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Re: [RFC PATCH 1/1] cleanup: use bool as return type for rwsem_is_locked

To: Dave Chinner <david@xxxxxxxxxxxxx>, Pranith Kumar <pranith@xxxxxxxxxx>
Subject: Re: [RFC PATCH 1/1] cleanup: use bool as return type for rwsem_is_locked
From: Pranith Kumar <bobby.prani@xxxxxxxxx>
Date: Fri, 06 Jun 2014 20:59:50 -0400
Cc: peterz@xxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, tim.c.chen@xxxxxxxxxxxxxxx, davidlohr@xxxxxx, mingo@xxxxxxxxxx, xfs@xxxxxxxxxxx
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On 06/06/2014 08:18 PM, Dave Chinner wrote:
> On Fri, Jun 06, 2014 at 02:11:18PM -0400, Pranith Kumar wrote:
>> On 06/06/2014 01:53 PM, Pranith Kumar wrote:
>>> On Fri, Jun 6, 2014 at 3:35 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>>>>
>>>> Now in general, I don't particularly like such superfluous changes, so
>>>> unless you can show that GCC actually generates better code, I'd prefer
>>>> to keep things as they are.
>>>
>>> Fixed and checked the assembly. It saves us 2 bytes of code, not much. I am 
>>> not sure if that is worth it :(
>>>
>>> use bool as the return type for rwsem_is_locked() instead of int
>>>

> 
> If you are going to change the return type to bool, then you should
> also remove the manual "!!" conversions to a boolean return and let
> the compiler do it in the most optimal way.
> 
 
Agreed, please find patch below:

change return type to bool to follow rwsem_is_locked()

Signed-off-by: Pranith Kumar <bobby.prani@xxxxxxxxx>
---
 fs/xfs/xfs_inode.c | 8 ++++----
 fs/xfs/xfs_inode.h | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index a6115fe..c02ac49 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -285,25 +285,25 @@ xfs_ilock_demote(
 }
 
 #if defined(DEBUG) || defined(XFS_WARN)
-int
+bool
 xfs_isilocked(
        xfs_inode_t             *ip,
        uint                    lock_flags)
 {
        if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
                if (!(lock_flags & XFS_ILOCK_SHARED))
-                       return !!ip->i_lock.mr_writer;
+                       return !(ip->i_lock.mr_writer == 0);
                return rwsem_is_locked(&ip->i_lock.mr_lock);
        }
 
        if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
                if (!(lock_flags & XFS_IOLOCK_SHARED))
-                       return !!ip->i_iolock.mr_writer;
+                       return !(ip->i_iolock.mr_writer == 0);
                return rwsem_is_locked(&ip->i_iolock.mr_lock);
        }
 
        ASSERT(0);
-       return 0;
+       return false;
 }
 #endif
 
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index f72bffa..efebed6 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -346,7 +346,7 @@ void                xfs_ilock(xfs_inode_t *, uint);
 int            xfs_ilock_nowait(xfs_inode_t *, uint);
 void           xfs_iunlock(xfs_inode_t *, uint);
 void           xfs_ilock_demote(xfs_inode_t *, uint);
-int            xfs_isilocked(xfs_inode_t *, uint);
+bool           xfs_isilocked(xfs_inode_t *, uint);
 uint           xfs_ilock_data_map_shared(struct xfs_inode *);
 uint           xfs_ilock_attr_map_shared(struct xfs_inode *);
 int            xfs_ialloc(struct xfs_trans *, xfs_inode_t *, umode_t,
-- 
1.9.1

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