From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Wed, 2 Apr 2025 21:23:22 +0000 (-0400)
Subject: bcachefs: reduce new_stripe_alloc_buckets() stack usage
X-Git-Tag: v6.16-rc1~211^2~198
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2a81bd454c45c89b167b6c2bd3ba7b5a489b0830;p=thirdparty%2Fkernel%2Flinux.git

bcachefs: reduce new_stripe_alloc_buckets() stack usage

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

diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index f68e5f6849b05..31d2207a071b6 100644
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -829,15 +829,15 @@ static int bucket_alloc_set_writepoint(struct bch_fs *c,
 	unsigned i;
 	int ret = 0;
 
-	req->ptrs2.nr = 0;
+	req->scratch_ptrs.nr = 0;
 
 	open_bucket_for_each(c, &req->wp->ptrs, ob, i) {
 		if (!ret && want_bucket(c, req, ob))
 			ret = add_new_bucket(c, req, ob);
 		else
-			ob_push(c, &req->ptrs2, ob);
+			ob_push(c, &req->scratch_ptrs, ob);
 	}
-	req->wp->ptrs = req->ptrs2;
+	req->wp->ptrs = req->scratch_ptrs;
 
 	return ret;
 }
@@ -1214,7 +1214,7 @@ deallocate_extra_replicas(struct bch_fs *c,
 	unsigned extra_replicas = req->nr_effective - req->nr_replicas;
 	unsigned i;
 
-	req->ptrs2.nr = 0;
+	req->scratch_ptrs.nr = 0;
 
 	open_bucket_for_each(c, &req->ptrs, ob, i) {
 		unsigned d = ob_dev(c, ob)->mi.durability;
@@ -1223,11 +1223,11 @@ deallocate_extra_replicas(struct bch_fs *c,
 			extra_replicas -= d;
 			ob_push(c, &req->wp->ptrs, ob);
 		} else {
-			ob_push(c, &req->ptrs2, ob);
+			ob_push(c, &req->scratch_ptrs, ob);
 		}
 	}
 
-	req->ptrs = req->ptrs2;
+	req->ptrs = req->scratch_ptrs;
 }
 
 /*
diff --git a/fs/bcachefs/alloc_foreground.h b/fs/bcachefs/alloc_foreground.h
index ae8ca3b7786bb..192203410d4ec 100644
--- a/fs/bcachefs/alloc_foreground.h
+++ b/fs/bcachefs/alloc_foreground.h
@@ -36,7 +36,6 @@ struct alloc_request {
 
 	/* These fields are used primarily by open_bucket_add_buckets */
 	struct open_buckets	ptrs;
-	struct open_buckets	ptrs2;
 	unsigned		nr_effective;	/* sum of @ptrs durability */
 	bool			have_cache;	/* have we allocated from a 0 durability dev */
 	struct bch_devs_mask	devs_may_alloc;
@@ -62,6 +61,13 @@ struct alloc_request {
 		u64		skipped_nouse;
 		u64		skipped_mi_btree_bitmap;
 	} counters;
+
+	unsigned		scratch_nr_replicas;
+	unsigned		scratch_nr_effective;
+	bool			scratch_have_cache;
+	enum bch_data_type	scratch_data_type;
+	struct open_buckets	scratch_ptrs;
+	struct bch_devs_mask	scratch_devs_may_alloc;
 };
 
 struct dev_alloc_list bch2_dev_alloc_list(struct bch_fs *,
diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 11f46dccc14f4..37e63137041c9 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -1720,12 +1720,12 @@ static int new_stripe_alloc_buckets(struct btree_trans *trans,
 	unsigned i, j, nr_have_parity = 0, nr_have_data = 0;
 	int ret = 0;
 
-	enum bch_data_type	saved_data_type		= req->data_type;
-	struct open_buckets	saved_ptrs		= req->ptrs;
-	unsigned		saved_nr_replicas	= req->nr_replicas;
-	unsigned		saved_nr_effective	= req->nr_effective;
-	bool			saved_have_cache	= req->have_cache;
-	struct bch_devs_mask	saved_devs_may_alloc	= req->devs_may_alloc;
+	req->scratch_data_type		= req->data_type;
+	req->scratch_ptrs		= req->ptrs;
+	req->scratch_nr_replicas	= req->nr_replicas;
+	req->scratch_nr_effective	= req->nr_effective;
+	req->scratch_have_cache		= req->have_cache;
+	req->scratch_devs_may_alloc	= req->devs_may_alloc;
 
 	req->devs_may_alloc	= h->devs;
 	req->have_cache		= true;
@@ -1801,12 +1801,12 @@ static int new_stripe_alloc_buckets(struct btree_trans *trans,
 			goto err;
 	}
 err:
-	req->data_type		= saved_data_type;
-	req->ptrs		= saved_ptrs;
-	req->nr_replicas	= saved_nr_replicas;
-	req->nr_effective	= saved_nr_effective;
-	req->have_cache		= saved_have_cache;
-	req->devs_may_alloc	= saved_devs_may_alloc;
+	req->data_type		= req->scratch_data_type;
+	req->ptrs		= req->scratch_ptrs;
+	req->nr_replicas	= req->scratch_nr_replicas;
+	req->nr_effective	= req->scratch_nr_effective;
+	req->have_cache		= req->scratch_have_cache;
+	req->devs_may_alloc	= req->scratch_devs_may_alloc;
 	return ret;
 }