As one can see in include/trace/stages/stage4_event_fields.h, the
implementation of __field() uses the is_signed_type() macro. As one can see
in commit dcf8e5633e2e ("tracing: Define the is_signed_type() macro once"),
there has been an attempt to not make is_signed_type() trigger sparse
warnings for bitwise types. Despite that change, sparse complains when
passing a bitwise type to is_signed_type(). It is not clear to me why.
Follow the example of <trace/events/initcall.h> and suppress the following
sparse warnings by changing __field() into __field_struct():
fs/nilfs2/segment.c: note: in included file (through
include/trace/trace_events.h, include/trace/define_trace.h,
include/trace/events/nilfs2.h):
./include/trace/events/nilfs2.h:191:1: warning: cast to restricted
blk_opf_t
./include/trace/events/nilfs2.h:191:1: warning: restricted blk_opf_t
degrades to integer
./include/trace/events/nilfs2.h:191:1: warning: restricted blk_opf_t
degrades to integer
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Reported-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Closes: https://lore.kernel.org/all/20240430080019.4242-2-konishi.ryusuke@xxxxxxxxx/
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
include/trace/events/nilfs2.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/nilfs2.h b/include/trace/events/nilfs2.h
index 8efc6236f57c..8880c11733dd 100644
--- a/include/trace/events/nilfs2.h
+++ b/include/trace/events/nilfs2.h
@@ -200,7 +200,11 @@ TRACE_EVENT(nilfs2_mdt_submit_block,
__field(struct inode *, inode)
__field(unsigned long, ino)
__field(unsigned long, blkoff)
- __field(enum req_op, mode)
+ /*
+ * Use field_struct() to avoid is_signed_type() on the
+ * bitwise type enum req_op.
+ */
+ __field_struct(enum req_op, mode)
),
TP_fast_assign(
