[PATCH 2/2] trace_syscalls: cleanup: check syscall_nr with syscall_nr_to_meta

[Dmitry Safonov]

As syscall_nr_to_meta already checks for
(syscall_nr < 0 || syscall_nr >= NR_syscalls) - remove this checkups.

Signed-off-by: Dmitry Safonov <0x7f454c46@xxxxxxxxx>
---
 kernel/trace/trace_syscalls.c | 30 ++++++++++--------------------
 1 file changed, 10 insertions(+), 20 deletions(-)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index b9d4c3cc60aeba..7dc58306de1a3f 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -305,7 +305,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 	int size;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
 		return;
 
 	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
@@ -316,10 +317,6 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
-	sys_data = syscall_nr_to_meta(syscall_nr);
-	if (!sys_data)
-		return;
-
 	size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
 
 	local_save_flags(irq_flags);
@@ -352,7 +349,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
 	int syscall_nr;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
 		return;
 
 	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
@@ -363,10 +361,6 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
 	if (trace_trigger_soft_disabled(trace_file))
 		return;
 
-	sys_data = syscall_nr_to_meta(syscall_nr);
-	if (!sys_data)
-		return;
-
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
@@ -556,15 +550,13 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 	int size;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
-		return;
-	if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
-		return;
-
 	sys_data = syscall_nr_to_meta(syscall_nr);
 	if (!sys_data)
 		return;
 
+	if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
+		return;
+
 	head = this_cpu_ptr(sys_data->enter_event->perf_events);
 	if (hlist_empty(head))
 		return;
@@ -630,15 +622,13 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 	int size;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
-		return;
-	if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
-		return;
-
 	sys_data = syscall_nr_to_meta(syscall_nr);
 	if (!sys_data)
 		return;
 
+	if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
+		return;
+
 	head = this_cpu_ptr(sys_data->exit_event->perf_events);
 	if (hlist_empty(head))
 		return;
-- 
2.6.2

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