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authorAndreas Gruenbacher <agruenba@redhat.com>2017-02-22 01:19:10 +0300
committerBob Peterson <rpeterso@redhat.com>2017-04-03 16:14:41 +0300
commit0a52aba7c2168636fc71635cf3ccb92a79a96c38 (patch)
treea6d611d27d4c2a91e894165e71f31488e442ccd8 /fs/gfs2/glock.c
parentc369898759e0e143a513d022121290370f001d01 (diff)
downloadlinux-0a52aba7c2168636fc71635cf3ccb92a79a96c38.tar.xz
gfs2: Switch to rhashtable_lookup_get_insert_fast
Switch from rhashtable_lookup_insert_fast + rhashtable_lookup_fast to rhashtable_lookup_get_insert_fast, which is cleaner and avoids an extra rhashtable lookup. At the same time, turn the retry loop in gfs2_glock_get into an infinite loop. The lookup or insert will eventually succeed, usually very fast, but there is no reason to give up trying at a fixed number of iterations. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Diffstat (limited to 'fs/gfs2/glock.c')
-rw-r--r--fs/gfs2/glock.c45
1 files changed, 21 insertions, 24 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 35f3b0a1d81b..9e81219692c4 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -655,10 +655,10 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
struct lm_lockname name = { .ln_number = number,
.ln_type = glops->go_type,
.ln_sbd = sdp };
- struct gfs2_glock *gl, *tmp = NULL;
+ struct gfs2_glock *gl, *tmp;
struct address_space *mapping;
struct kmem_cache *cachep;
- int ret, tries = 0;
+ int ret = 0;
rcu_read_lock();
gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
@@ -723,35 +723,32 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
}
again:
- ret = rhashtable_lookup_insert_fast(&gl_hash_table, &gl->gl_node,
- ht_parms);
- if (ret == 0) {
+ rcu_read_lock();
+ tmp = rhashtable_lookup_get_insert_fast(&gl_hash_table, &gl->gl_node,
+ ht_parms);
+ if (!tmp) {
*glp = gl;
- return 0;
+ goto out;
}
-
- if (ret == -EEXIST) {
- ret = 0;
- rcu_read_lock();
- tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
- if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {
- if (++tries < 100) {
- rcu_read_unlock();
- cond_resched();
- goto again;
- }
- tmp = NULL;
- ret = -ENOMEM;
- }
- rcu_read_unlock();
- } else {
- WARN_ON_ONCE(ret);
+ if (IS_ERR(tmp)) {
+ ret = PTR_ERR(tmp);
+ goto out_free;
+ }
+ if (lockref_get_not_dead(&tmp->gl_lockref)) {
+ *glp = tmp;
+ goto out_free;
}
+ rcu_read_unlock();
+ cond_resched();
+ goto again;
+
+out_free:
kfree(gl->gl_lksb.sb_lvbptr);
kmem_cache_free(cachep, gl);
atomic_dec(&sdp->sd_glock_disposal);
- *glp = tmp;
+out:
+ rcu_read_unlock();
return ret;
}