[PATCH v1 01/14] bcache: remove 'int n' from parameter list of bch_bucket_alloc_set()

colyli
2020-08-15T22:24:07Z

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>
---
drivers/md/bcache/alloc.c | 35 +++++++++++++++--------------------
drivers/md/bcache/bcache.h | 4 ++--
drivers/md/bcache/btree.c | 2 +-
drivers/md/bcache/super.c | 2 +-
4 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index 52035a78d836..4493ff57476d 100644
--- 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 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve,
}

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 4fd03d2496d8..5ff6e9573935 100644
--- 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 3d8bd0692af3..e2a719fed53b 100644
--- 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 1bbdc410ee3c..7057ec48f3d1 100644
--- 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;
--
2.26.2