From 3764647b255aafb590d03066d5c1a344463e3637 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@kernel.org>
Date: Wed, 13 Sep 2023 23:08:29 +0200
Subject: [PATCH] bcachefs: Remove undefined behavior in
bch2_dev_buckets_reserved()
In general it's a good idea to avoid using bare unreachable() because it
introduces undefined behavior in compiled code. In this case it even
confuses GCC into emitting an empty unused
bch2_dev_buckets_reserved.part.0() function.
Use BUG() instead, which is nice and defined. While in theory it should
never trigger, if something were to go awry and the BCH_WATERMARK_NR
case were to actually hit, the failure mode is much more robust.
Fixes the following warnings:
vmlinux.o: warning: objtool: bch2_bucket_alloc_trans() falls through to next function bch2_reset_alloc_cursors()
vmlinux.o: warning: objtool: bch2_dev_buckets_reserved.part.0() is missing an ELF size annotation
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
fs/bcachefs/buckets.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/bcachefs/buckets.h b/fs/bcachefs/buckets.h
index f192809f50cf0..0eff05c79c659 100644
--- a/fs/bcachefs/buckets.h
+++ b/fs/bcachefs/buckets.h
@@ -180,7 +180,7 @@ static inline u64 bch2_dev_buckets_reserved(struct bch_dev *ca, enum bch_waterma
switch (watermark) {
case BCH_WATERMARK_NR:
- unreachable();
+ BUG();
case BCH_WATERMARK_stripe:
reserved += ca->mi.nbuckets >> 6;
fallthrough;
--
2.30.2