These changes are a raw update to a vanilla kernel 4.1.10, with the

[kvmfornfv.git] / kernel / drivers / md / raid5.c

diff --git a/kernel/drivers/md/raid5.c b/kernel/drivers/md/raid5.c
index 47413f7..a90d587 100644 (file)
--- a/kernel/drivers/md/raid5.c
+++ b/kernel/drivers/md/raid5.c
@@ -2153,6 +2153,9 @@ static int resize_stripes(struct r5conf *conf, int newsize)
        if (!sc)
                return -ENOMEM;
 
+       /* Need to ensure auto-resizing doesn't interfere */
+       mutex_lock(&conf->cache_size_mutex);
+
        for (i = conf->max_nr_stripes; i; i--) {
                nsh = alloc_stripe(sc, GFP_KERNEL);
                if (!nsh)
@@ -2169,6 +2172,7 @@ static int resize_stripes(struct r5conf *conf, int newsize)
                        kmem_cache_free(sc, nsh);
                }
                kmem_cache_destroy(sc);
+               mutex_unlock(&conf->cache_size_mutex);
                return -ENOMEM;
        }
        /* Step 2 - Must use GFP_NOIO now.
@@ -2215,6 +2219,7 @@ static int resize_stripes(struct r5conf *conf, int newsize)
        } else
                err = -ENOMEM;
 
+       mutex_unlock(&conf->cache_size_mutex);
        /* Step 4, return new stripes to service */
        while(!list_empty(&newstripes)) {
                nsh = list_entry(newstripes.next, struct stripe_head, lru);
@@ -2242,7 +2247,7 @@ static int resize_stripes(struct r5conf *conf, int newsize)
 static int drop_one_stripe(struct r5conf *conf)
 {
        struct stripe_head *sh;
-       int hash = (conf->max_nr_stripes - 1) % NR_STRIPE_HASH_LOCKS;
+       int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
 
        spin_lock_irq(conf->hash_locks + hash);
        sh = get_free_stripe(conf, hash);
@@ -5848,12 +5853,14 @@ static void raid5d(struct md_thread *thread)
        pr_debug("%d stripes handled\n", handled);
 
        spin_unlock_irq(&conf->device_lock);
-       if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state)) {
+       if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
+           mutex_trylock(&conf->cache_size_mutex)) {
                grow_one_stripe(conf, __GFP_NOWARN);
                /* Set flag even if allocation failed.  This helps
                 * slow down allocation requests when mem is short
                 */
                set_bit(R5_DID_ALLOC, &conf->cache_state);
+               mutex_unlock(&conf->cache_size_mutex);
        }
 
        async_tx_issue_pending_all();
@@ -5885,18 +5892,22 @@ raid5_set_cache_size(struct mddev *mddev, int size)
                return -EINVAL;
 
        conf->min_nr_stripes = size;
+       mutex_lock(&conf->cache_size_mutex);
        while (size < conf->max_nr_stripes &&
               drop_one_stripe(conf))
                ;
+       mutex_unlock(&conf->cache_size_mutex);
 
 
        err = md_allow_write(mddev);
        if (err)
                return err;
 
+       mutex_lock(&conf->cache_size_mutex);
        while (size > conf->max_nr_stripes)
                if (!grow_one_stripe(conf, GFP_KERNEL))
                        break;
+       mutex_unlock(&conf->cache_size_mutex);
 
        return 0;
 }
@@ -6363,11 +6374,19 @@ static unsigned long raid5_cache_scan(struct shrinker *shrink,
                                      struct shrink_control *sc)
 {
        struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
-       int ret = 0;
-       while (ret < sc->nr_to_scan) {
-               if (drop_one_stripe(conf) == 0)
-                       return SHRINK_STOP;
-               ret++;
+       unsigned long ret = SHRINK_STOP;
+
+       if (mutex_trylock(&conf->cache_size_mutex)) {
+               ret= 0;
+               while (ret < sc->nr_to_scan &&
+                      conf->max_nr_stripes > conf->min_nr_stripes) {
+                       if (drop_one_stripe(conf) == 0) {
+                               ret = SHRINK_STOP;
+                               break;
+                       }
+                       ret++;
+               }
+               mutex_unlock(&conf->cache_size_mutex);
        }
        return ret;
 }
@@ -6436,6 +6455,7 @@ static struct r5conf *setup_conf(struct mddev *mddev)
                goto abort;
        spin_lock_init(&conf->device_lock);
        seqcount_init(&conf->gen_lock);
+       mutex_init(&conf->cache_size_mutex);
        init_waitqueue_head(&conf->wait_for_stripe);
        init_waitqueue_head(&conf->wait_for_overlap);
        INIT_LIST_HEAD(&conf->handle_list);