bcache: remove 'int n' from parameter list of bch_bucket_alloc_set()

The parameter 'int n' from bch_bucket_alloc_set() is not cleared
defined. From the code comments n is the number of buckets to alloc, but
from the code itself 'n' is the maximum cache to iterate. Indeed all the
locations where bch_bucket_alloc_set() is called, 'n' is alwasy 1.

This patch removes the confused and unnecessary 'int n' from parameter
list of  bch_bucket_alloc_set(), and explicitly allocates only 1 bucket
for its caller.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index 52035a7..4493ff5 100644 (file)
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -49,7 +49,7 @@
  *
  * bch_bucket_alloc() allocates a single bucket from a specific cache.
  *
- * bch_bucket_alloc_set() allocates one or more buckets from different caches
+ * bch_bucket_alloc_set() allocates one  bucket from different caches
  * out of a cache set.
  *
  * free_some_buckets() drives all the processes described above. It's called
@@ -488,34 +488,29 @@ void bch_bucket_free(struct cache_set *c, struct bkey *k)
 }
 
 int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
-                          struct bkey *k, int n, bool wait)
+                          struct bkey *k, bool wait)
 {
-       int i;
+       struct cache *ca;
+       long b;
 
        /* No allocation if CACHE_SET_IO_DISABLE bit is set */
        if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags)))
                return -1;
 
        lockdep_assert_held(&c->bucket_lock);
-       BUG_ON(!n || n > c->caches_loaded || n > MAX_CACHES_PER_SET);
 
        bkey_init(k);
 
-       /* sort by free space/prio of oldest data in caches */
-
-       for (i = 0; i < n; i++) {
-               struct cache *ca = c->cache_by_alloc[i];
-               long b = bch_bucket_alloc(ca, reserve, wait);
+       ca = c->cache_by_alloc[0];
+       b = bch_bucket_alloc(ca, reserve, wait);
+       if (b == -1)
+               goto err;
 
-               if (b == -1)
-                       goto err;
+       k->ptr[0] = MAKE_PTR(ca->buckets[b].gen,
+                            bucket_to_sector(c, b),
+                            ca->sb.nr_this_dev);
 
-               k->ptr[i] = MAKE_PTR(ca->buckets[b].gen,
-                               bucket_to_sector(c, b),
-                               ca->sb.nr_this_dev);
-
-               SET_KEY_PTRS(k, i + 1);
-       }
+       SET_KEY_PTRS(k, 1);
 
        return 0;
 err:
@@ -525,12 +520,12 @@ err:
 }
 
 int bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
-                        struct bkey *k, int n, bool wait)
+                        struct bkey *k, bool wait)
 {
        int ret;
 
        mutex_lock(&c->bucket_lock);
-       ret = __bch_bucket_alloc_set(c, reserve, k, n, wait);
+       ret = __bch_bucket_alloc_set(c, reserve, k, wait);
        mutex_unlock(&c->bucket_lock);
        return ret;
 }
@@ -638,7 +633,7 @@ bool bch_alloc_sectors(struct cache_set *c,
 
                spin_unlock(&c->data_bucket_lock);
 
-               if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, wait))
+               if (bch_bucket_alloc_set(c, watermark, &alloc.key, wait))
                        return false;
 
                spin_lock(&c->data_bucket_lock);

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 4fd03d2..5ff6e95 100644 (file)
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -994,9 +994,9 @@ void bch_bucket_free(struct cache_set *c, struct bkey *k);
 
 long bch_bucket_alloc(struct cache *ca, unsigned int reserve, bool wait);
 int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
-                          struct bkey *k, int n, bool wait);
+                          struct bkey *k, bool wait);
 int bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
-                        struct bkey *k, int n, bool wait);
+                        struct bkey *k, bool wait);
 bool bch_alloc_sectors(struct cache_set *c, struct bkey *k,
                       unsigned int sectors, unsigned int write_point,
                       unsigned int write_prio, bool wait);

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index ae7611f..e2bd034 100644 (file)
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1091,7 +1091,7 @@ struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
 
        mutex_lock(&c->bucket_lock);
 retry:
-       if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, wait))
+       if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, wait))
                goto err;
 
        bkey_put(c, &k.key);

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index d34495d..b4176b8 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -486,7 +486,7 @@ static int __uuid_write(struct cache_set *c)
        closure_init_stack(&cl);
        lockdep_assert_held(&bch_register_lock);
 
-       if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, true))
+       if (bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, true))
                return 1;
 
        size =  meta_bucket_pages(&c->sb) * PAGE_SECTORS;