From: Gustavo A. R. Silva Date: Thu, 13 Nov 2025 05:36:30 +0000 (+0800) Subject: bcache: Avoid -Wflex-array-member-not-at-end warning X-Git-Tag: v6.19-rc1~168^2~49^2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=699122b590ebbc450737eebde3ab8f5b871cc7f0;p=thirdparty%2Fkernel%2Flinux.git bcache: Avoid -Wflex-array-member-not-at-end warning -Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. Use the new TRAILING_OVERLAP() helper to fix the following warning: drivers/md/bcache/bset.h:330:27: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] This helper creates a union between a flexible-array member (FAM) and a set of MEMBERS that would otherwise follow it. This overlays the trailing MEMBER struct btree_iter_set stack_data[MAX_BSETS]; onto the FAM struct btree_iter::data[], while keeping the FAM and the start of MEMBER aligned. The static_assert() ensures this alignment remains, and it's intentionally placed immediately after the corresponding structures --no blank line in between. Signed-off-by: Gustavo A. R. Silva Signed-off-by: Coly Li Signed-off-by: Jens Axboe --- diff --git a/drivers/md/bcache/bset.h b/drivers/md/bcache/bset.h index 011f6062c4c04..6ee2c6a506a26 100644 --- a/drivers/md/bcache/bset.h +++ b/drivers/md/bcache/bset.h @@ -327,9 +327,13 @@ struct btree_iter { /* Fixed-size btree_iter that can be allocated on the stack */ struct btree_iter_stack { - struct btree_iter iter; - struct btree_iter_set stack_data[MAX_BSETS]; + /* Must be last as it ends in a flexible-array member. */ + TRAILING_OVERLAP(struct btree_iter, iter, data, + struct btree_iter_set stack_data[MAX_BSETS]; + ); }; +static_assert(offsetof(struct btree_iter_stack, iter.data) == + offsetof(struct btree_iter_stack, stack_data)); typedef bool (*ptr_filter_fn)(struct btree_keys *b, const struct bkey *k);