diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index e61a7403f3d..5fff40c9ff5 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -112,7 +112,7 @@ struct ftrace_event_call {
 #endif
 };
 
-#define MAX_FILTER_PRED		8
+#define MAX_FILTER_PRED		32
 #define MAX_FILTER_STR_VAL	128
 
 extern int init_preds(struct ftrace_event_call *call);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 866d0108fd2..7736fe8c1b7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -735,6 +735,7 @@ struct ftrace_event_field {
 struct event_filter {
 	int			n_preds;
 	struct filter_pred	**preds;
+	char			*filter_string;
 };
 
 struct event_subsystem {
@@ -746,7 +747,8 @@ struct event_subsystem {
 
 struct filter_pred;
 
-typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event);
+typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
+				 int val1, int val2);
 
 struct filter_pred {
 	filter_pred_fn_t fn;
@@ -756,23 +758,18 @@ struct filter_pred {
 	char *field_name;
 	int offset;
 	int not;
-	int or;
-	int compound;
-	int clear;
+	int op;
+	int pop_n;
 };
 
-extern void filter_free_pred(struct filter_pred *pred);
-extern void filter_print_preds(struct ftrace_event_call *call,
+extern void print_event_filter(struct ftrace_event_call *call,
 			       struct trace_seq *s);
-extern int filter_parse(char **pbuf, struct filter_pred *pred);
-extern int filter_add_pred(struct ftrace_event_call *call,
-			   struct filter_pred *pred);
-extern void filter_disable_preds(struct ftrace_event_call *call);
-extern void filter_free_subsystem_preds(struct event_subsystem *system);
-extern void filter_print_subsystem_preds(struct event_subsystem *system,
+extern int apply_event_filter(struct ftrace_event_call *call,
+			      char *filter_string);
+extern int apply_subsystem_event_filter(struct event_subsystem *system,
+					char *filter_string);
+extern void print_subsystem_event_filter(struct event_subsystem *system,
 					 struct trace_seq *s);
-extern int filter_add_subsystem_pred(struct event_subsystem *system,
-				     struct filter_pred *pred);
 
 static inline int
 filter_check_discard(struct ftrace_event_call *call, void *rec,
@@ -787,6 +784,47 @@ filter_check_discard(struct ftrace_event_call *call, void *rec,
 	return 0;
 }
 
+#define DEFINE_COMPARISON_PRED(type)					\
+static int filter_pred_##type(struct filter_pred *pred, void *event,	\
+			      int val1, int val2)			\
+{									\
+	type *addr = (type *)(event + pred->offset);			\
+	type val = (type)pred->val;					\
+	int match = 0;							\
+									\
+	switch (pred->op) {						\
+	case OP_LT:							\
+		match = (*addr < val);					\
+		break;							\
+	case OP_LE:							\
+		match = (*addr <= val);					\
+		break;							\
+	case OP_GT:							\
+		match = (*addr > val);					\
+		break;							\
+	case OP_GE:							\
+		match = (*addr >= val);					\
+		break;							\
+	default:							\
+		break;							\
+	}								\
+									\
+	return match;							\
+}
+
+#define DEFINE_EQUALITY_PRED(size)					\
+static int filter_pred_##size(struct filter_pred *pred, void *event,	\
+			      int val1, int val2)			\
+{									\
+	u##size *addr = (u##size *)(event + pred->offset);		\
+	u##size val = (u##size)pred->val;				\
+	int match;							\
+									\
+	match = (val == *addr) ^ pred->not;				\
+									\
+	return match;							\
+}
+
 extern struct list_head ftrace_events;
 
 extern const char *__start___trace_bprintk_fmt[];
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index bbbea747937..f789ca540fe 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -492,7 +492,7 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 
 	trace_seq_init(s);
 
-	filter_print_preds(call, s);
+	print_event_filter(call, s);
 	r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 
 	kfree(s);
@@ -505,40 +505,26 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		   loff_t *ppos)
 {
 	struct ftrace_event_call *call = filp->private_data;
-	char buf[64], *pbuf = buf;
-	struct filter_pred *pred;
+	char *buf;
 	int err;
 
-	if (cnt >= sizeof(buf))
+	if (cnt >= PAGE_SIZE)
 		return -EINVAL;
 
-	if (copy_from_user(&buf, ubuf, cnt))
-		return -EFAULT;
-	buf[cnt] = '\0';
-
-	pred = kzalloc(sizeof(*pred), GFP_KERNEL);
-	if (!pred)
+	buf = (char *)__get_free_page(GFP_TEMPORARY);
+	if (!buf)
 		return -ENOMEM;
 
-	err = filter_parse(&pbuf, pred);
-	if (err < 0) {
-		filter_free_pred(pred);
+	if (copy_from_user(buf, ubuf, cnt)) {
+		free_page((unsigned long) buf);
+		return -EFAULT;
+	}
+	buf[cnt] = '\0';
+
+	err = apply_event_filter(call, buf);
+	free_page((unsigned long) buf);
+	if (err < 0)
 		return err;
-	}
-
-	if (pred->clear) {
-		filter_disable_preds(call);
-		filter_free_pred(pred);
-		return cnt;
-	}
-
-	err = filter_add_pred(call, pred);
-	if (err < 0) {
-		filter_free_pred(pred);
-		return err;
-	}
-
-	filter_free_pred(pred);
 
 	*ppos += cnt;
 
