jit: Kill compile lock from 'struct compilation_unit'

This patch re-implements the 'struct compilation_unit' parts of commit 4c197c5
("jit: Kill "compile lock" locking primitive") without breaking lusearch.

Signed-off-by: Pekka Enberg <penberg@kernel.org>

2 files changed, 26 insertions, 5 deletions

diff --git a/include/jit/compilation-unit.h b/include/jit/compilation-unit.h
index 42c4eb02..c5a6c5fa 100644
--- a/include/jit/compilation-unit.h
+++ b/include/jit/compilation-unit.h
@@ -10,7 +10,6 @@
 #include "lib/list.h"
 #include "lib/radix-tree.h"
 #include "lib/stack.h"
-#include "lib/compile-lock.h"
 
 #include "vm/static.h"
 #include "vm/types.h"
@@ -25,6 +24,13 @@ struct vm_method;
 struct insn;
 enum machine_reg;
 
+enum compilation_state {
+	COMPILATION_STATE_INITIAL,
+	COMPILATION_STATE_COMPILING,
+	COMPILATION_STATE_COMPILED,
+	COMPILATION_STATE_ERROR,
+};
+
 struct compilation_unit {
 	struct vm_method *method;
 	unsigned long nr_bb;
@@ -43,7 +49,11 @@ struct compilation_unit {
 	/* Contains the number of uses of any bytecode within the method */
 	uint16_t bytecode_stats[NR_OPCS];
 
-	struct compile_lock compile_lock;
+	/* Mutex that protects ->state  */
+	pthread_mutex_t compile_mutex;
+
+	/* See enum compilation_state for values */
+	unsigned long state;
 
 	pthread_mutex_t mutex;
 
@@ -170,6 +180,18 @@ static inline void *cu_ic_entry_point(struct compilation_unit *cu)
 	return cu->ic_entry_point;
 }
 
+unsigned long compilation_unit_get_state(struct compilation_unit *cu);
+
+static inline bool compilation_unit_is_compiled(struct compilation_unit *cu)
+{
+	/* Optimistic unlocked check */
+	if (cu->state == COMPILATION_STATE_COMPILED)
+		return true;
+
+	/* Slowpath */
+	return compilation_unit_get_state(cu) == COMPILATION_STATE_COMPILED;
+}
+
 struct compilation_unit *compilation_unit_alloc(struct vm_method *);
 int init_stack_slots(struct compilation_unit *cu);
 void free_compilation_unit(struct compilation_unit *);
diff --git a/include/vm/method.h b/include/vm/method.h
index 8431b452..d938701a 100644
--- a/include/vm/method.h
+++ b/include/vm/method.h
@@ -156,8 +156,7 @@ static inline bool vm_method_is_special(struct vm_method *vmm)
 
 static inline bool vm_method_is_compiled(struct vm_method *vmm)
 {
-	return 	compile_lock_get_status(&vmm->compilation_unit->compile_lock)
-		== STATUS_COMPILED_OK;
+	return compilation_unit_is_compiled(vmm->compilation_unit);
 }
 
 static inline enum vm_type method_return_type(struct vm_method *method)
@@ -186,7 +185,7 @@ static inline void *vm_method_call_ptr(struct vm_method *vmm)
 {
 	void *result;
 
-	if (compile_lock_get_status(&vmm->compilation_unit->compile_lock) == STATUS_COMPILED_OK)
+	if (vm_method_is_compiled(vmm))
 		result = vm_method_entry_point(vmm);
 	else
 		result = vm_method_trampoline_ptr(vmm);