On 2020/8/25 14:17, Hannes Reinecke wrote:
> On 8/22/20 1:45 PM, Coly Li wrote:
>> Currently although the bcache code has a framework for multiple caches
>> in a cache set, but indeed the multiple caches never completed and users
>> use md raid1 for multiple copies of the cached data.
>>
>> This patch does the following change in struct cache_set, to explicitly
>> make a cache_set only have single cache,
>> - Change pointer array "*cache[MAX_CACHES_PER_SET]" to a single pointer
>> "*cache".
>> - Remove pointer array "*cache_by_alloc[MAX_CACHES_PER_SET]".
>> - Remove "caches_loaded".
>>
>> Now the code looks as exactly what it does in practic: only one cache is
>> used in the cache set.
>>
>> Signed-off-by: Coly Li <colyli@xxxxxxx>
>> ---
>> drivers/md/bcache/alloc.c | 2 +-
>> drivers/md/bcache/bcache.h | 8 +++-----
>> drivers/md/bcache/super.c | 19 ++++++++-----------
>> 3 files changed, 12 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
>> index 4493ff57476d..3385f6add6df 100644
>> --- a/drivers/md/bcache/alloc.c
>> +++ b/drivers/md/bcache/alloc.c
>> @@ -501,7 +501,7 @@ int __bch_bucket_alloc_set(struct cache_set *c,
>> unsigned int reserve,
>> bkey_init(k);
>> - ca = c->cache_by_alloc[0];
>> + ca = c->cache;
>> b = bch_bucket_alloc(ca, reserve, wait);
>> if (b == -1)
>> goto err;
>> diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
>> index 5ff6e9573935..aa112c1adba1 100644
>> --- a/drivers/md/bcache/bcache.h
>> +++ b/drivers/md/bcache/bcache.h
>> @@ -519,9 +519,7 @@ struct cache_set {
>> struct cache_sb sb;
>> - struct cache *cache[MAX_CACHES_PER_SET];
>> - struct cache *cache_by_alloc[MAX_CACHES_PER_SET];
>> - int caches_loaded;
>> + struct cache *cache;
>> struct bcache_device **devices;
>> unsigned int devices_max_used;
>> @@ -808,7 +806,7 @@ static inline struct cache *PTR_CACHE(struct
>> cache_set *c,
>> const struct bkey *k,
>> unsigned int ptr)
>> {
>> - return c->cache[PTR_DEV(k, ptr)];
>> + return c->cache;
>> }
>> static inline size_t PTR_BUCKET_NR(struct cache_set *c,
>> @@ -890,7 +888,7 @@ do { \
>> /* Looping macros */
>> #define for_each_cache(ca, cs, iter) \
>> - for (iter = 0; ca = cs->cache[iter], iter < (cs)->sb.nr_in_set;
>> iter++)
>> + for (iter = 0; ca = cs->cache, iter < 1; iter++)
>> #define for_each_bucket(b, ca) \
>> for (b = (ca)->buckets + (ca)->sb.first_bucket; \
>> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
>> index 7057ec48f3d1..e9ccfa17beb8 100644
>> --- a/drivers/md/bcache/super.c
>> +++ b/drivers/md/bcache/super.c
>> @@ -1675,7 +1675,7 @@ static void cache_set_free(struct closure *cl)
>> for_each_cache(ca, c, i)
>> if (ca) {
>> ca->set = NULL;
>> - c->cache[ca->sb.nr_this_dev] = NULL;
>> + c->cache = NULL;
>> kobject_put(&ca->kobj);
>> }
>>
> Please kill 'for_each_cache()', too, and replace it by an if clause.
Yes, it is done in next patch: [PATCH v2 03/12] bcache: remove
for_each_cache()
Thanks.
Coly Li