@@ -562,7 +548,7 @@ subsystem_filter_read(struct file *filp, char __user *ubuf, size_t cnt,
 
 	trace_seq_init(s);
 
-	filter_print_subsystem_preds(system, s);
+	print_subsystem_event_filter(system, s);
 	r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
 
 	kfree(s);
@@ -575,38 +561,26 @@ subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
 		       loff_t *ppos)
 {
 	struct event_subsystem *system = filp->private_data;
-	char buf[64], *pbuf = buf;
-	struct filter_pred *pred;
+	char *buf;
 	int err;
 
-	if (cnt >= sizeof(buf))
+	if (cnt >= PAGE_SIZE)
 		return -EINVAL;
 
-	if (copy_from_user(&buf, ubuf, cnt))
-		return -EFAULT;
-	buf[cnt] = '\0';
-
-	pred = kzalloc(sizeof(*pred), GFP_KERNEL);
-	if (!pred)
+	buf = (char *)__get_free_page(GFP_TEMPORARY);
+	if (!buf)
 		return -ENOMEM;
 
-	err = filter_parse(&pbuf, pred);
-	if (err < 0) {
-		filter_free_pred(pred);
-		return err;
+	if (copy_from_user(buf, ubuf, cnt)) {
+		free_page((unsigned long) buf);
+		return -EFAULT;
 	}
+	buf[cnt] = '\0';
 
-	if (pred->clear) {
-		filter_free_subsystem_preds(system);
-		filter_free_pred(pred);
-		return cnt;
-	}
-
-	err = filter_add_subsystem_pred(system, pred);
-	if (err < 0) {
-		filter_free_pred(pred);
+	err = apply_subsystem_event_filter(system, buf);
+	free_page((unsigned long) buf);
+	if (err < 0)
 		return err;
-	}
 
 	*ppos += cnt;
 
@@ -760,11 +734,21 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
 
 	system->filter = NULL;
 
+	system->filter = kzalloc(sizeof(struct event_filter), GFP_KERNEL);
+	if (!system->filter) {
+		pr_warning("Could not allocate filter for subsystem "
+			   "'%s'\n", name);
+		return system->entry;
+	}
+
 	entry = debugfs_create_file("filter", 0644, system->entry, system,
 				    &ftrace_subsystem_filter_fops);
-	if (!entry)
+	if (!entry) {
+		kfree(system->filter);
+		system->filter = NULL;
 		pr_warning("Could not create debugfs "
 			   "'%s/filter' entry\n", name);
+	}
 
 	return system->entry;
 }
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 1e861eca3d0..f49486687ee 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -29,51 +29,130 @@
 
 static DEFINE_MUTEX(filter_mutex);
 
-static int filter_pred_64(struct filter_pred *pred, void *event)
+enum filter_op_ids
 {
-	u64 *addr = (u64 *)(event + pred->offset);
-	u64 val = (u64)pred->val;
-	int match;
+	OP_OR,
+	OP_AND,
+	OP_NE,
+	OP_EQ,
+	OP_LT,
+	OP_LE,
+	OP_GT,
+	OP_GE,
+	OP_NONE,
+	OP_OPEN_PAREN,
+};
 
-	match = (val == *addr) ^ pred->not;
+struct filter_op {
+	int id;
+	char *string;
+	int precedence;
+};
 
-	return match;
+static struct filter_op filter_ops[] = {
+	{ OP_OR, "||", 1 },
+	{ OP_AND, "&&", 2 },
+	{ OP_NE, "!=", 4 },
+	{ OP_EQ, "==", 4 },
+	{ OP_LT, "<", 5 },
+	{ OP_LE, "<=", 5 },
+	{ OP_GT, ">", 5 },
+	{ OP_GE, ">=", 5 },
+	{ OP_NONE, "OP_NONE", 0 },
+	{ OP_OPEN_PAREN, "(", 0 },
+};
+
+enum {
+	FILT_ERR_NONE,
+	FILT_ERR_INVALID_OP,
+	FILT_ERR_UNBALANCED_PAREN,
+	FILT_ERR_TOO_MANY_OPERANDS,
+	FILT_ERR_OPERAND_TOO_LONG,
+	FILT_ERR_FIELD_NOT_FOUND,
+	FILT_ERR_ILLEGAL_FIELD_OP,
+	FILT_ERR_ILLEGAL_INTVAL,
+	FILT_ERR_BAD_SUBSYS_FILTER,
+	FILT_ERR_TOO_MANY_PREDS,
+	FILT_ERR_MISSING_FIELD,
+	FILT_ERR_INVALID_FILTER,
+};
+
+static char *err_text[] = {
+	"No error",
+	"Invalid operator",
+	"Unbalanced parens",
+	"Too many operands",
+	"Operand too long",
+	"Field not found",
+	"Illegal operation for field type",
+	"Illegal integer value",
+	"Couldn't find or set field in one of a subsystem's events",
+	"Too many terms in predicate expression",
+	"Missing field name and/or value",
+	"Meaningless filter expression",
+};
+
+struct opstack_op {
+	int op;
+	struct list_head list;
+};
+
+struct postfix_elt {
+	int op;
+	char *operand;
+	struct list_head list;
+};
+
+struct filter_parse_state {
+	struct filter_op *ops;
+	struct list_head opstack;
+	struct list_head postfix;
+	int lasterr;
+	int lasterr_pos;
+
+	struct {
+		char *string;
+		unsigned int cnt;
+		unsigned int tail;
+	} infix;
+
+	struct {
+		char string[MAX_FILTER_STR_VAL];
+		int pos;
+		unsigned int tail;
+	} operand;
+};
+
+DEFINE_COMPARISON_PRED(s64);
+DEFINE_COMPARISON_PRED(u64);
+DEFINE_COMPARISON_PRED(s32);
+DEFINE_COMPARISON_PRED(u32);
+DEFINE_COMPARISON_PRED(s16);
+DEFINE_COMPARISON_PRED(u16);
+DEFINE_COMPARISON_PRED(s8);
+DEFINE_COMPARISON_PRED(u8);
+
+DEFINE_EQUALITY_PRED(64);
+DEFINE_EQUALITY_PRED(32);
+DEFINE_EQUALITY_PRED(16);
+DEFINE_EQUALITY_PRED(8);
+
+static int filter_pred_and(struct filter_pred *pred __attribute((unused)),
+			   void *event __attribute((unused)),
+			   int val1, int val2)
+{
+	return val1 && val2;
 }
 
