[PATCH v3 2/2] fs/lock: Rearrange ops in flock syscall.

[Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>]

The previous patch added flock_translate_cmd() in flock syscall.
The test and the other one for LOCK_MAND do not depend on struct
fd and are cheaper, so we can put them at the top and defer
fdget() after that.

Also, we can remove the unlock variable and use type instead.
While at it, we fix this checkpatch error.

  CHECK: spaces preferred around that '|' (ctx:VxV)
  #45: FILE: fs/locks.c:2099:
  +	if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
   	                                                     ^

Finally, we can move the can_sleep part just before we use it.

Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
---
 fs/locks.c | 43 +++++++++++++++++++------------------------
 1 file changed, 19 insertions(+), 24 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index b134eaefd7d6..c266cfdc3291 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2083,20 +2083,9 @@ EXPORT_SYMBOL(locks_lock_inode_wait);
  */
 SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
 {
-	int can_sleep, error, unlock, type;
-	struct fd f = fdget(fd);
+	int can_sleep, error, type;
 	struct file_lock fl;
-
-	error = -EBADF;
-	if (!f.file)
-		goto out;
-
-	can_sleep = !(cmd & LOCK_NB);
-	cmd &= ~LOCK_NB;
-	unlock = (cmd == LOCK_UN);
-
-	if (!unlock && !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
-		goto out_putf;
+	struct fd f;
 
 	/*
 	 * LOCK_MAND locks were broken for a long time in that they never
@@ -2108,35 +2097,41 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
 	 */
 	if (cmd & LOCK_MAND) {
 		pr_warn_once("Attempt to set a LOCK_MAND lock via flock(2). This support has been removed and the request ignored.\n");
-		error = 0;
-		goto out_putf;
+		return 0;
 	}
 
-	type = flock_translate_cmd(cmd);
-	if (type < 0) {
-		error = type;
+	type = flock_translate_cmd(cmd & ~LOCK_NB);
+	if (type < 0)
+		return type;
+
+	error = -EBADF;
+	f = fdget(fd);
+	if (!f.file)
+		return error;
+
+	if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ | FMODE_WRITE)))
 		goto out_putf;
-	}
 
 	flock_make_lock(f.file, &fl, type);
 
-	if (can_sleep)
-		fl.fl_flags |= FL_SLEEP;
-
 	error = security_file_lock(f.file, fl.fl_type);
 	if (error)
 		goto out_putf;
 
+	can_sleep = !(cmd & LOCK_NB);
+	if (can_sleep)
+		fl.fl_flags |= FL_SLEEP;
+
 	if (f.file->f_op->flock)
 		error = f.file->f_op->flock(f.file,
-					  (can_sleep) ? F_SETLKW : F_SETLK,
+					    (can_sleep) ? F_SETLKW : F_SETLK,
 					    &fl);
 	else
 		error = locks_lock_file_wait(f.file, &fl);
 
  out_putf:
 	fdput(f);
- out:
+
 	return error;
 }
 
-- 
2.30.2