[PATCH] ext4: convert swap_inode_data() over to use swap() on most of the fields

[PATCH] ext4: convert swap_inode_data() over to use swap() on most of the fields

[Jeff Layton]

From: Jeff Layton <jlayton@redhat.com>

For some odd reason, it forces a byte-by-byte copy of each field. A
plain old swap() on most of these fields would be more efficient. We
do need to retain the memswap of i_data however as that field is an array.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ioctl.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 0c21e22acd74..3f76a9004e43 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -64,18 +64,16 @@ static void swap_inode_data(struct inode *inode1, struct inode *inode2)
 	ei1 = EXT4_I(inode1);
 	ei2 = EXT4_I(inode2);
 
-	memswap(&inode1->i_flags, &inode2->i_flags, sizeof(inode1->i_flags));
-	memswap(&inode1->i_version, &inode2->i_version,
-		  sizeof(inode1->i_version));
-	memswap(&inode1->i_blocks, &inode2->i_blocks,
-		  sizeof(inode1->i_blocks));
-	memswap(&inode1->i_bytes, &inode2->i_bytes, sizeof(inode1->i_bytes));
-	memswap(&inode1->i_atime, &inode2->i_atime, sizeof(inode1->i_atime));
-	memswap(&inode1->i_mtime, &inode2->i_mtime, sizeof(inode1->i_mtime));
+	swap(inode1->i_flags, inode2->i_flags);
+	swap(inode1->i_version, inode2->i_version);
+	swap(inode1->i_blocks, inode2->i_blocks);
+	swap(inode1->i_bytes, inode2->i_bytes);
+	swap(inode1->i_atime, inode2->i_atime);
+	swap(inode1->i_mtime, inode2->i_mtime);
 
 	memswap(ei1->i_data, ei2->i_data, sizeof(ei1->i_data));
-	memswap(&ei1->i_flags, &ei2->i_flags, sizeof(ei1->i_flags));
-	memswap(&ei1->i_disksize, &ei2->i_disksize, sizeof(ei1->i_disksize));
+	swap(ei1->i_flags, ei2->i_flags);
+	swap(ei1->i_disksize, ei2->i_disksize);
 	ext4_es_remove_extent(inode1, 0, EXT_MAX_BLOCKS);
 	ext4_es_remove_extent(inode2, 0, EXT_MAX_BLOCKS);
 
-- 
2.13.0

Re: [PATCH] ext4: convert swap_inode_data() over to use swap() on most of the fields

[Theodore Ts'o]

On Wed, Jul 05, 2017 at 12:32:07PM -0400, Jeff Layton wrote:
> From: Jeff Layton <jlayton@redhat.com>
> 
> For some odd reason, it forces a byte-by-byte copy of each field. A
> plain old swap() on most of these fields would be more efficient. We
> do need to retain the memswap of i_data however as that field is an array.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> Reviewed-by: Jan Kara <jack@suse.cz>

Thanks, applied.

					- Ted