-static int filter_pred_32(struct filter_pred *pred, void *event)
+static int filter_pred_or(struct filter_pred *pred __attribute((unused)),
+			  void *event __attribute((unused)),
+			  int val1, int val2)
 {
-	u32 *addr = (u32 *)(event + pred->offset);
-	u32 val = (u32)pred->val;
-	int match;
-
-	match = (val == *addr) ^ pred->not;
-
-	return match;
+	return val1 || val2;
 }
 
-static int filter_pred_16(struct filter_pred *pred, void *event)
-{
-	u16 *addr = (u16 *)(event + pred->offset);
-	u16 val = (u16)pred->val;
-	int match;
-
-	match = (val == *addr) ^ pred->not;
-
-	return match;
-}
-
-static int filter_pred_8(struct filter_pred *pred, void *event)
-{
-	u8 *addr = (u8 *)(event + pred->offset);
-	u8 val = (u8)pred->val;
-	int match;
-
-	match = (val == *addr) ^ pred->not;
-
-	return match;
-}
-
-static int filter_pred_string(struct filter_pred *pred, void *event)
+static int filter_pred_string(struct filter_pred *pred, void *event,
+			      int val1, int val2)
 {
 	char *addr = (char *)(event + pred->offset);
 	int cmp, match;
@@ -85,7 +164,8 @@ static int filter_pred_string(struct filter_pred *pred, void *event)
 	return match;
 }
 
-static int filter_pred_none(struct filter_pred *pred, void *event)
+static int filter_pred_none(struct filter_pred *pred, void *event,
+			    int val1, int val2)
 {
 	return 0;
 }
@@ -94,66 +174,119 @@ static int filter_pred_none(struct filter_pred *pred, void *event)
 int filter_match_preds(struct ftrace_event_call *call, void *rec)
 {
 	struct event_filter *filter = call->filter;
-	int i, matched, and_failed = 0;
+	int match, top = 0, val1 = 0, val2 = 0;
+	int stack[MAX_FILTER_PRED];
 	struct filter_pred *pred;
+	int i;
 
 	for (i = 0; i < filter->n_preds; i++) {
 		pred = filter->preds[i];
-		if (and_failed && !pred->or)
+		if (!pred->pop_n) {
+			match = pred->fn(pred, rec, val1, val2);
+			stack[top++] = match;
 			continue;
-		matched = pred->fn(pred, rec);
-		if (!matched && !pred->or) {
-			and_failed = 1;
-			continue;
-		} else if (matched && pred->or)
-			return 1;
+		}
+		if (pred->pop_n > top) {
+			WARN_ON_ONCE(1);
+			return 0;
+		}
+		val1 = stack[--top];
+		val2 = stack[--top];
+		match = pred->fn(pred, rec, val1, val2);
+		stack[top++] = match;
 	}
 
-	if (and_failed)
-		return 0;
-
-	return 1;
+	return stack[--top];
 }
 EXPORT_SYMBOL_GPL(filter_match_preds);
 
-static void __filter_print_preds(struct event_filter *filter,
-				 struct trace_seq *s)
+static void parse_error(struct filter_parse_state *ps, int err, int pos)
 {
-	struct filter_pred *pred;
-	char *field_name;
-	int i;
-
-	if (!filter || !filter->n_preds) {
-		trace_seq_printf(s, "none\n");
-		return;
-	}
-
-	for (i = 0; i < filter->n_preds; i++) {
-		pred = filter->preds[i];
-		field_name = pred->field_name;
-		if (i)
-			trace_seq_printf(s, pred->or ? "|| " : "&& ");
-		trace_seq_printf(s, "%s ", field_name);
-		trace_seq_printf(s, pred->not ? "!= " : "== ");
-		if (pred->str_len)
-			trace_seq_printf(s, "%s\n", pred->str_val);
-		else
-			trace_seq_printf(s, "%llu\n", pred->val);
-	}
+	ps->lasterr = err;
+	ps->lasterr_pos = pos;
 }
 
