bcachefs: mempoolify btree_trans

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs.h

@@ -580,6 +580,8 @@ struct bch_fs {
 	struct mutex		btree_interior_update_lock;
 	struct closure_waitlist	btree_interior_update_wait;
 
+	mempool_t		btree_iters_pool;
+
 	struct workqueue_struct	*wq;
 	/* copygc needs its own workqueue for index updates.. */
 	struct workqueue_struct	*copygc_wq;

fs/bcachefs/btree_iter.c

@@ -1648,10 +1648,7 @@ static int btree_trans_realloc_iters(struct btree_trans *trans)
 
 	bch2_trans_unlock(trans);
 
-	new_iters = kmalloc(sizeof(struct btree_iter) * BTREE_ITER_MAX,
-			    GFP_NOFS);
-	if (!new_iters)
-		return -ENOMEM;
+	new_iters = mempool_alloc(&trans->c->btree_iters_pool, GFP_NOFS);
 
 	memcpy(new_iters, trans->iters,
 	       sizeof(struct btree_iter) * trans->nr_iters);
@@ -1679,12 +1676,10 @@ static int btree_trans_realloc_iters(struct btree_trans *trans)
 	return 0;
 }
 
-int bch2_trans_preload_iters(struct btree_trans *trans)
+void bch2_trans_preload_iters(struct btree_trans *trans)
 {
-	if (trans->iters != trans->iters_onstack)
-		return 0;
-
-	return btree_trans_realloc_iters(trans);
+	if (trans->iters == trans->iters_onstack)
+		btree_trans_realloc_iters(trans);
 }
 
 static struct btree_iter *__btree_trans_get_iter(struct btree_trans *trans,
@@ -1868,7 +1863,7 @@ int bch2_trans_exit(struct btree_trans *trans)
 
 	kfree(trans->mem);
 	if (trans->iters != trans->iters_onstack)
-		kfree(trans->iters);
+		mempool_free(trans->iters, &trans->c->btree_iters_pool);
 	trans->mem	= (void *) 0x1;
 	trans->iters	= (void *) 0x1;
 	return ret;

fs/bcachefs/btree_iter.h

@@ -270,7 +270,7 @@ static inline int btree_iter_err(struct bkey_s_c k)
 
 /* new multiple iterator interface: */
 
-int bch2_trans_preload_iters(struct btree_trans *);
+void bch2_trans_preload_iters(struct btree_trans *);
 void bch2_trans_iter_free(struct btree_trans *,
 				struct btree_iter *);
 

fs/bcachefs/fsck.c

@@ -398,7 +398,7 @@ static int check_dirents(struct bch_fs *c)
 
 	bch2_trans_init(&trans, c);
 
-	BUG_ON(bch2_trans_preload_iters(&trans));
+	bch2_trans_preload_iters(&trans);
 
 	iter = bch2_trans_get_iter(&trans, BTREE_ID_DIRENTS,
 				   POS(BCACHEFS_ROOT_INO, 0), 0);
@@ -539,7 +539,7 @@ static int check_xattrs(struct bch_fs *c)
 
 	bch2_trans_init(&trans, c);
 
-	BUG_ON(bch2_trans_preload_iters(&trans));
+	bch2_trans_preload_iters(&trans);
 
 	iter = bch2_trans_get_iter(&trans, BTREE_ID_XATTRS,
 				   POS(BCACHEFS_ROOT_INO, 0), 0);

fs/bcachefs/super.c

@@ -372,6 +372,7 @@ static void bch2_fs_free(struct bch_fs *c)
 	bch2_fs_compress_exit(c);
 	percpu_free_rwsem(&c->usage_lock);
 	free_percpu(c->usage_percpu);
+	mempool_exit(&c->btree_iters_pool);
 	mempool_exit(&c->btree_bounce_pool);
 	bioset_exit(&c->btree_bio);
 	mempool_exit(&c->btree_interior_update_pool);
@@ -600,6 +601,8 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
 	    percpu_init_rwsem(&c->usage_lock) ||
 	    mempool_init_kvpmalloc_pool(&c->btree_bounce_pool, 1,
 					btree_bytes(c)) ||
+	    mempool_init_kmalloc_pool(&c->btree_iters_pool, 1,
+			sizeof(struct btree_iter) * BTREE_ITER_MAX) ||
 	    bch2_io_clock_init(&c->io_clock[READ]) ||
 	    bch2_io_clock_init(&c->io_clock[WRITE]) ||
 	    bch2_fs_journal_init(&c->journal) ||