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bcachefs: Remove undefined behavior in bch2_dev_buckets_reserved()

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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>
This commit is contained in:
Josh Poimboeuf 2023-09-13 23:08:29 +02:00 committed by Kent Overstreet
parent 0198b2356b
commit 3764647b25
1 changed files with 1 additions and 1 deletions
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2
fs/bcachefs/buckets.h
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@ -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;