-void filter_print_preds(struct ftrace_event_call *call, struct trace_seq *s)
+static void remove_filter_string(struct event_filter *filter)
 {
+	kfree(filter->filter_string);
+	filter->filter_string = NULL;
+}
+
+static int replace_filter_string(struct event_filter *filter,
+				 char *filter_string)
+{
+	kfree(filter->filter_string);
+	filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
+	if (!filter->filter_string)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int append_filter_string(struct event_filter *filter,
+				char *string)
+{
+	int newlen;
+	char *new_filter_string;
+
+	BUG_ON(!filter->filter_string);
+	newlen = strlen(filter->filter_string) + strlen(string) + 1;
+	new_filter_string = kmalloc(newlen, GFP_KERNEL);
+	if (!new_filter_string)
+		return -ENOMEM;
+
+	strcpy(new_filter_string, filter->filter_string);
+	strcat(new_filter_string, string);
+	kfree(filter->filter_string);
+	filter->filter_string = new_filter_string;
+
+	return 0;
+}
+
+static void append_filter_err(struct filter_parse_state *ps,
+			      struct event_filter *filter)
+{
+	int pos = ps->lasterr_pos;
+	char *buf, *pbuf;
+
+	buf = (char *)__get_free_page(GFP_TEMPORARY);
+	if (!buf)
+		return;
+
+	append_filter_string(filter, "\n");
+	memset(buf, ' ', PAGE_SIZE);
+	if (pos > PAGE_SIZE - 128)
+		pos = 0;
+	buf[pos] = '^';
+	pbuf = &buf[pos] + 1;
+
+	sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
+	append_filter_string(filter, buf);
+	free_page((unsigned long) buf);
+}
+
+void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
+{
+	struct event_filter *filter = call->filter;
+
 	mutex_lock(&filter_mutex);
-	__filter_print_preds(call->filter, s);
+	if (filter->filter_string)
+		trace_seq_printf(s, "%s\n", filter->filter_string);
+	else
+		trace_seq_printf(s, "none\n");
 	mutex_unlock(&filter_mutex);
 }
 
-void filter_print_subsystem_preds(struct event_subsystem *system,
+void print_subsystem_event_filter(struct event_subsystem *system,
 				  struct trace_seq *s)
 {
+	struct event_filter *filter = system->filter;
+
 	mutex_lock(&filter_mutex);
-	__filter_print_preds(system->filter, s);
+	if (filter->filter_string)
+		trace_seq_printf(s, "%s\n", filter->filter_string);
+	else
+		trace_seq_printf(s, "none\n");
 	mutex_unlock(&filter_mutex);
 }
 
@@ -170,7 +303,7 @@ find_event_field(struct ftrace_event_call *call, char *name)
 	return NULL;
 }
 
-void filter_free_pred(struct filter_pred *pred)
+static void filter_free_pred(struct filter_pred *pred)
 {
 	if (!pred)
 		return;
@@ -191,15 +324,17 @@ static int filter_set_pred(struct filter_pred *dest,
 			   filter_pred_fn_t fn)
 {
 	*dest = *src;
-	dest->field_name = kstrdup(src->field_name, GFP_KERNEL);
-	if (!dest->field_name)
-		return -ENOMEM;
+	if (src->field_name) {
+		dest->field_name = kstrdup(src->field_name, GFP_KERNEL);
+		if (!dest->field_name)
+			return -ENOMEM;
+	}
 	dest->fn = fn;
 
 	return 0;
 }
 
-static void __filter_disable_preds(struct ftrace_event_call *call)
+static void filter_disable_preds(struct ftrace_event_call *call)
 {
 	struct event_filter *filter = call->filter;
 	int i;
@@ -211,13 +346,6 @@ static void __filter_disable_preds(struct ftrace_event_call *call)
 		filter->preds[i]->fn = filter_pred_none;
 }
 
-void filter_disable_preds(struct ftrace_event_call *call)
-{
-	mutex_lock(&filter_mutex);
-	__filter_disable_preds(call);
-	mutex_unlock(&filter_mutex);
-}
-
 int init_preds(struct ftrace_event_call *call)
 {
 	struct event_filter *filter;
@@ -258,48 +386,43 @@ oom:
 }
 EXPORT_SYMBOL_GPL(init_preds);
 
-static void __filter_free_subsystem_preds(struct event_subsystem *system)
+static void filter_free_subsystem_preds(struct event_subsystem *system)
 {
 	struct event_filter *filter = system->filter;
 	struct ftrace_event_call *call;
 	int i;
 
-	if (filter && filter->n_preds) {
+	if (filter->n_preds) {
 		for (i = 0; i < filter->n_preds; i++)
 			filter_free_pred(filter->preds[i]);
 		kfree(filter->preds);
-		kfree(filter);
-		system->filter = NULL;
+		filter->preds = NULL;
+		filter->n_preds = 0;
 	}
 
 	list_for_each_entry(call, &ftrace_events, list) {
 		if (!call->define_fields)
 			continue;
 
-		if (!strcmp(call->system, system->name))
-			__filter_disable_preds(call);
+		if (!strcmp(call->system, system->name)) {
+			filter_disable_preds(call);
+			remove_filter_string(call->filter);
+		}
 	}
 }
 
-void filter_free_subsystem_preds(struct event_subsystem *system)
-{
-	mutex_lock(&filter_mutex);
-	__filter_free_subsystem_preds(system);
-	mutex_unlock(&filter_mutex);
-}
-
-static int filter_add_pred_fn(struct ftrace_event_call *call,
+static int filter_add_pred_fn(struct filter_parse_state *ps,
+			      struct ftrace_event_call *call,
 			      struct filter_pred *pred,
 			      filter_pred_fn_t fn)
 {
 	struct event_filter *filter = call->filter;
 	int idx, err;
 
