From c749c11b04444ca40941dd2ddc5802faed148f6a Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Fri, 16 Feb 2024 13:44:04 -0500 Subject: ioq: Ensure ioq_ent is sufficiently aligned The natural alignment of struct ioq_ent is only 2 on m68k, so over-align it to at least 4 bytes on all platforms. Link: https://buildd.debian.org/status/fetch.php?pkg=bfs&arch=m68k&ver=3.1-1&stamp=1707699583 --- src/ioq.c | 2 +- src/ioq.h | 9 ++++++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/src/ioq.c b/src/ioq.c index cf0b927..f23b62f 100644 --- a/src/ioq.c +++ b/src/ioq.c @@ -177,7 +177,7 @@ typedef atomic uintptr_t ioq_slot; #define IOQ_SKIP_ONE (~IOQ_BLOCKED) // Need room for two flag bits -bfs_static_assert(alignof(struct ioq_ent) > 2); +bfs_static_assert(alignof(struct ioq_ent) >= (1 << 2)); /** * An MPMC queue of I/O commands. diff --git a/src/ioq.h b/src/ioq.h index 30e90e0..818eea6 100644 --- a/src/ioq.h +++ b/src/ioq.h @@ -32,12 +32,19 @@ enum ioq_op { IOQ_STAT, }; +/** + * The I/O queue implementation needs two tag bits in each pointer to a struct + * ioq_ent, so we need to ensure at least 4-byte alignment. The natural + * alignment is enough on most architectures, but not m68k, so over-align it. + */ +#define IOQ_ENT_ALIGN alignas(4) + /** * An I/O queue entry. */ struct ioq_ent { /** The I/O operation. */ - enum ioq_op op; + IOQ_ENT_ALIGN enum ioq_op op; /** The return value (on success) or negative error code (on failure). */ int result; -- cgit v1.2.3