bcache: remove retry_flush_write from struct cache_set

In struct cache_set, retry_flush_write is added for commit c4dc2497
("bcache: fix high CPU occupancy during journal") which is reverted in
previous patch.

Now it is useless anymore, and this patch removes it from bcache code.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/bcache.h

@@ -706,7 +706,6 @@ struct cache_set {
 
 	atomic_long_t		reclaim;
 	atomic_long_t		flush_write;
-	atomic_long_t		retry_flush_write;
 
 	enum			{
 		ON_ERROR_UNREGISTER,

drivers/md/bcache/journal.c

@@ -447,7 +447,6 @@ static void btree_flush_write(struct cache_set *c)
 		if (!btree_current_write(b)->journal) {
 			mutex_unlock(&b->write_lock);
 			/* We raced */
-			atomic_long_inc(&c->retry_flush_write);
 			goto retry;
 		}
 

drivers/md/bcache/sysfs.c

@@ -83,7 +83,6 @@ read_attribute(state);
 read_attribute(cache_read_races);
 read_attribute(reclaim);
 read_attribute(flush_write);
-read_attribute(retry_flush_write);
 read_attribute(writeback_keys_done);
 read_attribute(writeback_keys_failed);
 read_attribute(io_errors);
@@ -709,9 +708,6 @@ SHOW(__bch_cache_set)
 	sysfs_print(flush_write,
 		    atomic_long_read(&c->flush_write));
 
-	sysfs_print(retry_flush_write,
-		    atomic_long_read(&c->retry_flush_write));
-
 	sysfs_print(writeback_keys_done,
 		    atomic_long_read(&c->writeback_keys_done));
 	sysfs_print(writeback_keys_failed,
@@ -936,7 +932,6 @@ static struct attribute *bch_cache_set_internal_files[] = {
 	&sysfs_cache_read_races,
 	&sysfs_reclaim,
 	&sysfs_flush_write,
-	&sysfs_retry_flush_write,
 	&sysfs_writeback_keys_done,
 	&sysfs_writeback_keys_failed,