-	if (filter->n_preds && !pred->compound)
-		__filter_disable_preds(call);
-
-	if (filter->n_preds == MAX_FILTER_PRED)
+	if (filter->n_preds == MAX_FILTER_PRED) {
+		parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
 		return -ENOSPC;
+	}
 
 	idx = filter->n_preds;
 	filter_clear_pred(filter->preds[idx]);
@@ -321,94 +444,132 @@ static int is_string_field(const char *type)
 	return 0;
 }
 
-static int __filter_add_pred(struct ftrace_event_call *call,
-			     struct filter_pred *pred)
+static int is_legal_op(struct ftrace_event_field *field, int op)
+{
+	if (is_string_field(field->type) && (op != OP_EQ && op != OP_NE))
+		return 0;
+
+	return 1;
+}
+
+static filter_pred_fn_t select_comparison_fn(int op, int field_size,
+					     int field_is_signed)
+{
+	filter_pred_fn_t fn = NULL;
+
+	switch (field_size) {
+	case 8:
+		if (op == OP_EQ || op == OP_NE)
+			fn = filter_pred_64;
+		else if (field_is_signed)
+			fn = filter_pred_s64;
+		else
+			fn = filter_pred_u64;
+		break;
+	case 4:
+		if (op == OP_EQ || op == OP_NE)
+			fn = filter_pred_32;
+		else if (field_is_signed)
+			fn = filter_pred_s32;
+		else
+			fn = filter_pred_u32;
+		break;
+	case 2:
+		if (op == OP_EQ || op == OP_NE)
+			fn = filter_pred_16;
+		else if (field_is_signed)
+			fn = filter_pred_s16;
+		else
+			fn = filter_pred_u16;
+		break;
+	case 1:
+		if (op == OP_EQ || op == OP_NE)
+			fn = filter_pred_8;
+		else if (field_is_signed)
+			fn = filter_pred_s8;
+		else
+			fn = filter_pred_u8;
+		break;
+	}
+
+	return fn;
+}
+
+static int filter_add_pred(struct filter_parse_state *ps,
+			   struct ftrace_event_call *call,
+			   struct filter_pred *pred)
 {
 	struct ftrace_event_field *field;
 	filter_pred_fn_t fn;
 	unsigned long long val;
 
-	field = find_event_field(call, pred->field_name);
-	if (!field)
-		return -EINVAL;
-
 	pred->fn = filter_pred_none;
+
+	if (pred->op == OP_AND) {
+		pred->pop_n = 2;
+		return filter_add_pred_fn(ps, call, pred, filter_pred_and);
+	} else if (pred->op == OP_OR) {
+		pred->pop_n = 2;
+		return filter_add_pred_fn(ps, call, pred, filter_pred_or);
+	}
+
+	field = find_event_field(call, pred->field_name);
+	if (!field) {
+		parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
+		return -EINVAL;
+	}
+
 	pred->offset = field->offset;
 
+	if (!is_legal_op(field, pred->op)) {
+		parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
+		return -EINVAL;
+	}
+
 	if (is_string_field(field->type)) {
 		fn = filter_pred_string;
 		pred->str_len = field->size;
-		return filter_add_pred_fn(call, pred, fn);
+		if (pred->op == OP_NE)
+			pred->not = 1;
+		return filter_add_pred_fn(ps, call, pred, fn);
 	} else {
-		if (strict_strtoull(pred->str_val, 0, &val))
+		if (strict_strtoull(pred->str_val, 0, &val)) {
+			parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
 			return -EINVAL;
+		}
 		pred->val = val;
 	}
 
-	switch (field->size) {
-	case 8:
-		fn = filter_pred_64;
-		break;
-	case 4:
-		fn = filter_pred_32;
-		break;
-	case 2:
-		fn = filter_pred_16;
-		break;
-	case 1:
-		fn = filter_pred_8;
-		break;
-	default:
+	fn = select_comparison_fn(pred->op, field->size, field->is_signed);
+	if (!fn) {
+		parse_error(ps, FILT_ERR_INVALID_OP, 0);
 		return -EINVAL;
 	}
 
-	return filter_add_pred_fn(call, pred, fn);
+	if (pred->op == OP_NE)
+		pred->not = 1;
+
+	return filter_add_pred_fn(ps, call, pred, fn);
 }
 
-int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
-{
-	int err;
-
-	mutex_lock(&filter_mutex);
-	err = __filter_add_pred(call, pred);
-	mutex_unlock(&filter_mutex);
-
-	return err;
-}
-
-int filter_add_subsystem_pred(struct event_subsystem *system,
-			      struct filter_pred *pred)
+static int filter_add_subsystem_pred(struct filter_parse_state *ps,
+				     struct event_subsystem *system,
+				     struct filter_pred *pred,
+				     char *filter_string)
 {
 	struct event_filter *filter = system->filter;
 	struct ftrace_event_call *call;
 
-	mutex_lock(&filter_mutex);
-
-	if (filter && filter->n_preds && !pred->compound) {
-		__filter_free_subsystem_preds(system);
-		filter = NULL;
-	}
-
-	if (!filter) {
-		system->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
-		if (!system->filter) {
-			mutex_unlock(&filter_mutex);
-			return -ENOMEM;
-		}
-		filter = system->filter;
+	if (!filter->preds) {
 		filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
 					GFP_KERNEL);
 
