nfsd/idmap: drop special request deferal in favour of improved default.

The idmap code manages request deferal by waiting for a reply from
userspace rather than putting the NFS request on a queue to be retried
from the start.
Now that the common deferal code does this there is no need for the
special code in idmap.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 11 insertions, 94 deletions

diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 808b33a4a090..f0695e815f0e 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -482,109 +482,26 @@ nfsd_idmap_shutdown(void)
         cache_unregister(&nametoid_cache);
 }
 
-/*
- * Deferred request handling
- */
-
-struct idmap_defer_req {
-       struct cache_req         req;
-       struct cache_deferred_req deferred_req;
-       wait_queue_head_t        waitq;
-       atomic_t                 count;
-};
-
-static inline void
-put_mdr(struct idmap_defer_req *mdr)
-{
-        if (atomic_dec_and_test(&mdr->count))
-                kfree(mdr);
-}
-
-static inline void
-get_mdr(struct idmap_defer_req *mdr)
-{
-        atomic_inc(&mdr->count);
-}
-
-static void
-idmap_revisit(struct cache_deferred_req *dreq, int toomany)
-{
-        struct idmap_defer_req *mdr =
-                container_of(dreq, struct idmap_defer_req, deferred_req);
-
-        wake_up(&mdr->waitq);
-        put_mdr(mdr);
-}
-
-static struct cache_deferred_req *
-idmap_defer(struct cache_req *req)
-{
-        struct idmap_defer_req *mdr =
-                container_of(req, struct idmap_defer_req, req);
-
-        mdr->deferred_req.revisit = idmap_revisit;
-        get_mdr(mdr);
-        return (&mdr->deferred_req);
-}
-
-static inline int
-do_idmap_lookup(struct ent *(*lookup_fn)(struct ent *), struct ent *key,
-                struct cache_detail *detail, struct ent **item,
-                struct idmap_defer_req *mdr)
-{
-        *item = lookup_fn(key);
-        if (!*item)
-                return -ENOMEM;
-        return cache_check(detail, &(*item)->h, &mdr->req);
-}
-
-static inline int
-do_idmap_lookup_nowait(struct ent *(*lookup_fn)(struct ent *),
-                        struct ent *key, struct cache_detail *detail,
-                        struct ent **item)
-{
-        int ret = -ENOMEM;
-
-        *item = lookup_fn(key);
-        if (!*item)
-                goto out_err;
-        ret = -ETIMEDOUT;
-        if (!test_bit(CACHE_VALID, &(*item)->h.flags)
-                        || (*item)->h.expiry_time < seconds_since_boot()
-                        || detail->flush_time > (*item)->h.last_refresh)
-                goto out_put;
-        ret = -ENOENT;
-        if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
-                goto out_put;
-        return 0;
-out_put:
-        cache_put(&(*item)->h, detail);
-out_err:
-        *item = NULL;
-        return ret;
-}
-
 static int
 idmap_lookup(struct svc_rqst *rqstp,
                 struct ent *(*lookup_fn)(struct ent *), struct ent *key,
                 struct cache_detail *detail, struct ent **item)
 {
-        struct idmap_defer_req *mdr;
         int ret;
 
-        mdr = kzalloc(sizeof(*mdr), GFP_KERNEL);
-        if (!mdr)
+        *item = lookup_fn(key);
+        if (!*item)
                 return -ENOMEM;
-        atomic_set(&mdr->count, 1);
-        init_waitqueue_head(&mdr->waitq);
-        mdr->req.defer = idmap_defer;
-        ret = do_idmap_lookup(lookup_fn, key, detail, item, mdr);
-        if (ret == -EAGAIN) {
-                wait_event_interruptible_timeout(mdr->waitq,
-                        test_bit(CACHE_VALID, &(*item)->h.flags), 1 * HZ);
-                ret = do_idmap_lookup_nowait(lookup_fn, key, detail, item);
+ retry:
+        ret = cache_check(detail, &(*item)->h, &rqstp->rq_chandle);
+
+        if (ret == -ETIMEDOUT) {
+                struct ent *prev_item = *item;
+                *item = lookup_fn(key);
+                if (*item != prev_item)
+                        goto retry;
+                cache_put(&(*item)->h, detail);
         }
-        put_mdr(mdr);
         return ret;
 }