_slot(void)
}
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;
@@ -173,7 +179,7 @@ kprobe_opcode_t __kprobes *get_insn_slot(void)
/* 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) {
/*
@@ -212,7 +218,7 @@ static int __kprobes collect_garbage_slots(void)
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;
}
@@ -232,7 +238,7 @@ void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
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);