-		if (!filter->preds) {
-			kfree(system->filter);
-			system->filter = NULL;
-			mutex_unlock(&filter_mutex);
+		if (!filter->preds)
 			return -ENOMEM;
-		}
 	}
 
 	if (filter->n_preds == MAX_FILTER_PRED) {
-		mutex_unlock(&filter_mutex);
+		parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
 		return -ENOSPC;
 	}
 
@@ -424,97 +585,508 @@ int filter_add_subsystem_pred(struct event_subsystem *system,
 		if (strcmp(call->system, system->name))
 			continue;
 
-		err = __filter_add_pred(call, pred);
-		if (err == -ENOMEM) {
-			filter->preds[filter->n_preds] = NULL;
-			filter->n_preds--;
-			mutex_unlock(&filter_mutex);
+		err = filter_add_pred(ps, call, pred);
+		if (err) {
+			filter_free_subsystem_preds(system);
+			parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
 			return err;
 		}
+		replace_filter_string(call->filter, filter_string);
 	}
 
-	mutex_unlock(&filter_mutex);
-
 	return 0;
 }
 
-/*
- * The filter format can be
- *   - 0, which means remove all filter preds
- *   - [||/&&] <field> ==/!= <val>
- */
-int filter_parse(char **pbuf, struct filter_pred *pred)
+static void parse_init(struct filter_parse_state *ps,
+		       struct filter_op *ops,
+		       char *infix_string)
 {
-	char *tok, *val_str = NULL;
-	int tok_n = 0;
+	memset(ps, '\0', sizeof(*ps));
 
-	while ((tok = strsep(pbuf, " \n"))) {
-		if (tok_n == 0) {
-			if (!strcmp(tok, "0")) {
-				pred->clear = 1;
-				return 0;
-			} else if (!strcmp(tok, "&&")) {
-				pred->or = 0;
-				pred->compound = 1;
-			} else if (!strcmp(tok, "||")) {
-				pred->or = 1;
-				pred->compound = 1;
-			} else
-				pred->field_name = tok;
-			tok_n = 1;
-			continue;
-		}
-		if (tok_n == 1) {
-			if (!pred->field_name)
-				pred->field_name = tok;
-			else if (!strcmp(tok, "!="))
-				pred->not = 1;
-			else if (!strcmp(tok, "=="))
-				pred->not = 0;
-			else {
-				pred->field_name = NULL;
-				return -EINVAL;
-			}
-			tok_n = 2;
-			continue;
-		}
-		if (tok_n == 2) {
-			if (pred->compound) {
-				if (!strcmp(tok, "!="))
-					pred->not = 1;
-				else if (!strcmp(tok, "=="))
-					pred->not = 0;
-				else {
-					pred->field_name = NULL;
-					return -EINVAL;
-				}
-			} else {
-				val_str = tok;
-				break; /* done */
-			}
-			tok_n = 3;
-			continue;
-		}
-		if (tok_n == 3) {
-			val_str = tok;
-			break; /* done */
+	ps->infix.string = infix_string;
+	ps->infix.cnt = strlen(infix_string);
+	ps->ops = ops;
+
+	INIT_LIST_HEAD(&ps->opstack);
+	INIT_LIST_HEAD(&ps->postfix);
+}
+
+static char infix_next(struct filter_parse_state *ps)
+{
+	ps->infix.cnt--;
+
+	return ps->infix.string[ps->infix.tail++];
+}
+
+static char infix_peek(struct filter_parse_state *ps)
+{
+	if (ps->infix.tail == strlen(ps->infix.string))
+		return 0;
+
+	return ps->infix.string[ps->infix.tail];
+}
+
+static void infix_advance(struct filter_parse_state *ps)
+{
+	ps->infix.cnt--;
+	ps->infix.tail++;
+}
+
+static inline int is_precedence_lower(struct filter_parse_state *ps,
+				      int a, int b)
+{
+	return ps->ops[a].precedence < ps->ops[b].precedence;
+}
+
+static inline int is_op_char(struct filter_parse_state *ps, char c)
+{
+	int i;
+
+	for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
+		if (ps->ops[i].string[0] == c)
+			return 1;
+	}
+
+	return 0;
+}
+
+static int infix_get_op(struct filter_parse_state *ps, char firstc)
+{
+	char nextc = infix_peek(ps);
+	char opstr[3];
+	int i;
+
+	opstr[0] = firstc;
+	opstr[1] = nextc;
+	opstr[2] = '\0';
+
+	for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
+		if (!strcmp(opstr, ps->ops[i].string)) {
+			infix_advance(ps);
+			return ps->ops[i].id;
 		}
 	}
 
