staging: lustre: obdclass: change spinlock of key to rwlock

Most of the time, keys are never changed. So rwlock might be
better for the concurrency of key read.

Signed-off-by: Li Xi <lixi@ddn.com>
Signed-off-by: Gu Zheng <gzheng@ddn.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6800
Reviewed-on: http://review.whamcloud.com/15558
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index 3de7dc0..5f7ba25 100644 (file)
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -1327,7 +1327,7 @@ enum {
 
 static struct lu_context_key *lu_keys[LU_CONTEXT_KEY_NR] = { NULL, };
 
-static DEFINE_SPINLOCK(lu_keys_guard);
+static DEFINE_RWLOCK(lu_keys_guard);
 static atomic_t lu_key_initing_cnt = ATOMIC_INIT(0);
 
 /**
@@ -1351,7 +1351,7 @@ int lu_context_key_register(struct lu_context_key *key)
        LASSERT(key->lct_tags != 0);
 
        result = -ENFILE;
-       spin_lock(&lu_keys_guard);
+       write_lock(&lu_keys_guard);
        for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
                if (!lu_keys[i]) {
                        key->lct_index = i;
@@ -1363,7 +1363,7 @@ int lu_context_key_register(struct lu_context_key *key)
                        break;
                }
        }
-       spin_unlock(&lu_keys_guard);
+       write_unlock(&lu_keys_guard);
        return result;
 }
 EXPORT_SYMBOL(lu_context_key_register);
@@ -1397,7 +1397,7 @@ void lu_context_key_degister(struct lu_context_key *key)
        lu_context_key_quiesce(key);
 
        ++key_set_version;
-       spin_lock(&lu_keys_guard);
+       write_lock(&lu_keys_guard);
        key_fini(&lu_shrink_env.le_ctx, key->lct_index);
 
        /**
@@ -1405,18 +1405,18 @@ void lu_context_key_degister(struct lu_context_key *key)
         * run lu_context_key::lct_fini() method.
         */
        while (atomic_read(&key->lct_used) > 1) {
-               spin_unlock(&lu_keys_guard);
+               write_unlock(&lu_keys_guard);
                CDEBUG(D_INFO, "%s: \"%s\" %p, %d\n",
                       __func__, module_name(key->lct_owner),
                       key, atomic_read(&key->lct_used));
                schedule();
-               spin_lock(&lu_keys_guard);
+               write_lock(&lu_keys_guard);
        }
        if (lu_keys[key->lct_index]) {
                lu_keys[key->lct_index] = NULL;
                lu_ref_fini(&key->lct_reference);
        }
-       spin_unlock(&lu_keys_guard);
+       write_unlock(&lu_keys_guard);
 
        LASSERTF(atomic_read(&key->lct_used) == 1,
                 "key has instances: %d\n",
@@ -1536,7 +1536,7 @@ void lu_context_key_quiesce(struct lu_context_key *key)
                /*
                 * XXX memory barrier has to go here.
                 */
-               spin_lock(&lu_keys_guard);
+               write_lock(&lu_keys_guard);
                key->lct_tags |= LCT_QUIESCENT;
 
                /**
@@ -1544,19 +1544,19 @@ void lu_context_key_quiesce(struct lu_context_key *key)
                 * have completed.
                 */
                while (atomic_read(&lu_key_initing_cnt) > 0) {
-                       spin_unlock(&lu_keys_guard);
+                       write_unlock(&lu_keys_guard);
                        CDEBUG(D_INFO, "%s: \"%s\" %p, %d (%d)\n",
                               __func__,
                               module_name(key->lct_owner),
                               key, atomic_read(&key->lct_used),
                        atomic_read(&lu_key_initing_cnt));
                        schedule();
-                       spin_lock(&lu_keys_guard);
+                       write_lock(&lu_keys_guard);
                }
 
                list_for_each_entry(ctx, &lu_context_remembered, lc_remember)
                        key_fini(ctx, key->lct_index);
-               spin_unlock(&lu_keys_guard);
+               write_unlock(&lu_keys_guard);
                ++key_set_version;
        }
 }
@@ -1594,9 +1594,9 @@ static int keys_fill(struct lu_context *ctx)
         * An atomic_t variable is still used, in order not to reacquire the
         * lock when decrementing the counter.
         */
-       spin_lock(&lu_keys_guard);
+       read_lock(&lu_keys_guard);
        atomic_inc(&lu_key_initing_cnt);
-       spin_unlock(&lu_keys_guard);
+       read_unlock(&lu_keys_guard);
 
        LINVRNT(ctx->lc_value);
        for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
@@ -1665,9 +1665,9 @@ int lu_context_init(struct lu_context *ctx, __u32 tags)
        ctx->lc_state = LCS_INITIALIZED;
        ctx->lc_tags = tags;
        if (tags & LCT_REMEMBER) {
-               spin_lock(&lu_keys_guard);
+               write_lock(&lu_keys_guard);
                list_add(&ctx->lc_remember, &lu_context_remembered);
-               spin_unlock(&lu_keys_guard);
+               write_unlock(&lu_keys_guard);
        } else {
                INIT_LIST_HEAD(&ctx->lc_remember);
        }
@@ -1693,10 +1693,10 @@ void lu_context_fini(struct lu_context *ctx)
                keys_fini(ctx);
 
        } else { /* could race with key degister */
-               spin_lock(&lu_keys_guard);
+               write_lock(&lu_keys_guard);
                keys_fini(ctx);
                list_del_init(&ctx->lc_remember);
-               spin_unlock(&lu_keys_guard);
+               write_unlock(&lu_keys_guard);
        }
 }
 EXPORT_SYMBOL(lu_context_fini);
@@ -1724,7 +1724,7 @@ void lu_context_exit(struct lu_context *ctx)
                for (i = 0; i < ARRAY_SIZE(lu_keys); ++i) {
                        /* could race with key quiescency */
                        if (ctx->lc_tags & LCT_REMEMBER)
-                               spin_lock(&lu_keys_guard);
+                               read_lock(&lu_keys_guard);
                        if (ctx->lc_value[i]) {
                                struct lu_context_key *key;
 
@@ -1734,7 +1734,7 @@ void lu_context_exit(struct lu_context *ctx)
                                                      key, ctx->lc_value[i]);
                        }
                        if (ctx->lc_tags & LCT_REMEMBER)
-                               spin_unlock(&lu_keys_guard);
+                               read_unlock(&lu_keys_guard);
                }
        }
 }