On Tue, Mar 13, 2018 at 11:01 PM, Chengguang Xu <cgxu519@xxxxxxx> wrote:
> Do memory allocation first, so that avoid unnecessary
> initialization of newly allocated session in error case.
>
> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
> ---
>
> Changes since v1:
> - mds number can't be bigger than newmax, so delete that check.
> - kfree old session array after new one set to mdsc->sessions.
> - add newly allocated session to session array ater initialization.
> - modify commit log.
>
> fs/ceph/mds_client.c | 37 ++++++++++++++++++++-----------------
> 1 file changed, 20 insertions(+), 17 deletions(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index e932c06..47c0d92 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -468,6 +468,26 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
> s = kzalloc(sizeof(*s), GFP_NOFS);
> if (!s)
> return ERR_PTR(-ENOMEM);
> +
> + if (mds >= mdsc->max_sessions) {
> + int newmax = 1 << get_count_order(mds + 1);
> + struct ceph_mds_session **sa;
> + struct ceph_mds_session **old = mdsc->sessions;
> +
> + dout("%s: realloc to %d\n", __func__, newmax);
> + sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
> + if (!sa)
> + goto fail_realloc;
> +
> + if (old)
> + memcpy(sa, old, mdsc->max_sessions * sizeof(void *));
> +
> + mdsc->sessions = sa;
> + mdsc->max_sessions = newmax;
> + kfree(old);
> + }
> +
> + dout("%s: mds%d\n", __func__, mds);
> s->s_mdsc = mdsc;
> s->s_mds = mds;
> s->s_state = CEPH_MDS_SESSION_NEW;
> @@ -496,23 +516,6 @@ static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
> INIT_LIST_HEAD(&s->s_cap_releases);
> INIT_LIST_HEAD(&s->s_cap_flushing);
>
> - dout("register_session mds%d\n", mds);
> - if (mds >= mdsc->max_sessions) {
> - int newmax = 1 << get_count_order(mds+1);
> - struct ceph_mds_session **sa;
> -
> - dout("register_session realloc to %d\n", newmax);
> - sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
> - if (!sa)
> - goto fail_realloc;
> - if (mdsc->sessions) {
> - memcpy(sa, mdsc->sessions,
> - mdsc->max_sessions * sizeof(void *));
> - kfree(mdsc->sessions);
> - }
> - mdsc->sessions = sa;
> - mdsc->max_sessions = newmax;
> - }
> mdsc->sessions[mds] = s;
> atomic_inc(&mdsc->num_sessions);
> refcount_inc(&s->s_ref); /* one ref to sessions[], one to caller */
> --
> 1.8.3.1
>
Applied, thanks,
Yan, Zheng
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