-	if (!val_str || !strlen(val_str)
-	    || strlen(val_str) >= MAX_FILTER_STR_VAL) {
-		pred->field_name = NULL;
+	opstr[1] = '\0';
+
+	for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
+		if (!strcmp(opstr, ps->ops[i].string))
+			return ps->ops[i].id;
+	}
+
+	return OP_NONE;
+}
+
+static inline void clear_operand_string(struct filter_parse_state *ps)
+{
+	memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL);
+	ps->operand.tail = 0;
+}
+
+static inline int append_operand_char(struct filter_parse_state *ps, char c)
+{
+	if (ps->operand.tail == MAX_FILTER_STR_VAL)
+		return -EINVAL;
+
+	ps->operand.string[ps->operand.tail++] = c;
+
+	return 0;
+}
+
+static int filter_opstack_push(struct filter_parse_state *ps, int op)
+{
+	struct opstack_op *opstack_op;
+
+	opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL);
+	if (!opstack_op)
+		return -ENOMEM;
+
+	opstack_op->op = op;
+	list_add(&opstack_op->list, &ps->opstack);
+
+	return 0;
+}
+
+static int filter_opstack_empty(struct filter_parse_state *ps)
+{
+	return list_empty(&ps->opstack);
+}
+
+static int filter_opstack_top(struct filter_parse_state *ps)
+{
+	struct opstack_op *opstack_op;
+
+	if (filter_opstack_empty(ps))
+		return OP_NONE;
+
+	opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
+
+	return opstack_op->op;
+}
+
+static int filter_opstack_pop(struct filter_parse_state *ps)
+{
+	struct opstack_op *opstack_op;
+	int op;
+
+	if (filter_opstack_empty(ps))
+		return OP_NONE;
+
+	opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
+	op = opstack_op->op;
+	list_del(&opstack_op->list);
+
+	kfree(opstack_op);
+
+	return op;
+}
+
+static void filter_opstack_clear(struct filter_parse_state *ps)
+{
+	while (!filter_opstack_empty(ps))
+		filter_opstack_pop(ps);
+}
+
+static char *curr_operand(struct filter_parse_state *ps)
+{
+	return ps->operand.string;
+}
+
+static int postfix_append_operand(struct filter_parse_state *ps, char *operand)
+{
+	struct postfix_elt *elt;
+
+	elt = kmalloc(sizeof(*elt), GFP_KERNEL);
+	if (!elt)
+		return -ENOMEM;
+
+	elt->op = OP_NONE;
+	elt->operand = kstrdup(operand, GFP_KERNEL);
+	if (!elt->operand) {
+		kfree(elt);
+		return -ENOMEM;
+	}
+
+	list_add_tail(&elt->list, &ps->postfix);
+
+	return 0;
+}
+
+static int postfix_append_op(struct filter_parse_state *ps, int op)
+{
+	struct postfix_elt *elt;
+
+	elt = kmalloc(sizeof(*elt), GFP_KERNEL);
+	if (!elt)
+		return -ENOMEM;
+
+	elt->op = op;
+	elt->operand = NULL;
+
+	list_add_tail(&elt->list, &ps->postfix);
+
+	return 0;
+}
+
+static void postfix_clear(struct filter_parse_state *ps)
+{
+	struct postfix_elt *elt;
+
+	while (!list_empty(&ps->postfix)) {
+		elt = list_first_entry(&ps->postfix, struct postfix_elt, list);
+		kfree(elt->operand);
+		list_del(&elt->list);
+	}
+}
+
+static int filter_parse(struct filter_parse_state *ps)
+{
+	int op, top_op;
+	char ch;
+
+	while ((ch = infix_next(ps))) {
+		if (isspace(ch))
+			continue;
+
+		if (is_op_char(ps, ch)) {
+			op = infix_get_op(ps, ch);
+			if (op == OP_NONE) {
+				parse_error(ps, FILT_ERR_INVALID_OP, 0);
+				return -EINVAL;
+			}
+
+			if (strlen(curr_operand(ps))) {
+				postfix_append_operand(ps, curr_operand(ps));
+				clear_operand_string(ps);
+			}
+
+			while (!filter_opstack_empty(ps)) {
+				top_op = filter_opstack_top(ps);
+				if (!is_precedence_lower(ps, top_op, op)) {
+					top_op = filter_opstack_pop(ps);
+					postfix_append_op(ps, top_op);
+					continue;
+				}
+				break;
+			}
+
+			filter_opstack_push(ps, op);
+			continue;
+		}
+
+		if (ch == '(') {
+			filter_opstack_push(ps, OP_OPEN_PAREN);
+			continue;
+		}
+
+		if (ch == ')') {
+			if (strlen(curr_operand(ps))) {
+				postfix_append_operand(ps, curr_operand(ps));
+				clear_operand_string(ps);
+			}
+
+			top_op = filter_opstack_pop(ps);
+			while (top_op != OP_NONE) {
+				if (top_op == OP_OPEN_PAREN)
+					break;
+				postfix_append_op(ps, top_op);
+				top_op = filter_opstack_pop(ps);
+			}
+			if (top_op == OP_NONE) {
+				parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
+				return -EINVAL;
+			}
+			continue;
+		}
+		if (append_operand_char(ps, ch)) {
+			parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
+			return -EINVAL;
+		}
+	}
+
+	if (strlen(curr_operand(ps)))
+		postfix_append_operand(ps, curr_operand(ps));
+
+	while (!filter_opstack_empty(ps)) {
+		top_op = filter_opstack_pop(ps);
+		if (top_op == OP_NONE)
+			break;
+		if (top_op == OP_OPEN_PAREN) {
+			parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
+			return -EINVAL;
+		}
+		postfix_append_op(ps, top_op);
+	}
+
+	return 0;
+}
+
+static struct filter_pred *create_pred(int op, char *operand1, char *operand2)
+{
+	struct filter_pred *pred;
+
+	pred = kzalloc(sizeof(*pred), GFP_KERNEL);
+	if (!pred)
+		return NULL;
+
+	pred->field_name = kstrdup(operand1, GFP_KERNEL);
+	if (!pred->field_name) {
+		kfree(pred);
+		return NULL;
+	}
+
+	strcpy(pred->str_val, operand2);
+	pred->str_len = strlen(operand2);
+
+	pred->op = op;
+
+	return pred;
+}
+
+static struct filter_pred *create_logical_pred(int op)
+{
+	struct filter_pred *pred;
+
+	pred = kzalloc(sizeof(*pred), GFP_KERNEL);
+	if (!pred)
+		return NULL;
+
+	pred->op = op;
+
+	return pred;
+}
+
+static int check_preds(struct filter_parse_state *ps)
+{
+	int n_normal_preds = 0, n_logical_preds = 0;
+	struct postfix_elt *elt;
+
+	list_for_each_entry(elt, &ps->postfix, list) {
+		if (elt->op == OP_NONE)
+			continue;
+
+		if (elt->op == OP_AND || elt->op == OP_OR) {
+			n_logical_preds++;
+			continue;
+		}
+		n_normal_preds++;
+	}
+
+	if (!n_normal_preds || n_logical_preds >= n_normal_preds) {
+		parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
 		return -EINVAL;
 	}
 
