Hi again,
On 12/24/2014 02:12 AM, Tom Haynes wrote:
> From: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
>
> Signed-off-by: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
> Signed-off-by: Tom Haynes <Thomas.Haynes@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/pnfs.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 2d25670..fa00b56 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -1288,7 +1288,6 @@ pnfs_update_layout(struct inode *ino,
> struct nfs_client *clp = server->nfs_client;
> struct pnfs_layout_hdr *lo;
> struct pnfs_layout_segment *lseg = NULL;
> - bool first;
>
> if (!pnfs_enabled_sb(NFS_SERVER(ino)))
> goto out;
> @@ -1321,16 +1320,15 @@ pnfs_update_layout(struct inode *ino,
> if (pnfs_layoutgets_blocked(lo, 0))
> goto out_unlock;
> atomic_inc(&lo->plh_outstanding);
> -
> - first = list_empty(&lo->plh_layouts) ? true : false;
> spin_unlock(&ino->i_lock);
>
> - if (first) {
> + if (list_empty(&lo->plh_layouts)) {
> /* The lo must be on the clp list if there is any
> * chance of a CB_LAYOUTRECALL(FILE) coming in.
> */
> spin_lock(&clp->cl_lock);
> - list_add_tail(&lo->plh_layouts, &server->layouts);
> + if (list_empty(&lo->plh_layouts))
> + list_add_tail(&lo->plh_layouts, &server->layouts);
> spin_unlock(&clp->cl_lock);
> }
Do we really need to call list_empty() twice? Would there be a serious performance drawback if we removed the outer layer if condition and then always call list_empty() under the cl_lock?
Thanks,
Anna
>
>
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