-	strcpy(pred->str_val, val_str);
-	pred->str_len = strlen(val_str);
+	return 0;
+}
 
-	pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);
-	if (!pred->field_name)
-		return -ENOMEM;
+static int replace_preds(struct event_subsystem *system,
+			 struct ftrace_event_call *call,
+			 struct filter_parse_state *ps,
+			 char *filter_string)
+{
+	char *operand1 = NULL, *operand2 = NULL;
+	struct filter_pred *pred;
+	struct postfix_elt *elt;
+	int err;
+
+	err = check_preds(ps);
+	if (err)
+		return err;
+
+	list_for_each_entry(elt, &ps->postfix, list) {
+		if (elt->op == OP_NONE) {
+			if (!operand1)
+				operand1 = elt->operand;
+			else if (!operand2)
+				operand2 = elt->operand;
+			else {
+				parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
+				return -EINVAL;
+			}
+			continue;
+		}
+
+		if (elt->op == OP_AND || elt->op == OP_OR) {
+			pred = create_logical_pred(elt->op);
+			if (call) {
+				err = filter_add_pred(ps, call, pred);
+				filter_free_pred(pred);
+			} else
+				err = filter_add_subsystem_pred(ps, system,
+							pred, filter_string);
+			if (err)
+				return err;
+
+			operand1 = operand2 = NULL;
+			continue;
+		}
+
+		if (!operand1 || !operand2) {
+			parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
+			return -EINVAL;
+		}
+
+		pred = create_pred(elt->op, operand1, operand2);
+		if (call) {
+			err = filter_add_pred(ps, call, pred);
+			filter_free_pred(pred);
+		} else
+			err = filter_add_subsystem_pred(ps, system, pred,
+							filter_string);
+		if (err)
+			return err;
+
+		operand1 = operand2 = NULL;
+	}
 
 	return 0;
 }
 
+int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
+{
+	int err;
+
+	struct filter_parse_state *ps;
+
+	mutex_lock(&filter_mutex);
+
+	if (!strcmp(strstrip(filter_string), "0")) {
+		filter_disable_preds(call);
+		remove_filter_string(call->filter);
+		mutex_unlock(&filter_mutex);
+		return 0;
+	}
+
+	ps = kzalloc(sizeof(*ps), GFP_KERNEL);
+	if (!ps)
+		return -ENOMEM;
+
+	filter_disable_preds(call);
+	replace_filter_string(call->filter, filter_string);
+
+	parse_init(ps, filter_ops, filter_string);
+	err = filter_parse(ps);
+	if (err) {
+		append_filter_err(ps, call->filter);
+		goto out;
+	}
+
+	err = replace_preds(NULL, call, ps, filter_string);
+	if (err)
+		append_filter_err(ps, call->filter);
+
+out:
+	filter_opstack_clear(ps);
+	postfix_clear(ps);
+	kfree(ps);
+
+	mutex_unlock(&filter_mutex);
+
+	return err;
+}
+
+int apply_subsystem_event_filter(struct event_subsystem *system,
+				 char *filter_string)
+{
+	int err;
+
+	struct filter_parse_state *ps;
+
+	mutex_lock(&filter_mutex);
+
+	if (!strcmp(strstrip(filter_string), "0")) {
+		filter_free_subsystem_preds(system);
+		remove_filter_string(system->filter);
+		mutex_unlock(&filter_mutex);
+		return 0;
+	}
+
+	ps = kzalloc(sizeof(*ps), GFP_KERNEL);
+	if (!ps)
+		return -ENOMEM;
+
+	filter_free_subsystem_preds(system);
+	replace_filter_string(system->filter, filter_string);
+
+	parse_init(ps, filter_ops, filter_string);
+	err = filter_parse(ps);
+	if (err) {
+		append_filter_err(ps, system->filter);
+		goto out;
+	}
+
+	err = replace_preds(system, NULL, ps, filter_string);
+	if (err)
+		append_filter_err(ps, system->filter);
+
+out:
+	filter_opstack_clear(ps);
+	postfix_clear(ps);
+	kfree(ps);
+
+	mutex_unlock(&filter_mutex);
+
+	return err;
+}